Tuesday, January 8, 2019

Bombay trains: Close to eight people die a day on the network; in the first 11 months of 2018, 650 passengers died falling from trains alone, & even more were killed crossing the tracks

‘You Have to Actually Cut Open Mumbai’s Belly’—Inside One of the World’s Most Audacious Transit Projects. Corinne Abrams. The Wall Street Journal, Jan. 6, 2019. https://www.wsj.com/articles/through-monsoons-around-slums-under-templesmumbai-builds-its-first-subway-11546803877

More than 8,000 workers keep construction going 24 hours a day to finish the line that will speed 1.6 million riders beneath one of the world’s most crowded cities

India's financial capital, Mumbai, has taken on its biggest-ever infrastructure project to build a subway in a city where more than seven million commuters cram onto its creaky suburban railways.

Excerpts:

MUMBAI—One of the most challenging projects in the world is being attempted beneath one of its most densely packed cities.

If it works, Mumbai will become the planet’s most crowded metropolis to build an underground subway.

More than 8,000 workers and a fleet of 360-foot-long boring machines are working 24 hours a day—even through monsoon rains—to finish the 27-station, 21-mile subway through some of the world’s most densely populated neighborhoods, around the edge of one of Asia’s biggest slums, below an airport and under temples and colonial buildings to end at a green edge of forest where leopards still roam.

The train is also cutting a path through the country’s religious traditions, legal system and every layer of its society, with challenges at each stop.

The Mumbai Metro Rail Corporation Ltd.—a joint venture between the state and central government, which is building the subway—has had to negotiate with thousands of families and businesses to get them to move and has fought residents in courts over noise, land rights and even whether the subway will sully sacred ground.

Despite the difficulties, the subway, which was started in 2016, is now getting built at a pace of just over one mile a month. So far, 9 miles are complete. The $3.3 billion “Metro Line 3,” Mumbai’s first underground train, is on track to be finished and open by the end of 2021.

With a general election due by May, Prime Minister Narendra Modi is eager to demonstrate he is delivering even the most difficult infrastructure projects for the country’s 1.3 billion citizens.

Mr. Modi said in a speech last month that by 2024 the city would have 170 miles of metro lines under and above ground. The government is “making your lives better and easier” with its metro plans, Mr. Modi said in his speech.

A spokesperson at the prime minister’s office declined to comment on opposition to the metro.

More than seven million commuters a day cram onto the city’s existing creaky suburban railway network. Crowding is so extreme Indian authorities describe it as a “superdense crush load”—meaning trains are often carrying almost three times their capacity. Close to eight people die a day on the network, according to rail officials. In the first 11 months of 2018, 650 passengers died falling from trains alone, and even more were killed crossing the tracks, rail officials said.

The new train will be the first line to cut through the heart of the city, with air-conditioned carriages speeding around 80 feet underground, while carrying an estimated 1.6 million riders a day.

The unlikely driver of this stunning megaproject is a 48-year-old woman who grew up in a small town 200 miles outside Mumbai. Ashwini Bhide aced the notoriously difficult civil-service exam in 1995 and rose through the ranks of Indian civil service to become one of the few women at the top.

“You have to actually cut open Mumbai’s belly at so many locations and then start constructing,” said Ms. Bhide, managing director of the Mumbai Metro Rail Corporation, the MMRC.

Wearing a deep blue kurti, a traditional Indian shirt—one local media group named her the city’s “Most Stylish Bureaucrat”—Ms. Bhide took calls from her desk phone and sent messages from her cellphone recently as she coordinated her mostly male team, who call her “Madam.”
Total deaths 2,734
Crossing tracks 1,476
Falling from trains 650
Natural death 491
Suicide 31
Electric shock 20
Struck by pole when leaning from a train 18
Others 48

Data is for January to November 2018. Source: Mumbai Railway Police


“There is a desperation,” said Ms. Bhide. “We really need to do it. It should have been done yesterday.”

Her office shelves are stacked with awards, a rock from the metro digging and a miniature model of a boring machine. Her walls are a patchwork of maps, plans and diagrams.

The city formerly known as Bombay has always been one of India’s most cosmopolitan and diverse. With a greater metro area population of 18.4 million, almost every religious, ethnic and caste community is represented somewhere along the peninsula. The city’s stock exchange BSE Ltd. shuts down to observe 12 religious holidays, including those observed by Hindus, Muslims and Christians.

India’s tiny Parsi community of 57,000 people—descendants of the Zoroastrian religious minority that came to India from Iran starting centuries ago—are a powerful group with property and temples across the city. At the center of each temple of the 3,500-year-old religion is a holy fire that has often been kept burning more than a century.

The new subway line is set to pass below two of the temples’ grounds. Only Parsis are allowed to enter the temples. Some worry the subway could interrupt prayers and desecrate holy ground, fearing that if nonmembers or menstruating women pass below while riding on it, the sanctity of the temple will be destroyed. Others are concerned tunneling and station work could damage the temples or drain wells on the temple sites.

“It is too close for comfort,” said Jamshed Sukhadwalla, a Parsi who has taken the subway builders to court. “There should not be interference above or below.”

More than 50 Parsis, including priests wearing traditional white robes and hats and women wearing headscarves, turned up at the Bombay High Court during a hearing in July. The lawyer for the MMRC warned the tunnel could collapse if boring stopped for too long.

After a six-month pause in tunneling near the temples, the court in November granted the MMRC permission to restart.

Mr. Sukhadwalla and fellow petitioners appealed in the Supreme Court in New Delhi. Last month, it ruled that work could go ahead as long as measures were taken to avoid damage to the temples.

“To rethink the alignment is virtually impossible,” said Uday Umesh Lalit, one of the judges.

Mr. Sukhadwalla, the Parsi opponent, said after the hearing, “You can give assurances, but if damage occurs” to the temples “it will be irreversible…I’m totally upset.”

The MMRC has faced around 65 court cases related to the construction of the metro, about half of them still open. Among the cases are petitions about land and property rights, noise, religious freedom and from people trying to protect trees along the length of the metro line.

To finish the line as fast as possible, 17 tunnel-boring machines—each almost as long as a football field—are simultaneously grinding through rock below the city.

To get the machines from the port and through Mumbai’s narrow roads, specialists had to divide the machines into parts and transport them on trailers. They cut off shop fronts to fit the machines down streets. The machines were reassembled underground.

Only the Bangladeshi capital of Dhaka is more crowded than Mumbai, according to the United Nations. Dhaka is building an aboveground metro. Mumbai has an average of around 82,000 people per square mile, three times the population density of New York City.

Ms. Bhide isn’t moving the line away from packed neighborhoods; she’s steering straight at them.

“These areas, if they really need to be rejuvenated, they have to have metro connectivity,” she said. The city’s old lines will continue to exist above ground. In addition to the new underground subway, routes are also being constructed above ground.

South Mumbai’s streets are lined with poorly maintained buildings put up during colonial times. The MMRC surveyed thousands of structures before construction took place, reinforcing ones in danger of falling over.

[...]

Lawyer Robin Jaisinghani’s apartment peers into the station’s crater and he says the 24-hour construction was keeping his young daughters up at night. More than once he visited the construction site in the early hours of the morning to ask them to stop.

The MMRC put up a sound barrier, but sitting in his apartment, Mr. Jaisinghani said he could still hear the noise through the double-glazed German windows he had installed to block it out.

He represented himself in court, saying the noise violated his constitutional right to life and personal liberty, and got an order to stop construction between 10 p.m. and 6 a.m. For more than a year, the station near his home was the only train construction site in Mumbai that halted at night.

Courts ruled in August that the building of this crucial infrastructure was more important than the inconvenience of residents. Construction is back to 24 hours a day.

At the other end of the line and the economic spectrum lies the final stop of the metro, Aarey Milk Colony, a rare expanse of green once known for its dairy business.

The stop, and a depot for trains, is being built over an area where families lived in simple brick homes, raising chickens and farming in the surrounding government lands.

Around 42% of Mumbai residents live in slums, according to 2011 census data, the most recent available, on land they don’t own and sometimes in teetering little towers. Relocating residents is a complex process.

Laxmi Ramji Gaikwad, in her 70s, lived on what was officially government land. The settlement was on land that flowed into a sprawling nature reserve, home to more than 20 leopards that occasionally attack locals. In 2017, a leopard attacked and killed a child.

When officials came to evict her to make way for the train, Ms. Gaikwad said she threatened to set herself on fire. She said security guards removed her possessions and destroyed her home. She finally agreed to relocate to a small apartment on the 12th floor of a government building.

Her legs have swelled from inactivity since moving, she says, and she feels dizzy when she looks out the window. She has always used wood fires and isn’t sure how to use a gas stove to make tea.

“I don’t know what benefit the metro will bring,” she said.

The MMRC has moved more than 2,800 families and businesses along the subway route. It says all moves are “legally done under supervision of relevant government authorities after alternative accommodation is provided.” It says it helps families adjust, teaching them how to pay bills and look after their new homes.

Ms. Bhide said she devours old books about how infrastructure was built during the colonial era. People died to build the railway lines Mumbaikars depend on today, she tells her team. No one has died building her subway line.

“People have taken a lot of pains, and a lot of lives were lost building the infrastructure we see today and we have been using for the past 150 years,” she said. “We have to have that patience.”

—-Debiprasad Nayak, Karan Deep Singh and Eric Bellman contributed to this article.

[links, graphs, charts, interesting data, full text, at the link above]

Having moral employees & leaders can come with many benefits; there can be offsetting costs associated with an internalized moral identity (reduced humor & subsequent likability in the workplace)

Yam, K. C., Barnes, C. M., Leavitt, K., Wei, W., Lau, J., & Uhlmann, E. L. (2019). Why so serious? A laboratory and field investigation of the link between morality and humor. Journal of Personality and Social Psychology, http://dx.doi.org/10.1037/pspi0000171

Abstract: Previous research has identified many positive outcomes resulting from a deeply held moral identity, while overlooking potential negative social consequences for the moral individual. Drawing from Benign Violation Theory, we explore the tension between moral identity and humor, and the downstream workplace consequence of such tension. Consistent with our hypotheses, compared with participants in the control condition, participants whose moral identities were situationally activated (Study 1a) or chronically accessible (Study 1b) were less likely to appreciate humor and generate jokes others found funny (Study 2), especially humor that involved benign moral violations. We also found that participants with a strong moral identity do not generally compensate for their lack of humor by telling more jokes that do not involve moral violations (Study 3). Additional field studies demonstrated that employees (Study 4) and leaders (Study 5) with strong moral identities and who display ethical leadership are perceived as less humorous by their coworkers and subordinates, and to the extent that this is the case are less liked in the workplace. Study 5 further demonstrated two competing mediating pathways—leaders with strong moral identities are perceived as less humorous but also as more trustworthy, with differentiated effects on interpersonal liking. Although having moral employees and leaders can come with many benefits, our research shows that there can be offsetting costs associated with an internalized moral identity: reduced humor and subsequent likability in the workplace.

Microscopic description of chaotic systems' synchronization: Gradual process of topological adjustment in phase space, in which the strange attractors of the two coupled systems continuously converge

Synchronization of chaotic systems: A microscopic description. Nir Lahav, Irene Sendina-Nadal, Chittaranjan Hens, Baruch Ksherim, Baruch Barzel, Reuven Cohen, and Stefano Boccaletti. Phys. Rev. E 98, 052204, https://journals.aps.org/pre/abstract/10.1103/PhysRevE.98.052204

Abstract: The synchronization of coupled chaotic systems represents a fundamental example of self organization and collective behavior. This well-studied phenomenon is classically characterized in terms of macroscopic parameters, such as Lyapunov exponents, that help predict the system's transitions into globally organized states. However, the local, microscopic, description of this emergent process continues to elude us. Here we show that at the microscopic level, synchronization is captured through a gradual process of topological adjustment in phase space, in which the strange attractors of the two coupled systems continuously converge, taking similar form, until complete topological synchronization ensues. We observe the local nucleation of topological synchronization in specific regions of the system's attractor, providing early signals of synchrony, that appear significantly before the onset of complete synchronization. This local synchronization initiates at the regions of the attractor characterized by lower expansion rates, in which the chaotic trajectories are least sensitive to slight changes in initial conditions. Our findings offer an alternative description of synchronization in chaotic systems, exposing its local embryonic stages that are overlooked by the currently established global analysis. Such local topological synchronization enables the identification of configurations where prediction of the state of one system is possible from measurements on that of the other, even in the absence of global synchronization.

Why would Parkinson’s disease lead to sudden changes in creativity, motivation, or style with visual art?: A review of case evidence and new, contextual, and genetic hypotheses

Why would Parkinson’s disease lead to sudden changes in creativity, motivation, or style with visual art?: A review of case evidence and new, contextual, and genetic hypotheses. Jon O. Lauring et al. Neuroscience & Biobehavioral Reviews, https://doi.org/10.1016/j.neubiorev.2018.12.016

Highlights
•    Case evidence suggests PD may lead to interest, creativity, change in produced art.
•    Occurs in both established artists and those without prior desire toward art making.
•    We review case evidence and relate to current knowledge on PD symptoms/neurobiology.
•    Propose hypothesis of selective damage + agonist overstimulation of mesolimbic areas.
•    Also relate to context, personality, genetic differences offering window into artistic brain.

Abstract: Parkinson’s disease (PD) is a devastating diagnosis with, however, potential for an extremely intriguing aesthetic component. Despite motor and cognitive deficits, an emerging collection of studies report a burst of visual artistic output and alterations in produced art in a subgroup of patients. This provides a unique window into the neurophysiological bases for why and how we might create and enjoy visual art, as well as into general brain function and the nature of PD or other neurodegenerative diseases. However, there has not been a comprehensive organization of literature on this topic. Nor has there been an attempt to connect case evidence and knowledge on PD with present understanding of visual art making in psychology and neuroaesthetics in order to propose hypotheses for documented artistic changes. Here, we collect the current research on this topic, tie this to PD symptoms and neurobiology, and provide new theories focusing on dopaminergic neuron damage, over-stimulation from dopamine agonist therapy, and context or genetic factors revealing the neurobiological basis of the visual artistic brain.

Better to overestimate than to underestimate others’ feelings: Asymmetric cost of errors in affective perspective-taking

Better to overestimate than to underestimate others’ feelings: Asymmetric cost of errors in affective perspective-taking. Nadav Klein. Organizational Behavior and Human Decision Processes, Volume 151, March 2019, Pages 1-15. https://doi.org/10.1016/j.obhdp.2018.12.009

Highlights
•    Errors in perspective taking are common but little is known about their consequences.
•    Is it worse to overestimate or underestimate the intensity others' emotions?
•    Seven experiments find that underestimating emotions is costlier than overestimating.
•    This occurs because underestimation is thought to indicatelower effort and empathy.
•    Stereotypical emotions and socially undesirable emotions moderate these results.

Abstract: Accurately assessing other people’s perspective in general, and other people’s emotional responses in particular, is essential for successful social interaction. However, substantial research finds that accurate perspective taking is the exception rather than the norm. Although errors in perspective taking are common, little is known about their consequences. Is it worse to overestimate or to underestimate other people’s emotional responses? Seven experiments find that underestimating the intensity of other people's emotional responses leads to more negative evaluations than overestimating others’ emotions (Experiments 1–5). These results replicate across emotional valence and across observers and targets and occur because people believe that underestimation is indicative of lower effort and empathy in trying to understand the target. Additional experiments identify moderators of these effects, including stereotypical emotions and socially undesirable emotions (Experiments 6–7). The cost of errors in affective perspective taking is asymmetric, leading to important implications for social coordination.


Found that vegetarian dietary patterns were associated with a higher incidence of morbid obesity culminating in bariatric surgery; refined and processed vegetarian food consumption should be discouraged

Which Is a Good Diet—Veg or Non-veg? Faith-Based Vegetarianism for Protection From Obesity—a Myth or Actuality? Sanjay Borude. Obesity Surgery, https://link.springer.com/article/10.1007/s11695-018-03658-7

Abstract
Introduction: India ranks first among nations with the largest population of vegetarians, and 40% of Asian Indians are vegetarian. There seems to occur a “nutrition transition” among vegetarians in India with a decline in the consumption of whole plant food content and replacement with processed foods, fried foods, and refined carbohydrates. This study evaluates the association between the consumption of a vegetarian diet and the prevalence of morbid obesity necessitating bariatric surgery in Asian Indians.

Material and Methods: This is a retrospective cohort study analyzing records of 235 Indian patients suffering from morbid obesity and who underwent bariatric surgery at our center through the years 2015 to 2017. Pearson’s chi-square test for independence of attributes was applied to analyze the difference between a number of vegetarians versus non-vegetarians undergoing bariatric surgery.

Results: The difference in the number of vegetarians versus non-vegetarians undergoing bariatric surgery was not significant for years 2015 and 2017, but the number was numerically higher for vegetarians. The difference was significantly higher for vegetarians in the year 2016. The difference in female vegetarians versus female non-vegetarians undergoing bariatric surgery was not significant for the year 2017 but was significantly higher for vegetarians during the years 2015 and 2016. The difference in male vegetarians versus non-vegetarians undergoing bariatric surgery was not significant for all the years.

Conclusion: In an Asian Indian cohort, we found that vegetarian dietary patterns were associated with a higher incidence of morbid obesity culminating in bariatric surgery. Our study is a myth breaker that all vegetarian diets are healthy diets. Our findings can be utilized to discourage refined and processed food consumption and promote healthy vegetarian food choices.

Keywords: Vegetarian Non-vegetarian Diet Bariatric surgery Morbid obesity Meat Vegan Asian Indian

The Mona Lisa Illusion—Scientists See Her Looking at Them Though She Isn’t

The Mona Lisa Illusion—Scientists See Her Looking at Them Though She Isn’t. Gernot Horstmann, Sebastian Loth. i-Perception, https://doi.org/10.1177/2041669518821702

Abstract: If the person depicted in an image gazes at the camera or painter, a viewer perceives this as being gazed at. The viewers’ perception holds irrespectively of their position relative to image. This is the Mona Lisa effect named after the subject of Leonardo’s famous painting La Gioconda. The effect occurs reliably but was not tested with Mona Lisa herself. Remarkably, viewers judged Mona Lisa’s gaze as directed to their right-hand side irrespectively of the image zoom, its horizontal position on screen, and the distance of the ruler that was used for measuring the gaze direction.

Keywords: gaze direction, Mona Lisa effect, picture perception



Monday, January 7, 2019

Author estimates the degree to which scientists are willing to change the direction of their work in exchange for resources

Myers, Kyle, The Elasticity of Science (August 22, 2018). http://dx.doi.org/10.2139/ssrn.3176991

Abstract: This paper estimates the degree to which scientists are willing to change the direction of their work in exchange for resources. Novel data from the National Institutes of Health is used to estimate an entry model that accounts for strategic interactions. Inducing a scientist to change their direction by 1 standard deviation, a qualitatively small difference, requires a four-fold increase in funds, an extra $1 million per year. But at current levels, the costs and benefits of directed versus undirected research appear to be quite similar.

Keywords: economics of science
JEL Classification: H50, I23, O31, O33, O38

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How Do We Redirect Scientific Investigation? Chuck Dinerstein. ACSH, Jan 2 2019. https://www.acsh.org/news/2019/01/02/how-do-we-redirect-scientific-investigation-13698

The economic term for haggling over the size of the carrot is elasticity. Using NIH grant data from 2002 to 2009 and the similarity of applicants’ prior work to the objectives of each RFA grant a recent paper looks at the scientists’ bargain. The measure of similarity was based upon how much of scientists prior published abstracts used terminology found in the individual RFA application research objectives – the underlying assumption was the use of the same scientific language was a useful marker for the underlying science to be similar.

It is no surprise that scientists apply to highly “similar” projects, especially when they are more readily available, because of less competition, and come with good funding. So what tradeoffs do scientists make changing course and applying for less similar projects?

*    The more aligned a scientist’s and RFA research interest, the less weight is put on the amount of the total award. But as the similarity becomes less, the amount of the grant rises. A "30% less" similar field would be where a researcher was studying a vaccine for a particular virus using a specific research animal and was asked instead to investigate a vaccine for a different virus but still using the same research animal and approach. By the author’s calculation scientists require an additional $1 million/annually to change course.
*    Competition for grants is another consideration, and the author found that scientists traded an increased award size of about $80,000 for one more competitor for funding.

Put into other words, scientists are willing to be redirected, but it comes at a cost, an award about 65% greater than what they might have gotten for staying the course. That premium helps cover the adjustments necessary for tangibles, like equipment and the intangible, research preferences.

*    RFA grants result in a 16 - 24% increase in publications. But that direction is short-lived with many researchers returning to their “primary interests” once the research award ends.
*    When looking at the output of both the winners and “losers” of the RFA awards, there seems to be no difference in quantity or quality, as measured by the publishing journal’s “impact.” In the words of the author, RFA’s “create more not better science.”

What can we conclude? Not surprisingly, applicants choose the path they believe will be most likely to be funded. To get more externally directed research, to move science in the direction of “our choosing,” we must pay for a larger carrot and “…it is likely  that much larger,  sustained  levels of investments  would  be necessary  to  generate meaningful  long-run  changes.” As with all things, when we look at the devil in the details, we find human behavior is often more than “if you build it, they will come.”

The self–other knowledge asymmetry in cognitive intelligence, emotional intelligence, and creativity

The self–other knowledge asymmetry in cognitive intelligence, emotional intelligence, and creativity. Aljoscha C. Neubauer et al. Heliyon, Volume 4, Issue 12, December 2018, e01061. https://doi.org/10.1016/j.heliyon.2018.e01061

Abstract: The self–other knowledge asymmetry model (SOKA) assumes that some personality traits might be open to oneself and other persons (‘open area’), while other traits are more accurately perceived by others (‘blind spot’); a third group of traits might be visible only to oneself and not to others (‘hidden area’), and finally a trait might neither be visible to oneself nor to one's peers (‘unknown area’). So far, this model has been tested only for personality traits and general intelligence, not for more specific abilities; to do so was the novel intention of our study. We tested which of six abilities (verbal, numerical, and spatial intelligence; interpersonal and intrapersonal competence; and creative potential/divergent thinking ability) are in which SOKA area. We administered performance tests for the six abilities in two samples – 233 14-year-olds and 215 18-year-olds – and collected self- and peer-ratings for each domain. Numerical intelligence and creativity were judged validly both from self- and peer-perspectives (‘open area’). In the younger sample verbal intelligence was validly estimated only by peers (‘blind spot’), whereas the older group showed some insight into their own abilities as well (‘blind spot’ to ‘open area’). While in the younger group only the pupils themselves could validly estimate their intra- and interpersonal competence (‘hidden area’), in the older group peers were also successful in estimating other's interpersonal competence, albeit only with low accuracy (‘hidden area’ to ‘open area’). For 18-year-olds, spatial ability was in the hidden area too, but in 14-year-olds this could neither be validly estimated by pupils themselves nor by peers (‘unknown area’). These results implicate the possibility of non-optimal career choices of young people, and could, therefore, be helpful in guiding professional career counselling.

Few psychological or physiological processes are universally beneficial; most positive phenomena reach inflection points where their effects turn negative; mindfulness is unlikely to be an exception

Can Mindfulness Be Too Much of a Good Thing? The Value of a Middle Way. Willoughby B Britton. Current Opinion in Psychology, https://doi.org/10.1016/j.copsyc.2018.12.011

Highlights
•    Few psychological or physiological processes are universally beneficial.
•    Most positive phenomena reach inflection points where their effects turn negative.
•    Mindfulness is unlikely to be an exception to the inverted U-shape curved principle.
•    Some mindfulness-related processes have negative effects under certain conditions.
•    Research that includes the full range of possible effects would improve the efficacy of mindfulness.

Abstract: Previous research has found that very few, if any, psychological or physiological processes are universally beneficial. Instead, positive phenomena tend to follow a non-monotonic or inverted U-shaped trajectory where their typically positive effects eventually turn negative. This review investigates mindfulness-related processes for signs of non-monotonicity. A number of mindfulness-related processes—including, mindful attention (observing awareness, interoception), mindfulness qualities, mindful emotion regulation (prefrontal control, decentering, exposure, acceptance), and meditation practice—show signs of non-monotonicity, boundary conditions, or negative effects under certain conditions. A research agenda that investigates the possibility of mindfulness as non-monotonic may be able to provide an explanatory framework for the mix of positive, null and negative effects that could maximize the efficacy of mindfulness-based interventions.

Between 1950 & 1959, the highest earning 1 percent of Americans paid an effective tax rate of 42 percent. By 2014, it was only down to 36.4 percent

Did the Rich Really Pay Much Higher Taxes in the 1950s? The Answer Is a Little Complicated. Jordan Weissmann. Slate,  Aug 07, 2017. https://slate.com/business/2017/08/the-history-of-tax-rates-for-the-rich.html

American progressives like to remember the mid–20th century as a time when the only thing higher than a Cadillac’s tail fin was the top marginal tax rate (which, during the Eisenhower years peaked above 90 percent for the very rich). Uncle Sam took 90 cents on the dollar off the highest incomes, and—as any good Bernie Sanders devotee will remind you—the economy thrived.

Conservatives, however, often try to push back on this version of history, pointing out that those staggeringly high tax rates existed mostly on paper; relatively few Americans actually paid them. Recently, the Tax Foundation’s Scott Greenberg went so far as to argue that “taxes on the rich were not that much higher” in the 1950s than today. Between 1950 and 1959, he notes, the highest earning 1 percent of Americans paid an effective tax rate of 42 percent. By 2014, it was only down to 36.4 percent—a substantial but by no means astronomical decline.

[https://compote.slate.com/images/c26acb08-3169-4978-80ce-0186380d5b00.png]

Greenberg is not pulling his numbers out of thin air. Rather, he’s drawing them directly from a recent paper by Thomas Piketty, Emmanuel Saez, and Gabriel Zucman in which the three economists—all well-loved by progressives—estimate the average tax rates Americans at different income levels have actually paid over time. Their historical measure includes federal, state, and local levies—including corporate, property, income, estate, sales, and payroll taxes. And lest you think Greenberg is misrepresenting anything, here’s Piketty & co.’s own graph (rates on rich folks are shown in green).

[https://compote.slate.com/images/fe0a06f5-a089-4f6a-97c7-65238fc05a97.png Source: Piketty, Saez, and Zucman]

There are a few obvious reasons why the taxes the rich actually paid in the 1950s were so much lower than the confiscatory top rates that sat on the books. For one, the max tax rates on investment income were far lower than on wages and salaries, which gave a lot of wealthy individuals some relief. Tax avoidance may have also been a big problem. Moreover, there simply weren’t that many extraordinarily rich households. Those fabled 90 percent tax rates only bit at incomes over $200,000, the equivalent of more than $2 million in today’s dollars. As Greenberg notes, the tax may have only applied to 10,000 families.

To Greenberg, the takeaway from this is simple: Progressives should stop fixating on the tax rates from 60 years ago. “All in all, the idea that high-income Americans in the 1950s paid much more of their income in taxes should be abandoned. The top 1 percent of Americans today do not face an unusually low tax burden, by historical standards.”

I’m not convinced. Effective tax rates on 1 percenters may not have fallen by half, as some on the left might be tempted to imagine. But they are down by about 6 percentage points1 at a time when the wealthy earn a vastly larger share of the national income. That drop represents a lot of money. Moreover, as Greenberg admits, tax rates on top 0.1 percent have fallen by about one-fifth since their 1950s heights. That rather severely undercuts the idea that taxes on the wealthy haven’t fallen “much.”

 Moreover, there may be reasons to support higher taxes beyond their ability to raise revenue. One popular theory among left-leaning intellectuals right now—advanced by Piketty, Saez, and their protegée Stefanie Stantcheva—is that high tax rates actually ease income inequality by discouraging CEOs and professionals from demanding exorbitantly high pay for their services.* In other words, thanks to high tax rates, people didn’t bother trying to get as rich. After all, there’s no point in bargaining for a giant bonus if the government is going to clip off most of it. I wouldn’t say the theory has been accepted as a consensus fact at this point, but it’s certainly alive and being taken seriously.

So the real tax rates rich Americans paid in the 1950s may not have been so stratospherically high as some progressives assume. But they also may have helped create a more egalitarian society. That seems worth considering.

[Full text and links in the article above]

There may be a variety of reasons why more democratic states are engaged in higher levels of international trade; a larger concern for consumer interests, however, is likely not among them

The Absence of Consumer Interests in Trade Policy. Timm Betz and Amy Pond. The Journal of Politics, https://www.journals.uchicago.edu/doi/abs/10.1086/701493

Abstract: Why are some countries more open to trade than others? Prominent explanations emphasize differences in the influence of voters as consumers. Consumers benefit from lower prices. Because governments in democracies are more responsive to voters, they should implement lower tariffs. We develop and evaluate an implication of this line of argument. If lower tariffs are a response to consumer interests, lower tariffs should be concentrated on products most relevant to consumers. Using data on consumption shares across product categories, we report evidence that consumer interests do not account for lower tariffs. Governments place higher tariffs on goods with higher consumption shares, and we find no evidence that this relationship attenuates under more democratic institutions. There may be a variety of reasons why more democratic states are engaged in higher levels of international trade. A larger concern for consumer interests, however, is likely not among them.

Keywords: trade, consumers, democracy, tariffs, contract enforcement

Human foetuses and newborns smile first during sleep, before they smile while awake and interacting with caregivers; adults may have true smiling and laughing, a true inner mirth, during sleep

Smiling asleep: A study of happy emotional expressions during adult sleep. Marion Clé et al. Journal of Sleep Research, https://doi.org/10.1111/jsr.12814

Abstract: Human foetuses and newborns smile first during sleep, before they smile while awake and interacting with caregivers. Whether smiling persists during adult sleep, and expresses inner joy, is yet unknown. Smiles were looked for during night‐time video‐polysomnography combined with electromyography of the zygomatic and orbicularis oculi muscles in 100 controls, 22 patients with sleepwalking and 52 patients with rapid eye movement (REM) sleep behaviour disorder. Autonomous reactions (heart rate and level of vasoconstriction) and the presence of rapid eye movements were examined during smiles and laughs. On visual examination of the face video clips synchronous with zygomatic contraction, 8% of controls smiled while asleep (7% in REM sleep and 1% in non‐REM sleep). Some patients with sleepwalking also smiled and laughed during N2 sleep and N3 parasomnia. Half of the patients with REM sleep behaviour disorder smiled and one‐third laughed, mostly during REM sleep. The 173 happy faces included mild smiles (24.8%), open‐mouth smiles (29.5%) and laughs (45.7%). More than half of the smiles were the Duchenne (genuine) type, including an active closure of the eyelids. Approximately half of the smiles and laughs were temporally associated with rapid eye movements. There was no increased heart rate variability during smiles and laughs. Two scenic behaviours including smiles and laughs suggested that the happy facial expression was associated with a happy dreaming scenario. Smiling and laughing occasionally persist during adult sleep. There are several lines of evidence suggesting that these happy emotional expressions reflect a true inner mirth.

Greed: A majority of participants reported an excessive desire for money or materials (clothes, books, &c, 68%); also non-material items (time, love, &c, 32pct)

Understanding greed as a unified construct. Glenn W. Lambie, Jaimie Stickl Haugen. Personality and Individual Differences, Volume 141, 15 April 2019, Pages 31-39, https://doi.org/10.1016/j.paid.2018.12.011

Abstract: The concept of greed is a popular topic since the economic crisis of 2008. Much of the psychological research relating to greed aligns greed as a situation-specific trait as opposed to a dispositional trait. Thus, there is a need to enhance our understanding of greed as a disposition and explore individual differences that may influence behavior. Since individuals conceptualize greed in various ways, there is a lack in understanding of the construct. We propose a unified definition of greed and outline the extant research on dispositional greed, focusing on existing greed assessments. Considering our working definition of greed, we advocate that there is a need for future research to enhance definitional clarity, including the development of an additional greed assessment that more accurately encapsulates this complex construct.

Increased fruit & vegetable consumption can enhance mental well-being; both increasing frequency & increasing quantity matter; a hump-shaped relationship appeared between age & fruit & vegetable consumption

Lettuce be happy: A longitudinal UK study on the relationship between fruit and vegetable consumption and well-being. Neel Ocean, Peter Howley, Jonathan Ensor. Social Science & Medicine, https://doi.org/10.1016/j.socscimed.2018.12.017

Highlights
•    Increased fruit & vegetable consumption can enhance mental well-being.
•    Increasing frequency and increasing quantity of consumption both matter.
•    The relationship is robust to different measures of well-being.
•    A hump-shaped relationship appeared between age and fruit and vegetable consumption.

Abstract
Rationale: While the role of diet in influencing physical health is now well-established, some recent research suggests that increased consumption of fruits and vegetables could play a role in enhancing mental well-being. A limitation with much of this existing research is its reliance on cross-sectional correlations, convenience samples, and/or lack of adequate controls.

Objective: We aim to add to the emerging literature on the relationship between fruit and vegetable consumption and well-being by using longitudinal data from a study in the United Kingdom (UK).

Method: We employ panel data analytical techniques on three waves collected between 2010 and 2017 (i.e., following the same individuals over time) in the UK Household Longitudinal Survey. We also control for time-variant confounders such as diet, health, and lifestyle behaviours.

Results: Fixed effects regressions show that mental well-being (GHQ-12) responds in a dose-response fashion to increases in both the quantity and the frequency of fruit and vegetables consumed. This relationship is robust to the use of subjective well-being (life satisfaction) instead of mental well-being. We also document a hump-shaped relationship between fruit and vegetable consumption and age.

Conclusion: Our findings provide further evidence that persuading people to consume more fruits and vegetables may not only benefit their physical health in the long-run, but also their mental well-being in the short-run.

Sunday, January 6, 2019

The increase in homebuilding construction concentration in the past decade has led to lower production volume, fewer units in the production pipeline, & greater unit price volatility

Cosman, Jacob and Quintero, Luis, Market Concentration in Homebuilding (November 28, 2018). Johns Hopkins Carey Business School Research Paper No. 18-18. https://ssrn.com/abstract=3303984

Abstract: We investigate the impact of increasing concentration in local residential construction markets on housing production. We show that the increase in concentration in the past decade has led to lower production volume, fewer units in the production pipeline, and greater unit price volatility. Our results imply that the greater concentration has decreased the annual value of new housing production by $106 billion. Because housing is a determinant of the business cycle these findings provide further evidence that the secular decline in competitive intensity in the American economy is altering macroeconomic dynamics.

25% of the prosopagnosia sample scored in the tone deaf range; these subjects were impaired in pitch processing, but not rhythm; face recognition ability significantly predicted pitch processing ability

Perception Of Musical Pitch In Developmental Prosopagnosia. Sherryse L.Corrow et al. Neuropsychologia, https://doi.org/10.1016/j.neuropsychologia.2018.12.022

Highlights
•    Some prosopagnosic subjects showed deficits in pitch processing relative to controls
•    Individually, 25% of the prosopagnosia sample scored in the tone deaf range
•    These subjects were impaired in pitch processing, but not rhythm
•    Face recognition ability significantly predicted pitch processing ability

Abstract

Studies of developmental prosopagnosia have often shown that developmental prosopagnosia differentially affects human face processing over non-face object processing. However, little consideration has been given to whether this condition is associated with perceptual or sensorimotor impairments in other modalities. Comorbidities have played a role in theories of other developmental disorders such as dyslexia, but studies of developmental prosopagnosia have often focused on the nature of the visual recognition impairment despite evidence for widespread neural anomalies that might affect other sensorimotor systems.

We studied 12 subjects with developmental prosopagnosia with a battery of auditory tests evaluating pitch and rhythm processing as well as voice perception and recognition. Overall, three subjects were impaired in fine pitch discrimination, a prevalence of 25% that is higher than the estimated 4% prevalence of congenital amusia in the general population. This was a selective deficit, as rhythm perception was unaffected in all 12 subjects. Furthermore, two of the three prosopagnosic subjects who were impaired in pitch discrimination had intact voice perception and recognition, while two of the remaining nine subjects had impaired voice recognition but intact pitch perception.

These results indicate that, in some subjects with developmental prosopagnosia, the face recognition deficit is not an isolated impairment but is associated with deficits in other domains, such as auditory perception. These deficits may form part of a broader syndrome which could be due to distributed microstructural anomalies in various brain networks, possibly with a common theme of right hemispheric predominance.

What Laypeople Think the Big Five Trait Labels Mean: Lay beliefs corresponded generally well with standard Big Five inventories’ content, but there were notable disjunctions between beliefs and the standards

What Laypeople Think the Big Five Trait Labels Mean. Judith A.Hall et al. Journal of Research in Personality, https://doi.org/10.1016/j.jrp.2018.12.007

Highlights
•    Laypeople were able to describe how they apply the Big Five traits in daily life.
•    Each trait had 9 to 13 facets that varied in their centrality to the trait.
•    Lay beliefs corresponded generally well with standard Big Five inventories’ content.
•    But there were notable disjunctions between lay beliefs and inventories’ content.

Abstract: We asked what laypeople think the commonly used Big Five trait labels mean, and how well their beliefs match the content of standard Big Five scales. Study 1 established participants’ familiarity with the Big Five trait labels. In Studies 2 and 3, participants described persons high on the traits using a free response format. Responses were sorted into categories (facets), each of which earned a centrality index defined as the proportion of responses for the given trait that fell into that category. Studies 2 and 3 converged well. Comparisons with four standard Big Five inventories revealed substantial commonality but also notable areas of non-overlap consisting of content identified by laypeople that was not represented in the standard scales, as well as content in the standard scales that was not mentioned by laypeople.

Saturday, January 5, 2019

Beauty ranking of mammalian species kept in the Prague Zoo: does beauty of animals increase the respondents’ willingness to protect them?

Beauty ranking of mammalian species kept in the Prague Zoo: does beauty of animals increase the respondents’ willingness to protect them? Eva Landová et al. The Science of Nature, https://link.springer.com/article/10.1007/s00114-018-1596-3

Abstract: Aesthetic preferences for animals correspond with the species’ presence in the worldwide zoos and influence the conservation priorities. Here, we investigated the relationship between the willingness of respondents to protect mammals and some attributed characteristics such as their aesthetic beauty. Further, several methodological aspects of measuring mammalian beauty were assessed. Animal beauty was associated not only with the respondents’ willingness to protect the species but also with its attributed dangerousness and usefulness. We found that the most preferred animals were carnivores and ungulates, whilst smaller species of rodents and afrosoricids were unpopular. The main characteristics determining that an animal will be ranked as beautiful were complex fur pattern and body shape. We demonstrated that the position of mammalian species along the ‘beauty’ axis is surprisingly stable, no matter the form (illustrations vs photographs), context of stimulus presentation (several number of stimuli per family vs one randomly selected species per family), or the method of beauty evaluation (relative order vs Likert’s scale).

Evolutionary Perspectives on Male Homosexuality: A Literature Review. Yasmina Mashmoushi, Mitan Mzouri

Evolutionary Perspectives on Male Homosexuality: A Literature Review. Yasmina Mashmoushi, Mitan Mzouri. Proceedings of Manitoba's Undergraduate Science and Engineering Research, Vol 4, issue 1, 2018, http://dx.doi.org/10.5203/pmuser.201841619

Abstract: This review provides a comprehensive coverage of the leading evolutionary hypotheses to date on male homosexuality (namely the sexual antagonism model, the tipping-point model, and the kin selection hypothesis). It does so by first (1), surveying prominent findings on the nature and biological causes of male homosexuality; second (2), discussing the effects of male homosexuality on individual fitness; and third (3), outlining the contending evolutionary theories on male homosexuality and critically evaluating each against current pertinent empirical evidence. This review reveals that male homosexuality is a complex, multifaceted phenomenon influenced by an interplay of genomic and environmental factors that may have had unique evolutionary trajectories. Thus, there is likely more than one evolutionary mechanism at play responsible for the maintenance of gay alleles in the human population. Current research largely supports the notion that gay alleles bestow fitness benefits on heterosexual carriers. The tipping-point model and sexual antagonism model, but not the kin selection hypothesis, are in line with current empirical evidence. Future research into the genomic underpinnings of sexual orientation in homosexual males and its genetic equivalents in heterosexual males and females may allow for further evaluation of these hypotheses.

Keywords: human evolution, evolutionary psychology, mating preferences, sexual orientation, homosexuality

---
The tipping-point model of male homosexuality, popularized byEdwardMiller, posits that the group of alleles that code for a homosexual orientation in gay men confer strong fitness benefits in heterosexual men by coding in them a certain level of psychological femininity68. According to Miller, if only a few of these alleles are inherited by males, their reproductive success is enhanced via the expression of attractive, albeit feminine traits such as kindness, empathy, andsensitivity68. However, if too many of these alleles are inherited by males, a tipping-point is reached, at which even their mate preferences become feminized68. Miller came up with a simplified version of his theory to better illustrate it. He asks the reader to imagine that there are five different genes that each help code for an individual's place along a masculine-feminine continuum. Each of these five genes have two respective alleles: one that pulls the individual to the masculine side of the continuum and one that pulls the individual to the feminine side of the continuum. According to his simplified model, if a man inherits all five of the "feminine-pulling alleles", he will be homosexual and if he inherits less than five,he will not. Homosexuality would continue to persist in the human populationif a strong reproductive advantage is conferred on individuals possessing some copies of these feminine-pulling alleles. According to Miller, a low doseo f these feminine-pulling  alleles significantly enhances a heterosexual male carrier's reproductive success. But in the less common, spontaneous occasion that a significantly large dose of these feminine-pulling alleles is inherited, the male carrier’s sexual orientation is altered and his fitness adversely affected. Nonetheless, these alleles would continue to persist in the population if they confer an overall reproductive advantage on thei rmale carriers68. Consistent with the tipping-point hypothesis, homosexual men are reported to be more sensitive, kind, and empathetic than heterosexual men,which have been characteristically deemed to be feminine attributes70. Furthermore, studies have found that a higher level of psychological femininity in straight men is associated with a greater number of female partners, suggesting that psychological femininity is attractive to women71,72. This could be because psychological femininity indicates a nurturing disposition which could help rear offspring. In another study, researchers predicted that if the tipping-point model of male homosexuality were correct, then heterosexual men with a homosexual maletwin should have more attractive feminine-pulling alleles and thus more opposite-sex partners than members of heterosexual twin pairs15. The findings of this large community-based twin study(N=4904)supported this prediction; heterosexual males with a homosexual male twin had significantly more children, significantly more opposite sex partners, and were significantly younger at their first age of intercourse than members of heterosexual male twin pairs (p<0.001)15. The results of these and similar studies have made the tipping-point model one of the leading evolutionary theories on male homosexuality to date67.

Another possibility is that the alleles responsible for male homosexuality code for psychologically or physically feminizing traits in both men and women21,67. Thes exual antagonism model suggests that an allele that is detrimental tothe fitnessof one sex could be maintained in the populationso long as it is beneficial to thefitness of the other sex21. An allele that make sits bearer attracted to men and more feminine provides an obvious reproductive advantage to women, but an obvious reproductive disadvantage to men21. This allele would code for same-sex attraction if it appears in a male's genome but would maintainanet evolutionary benefit if this occurs rarely21. There is asignificant amount of evidence for this theory. Numerous studies have found significantly greater fecundity in the female matrilineal relatives of homosexual men (i.e. their mothers, aunts and grand-mothers)as compared to heterosexual men 21,73,74,75. Some other studies have also found that the female relatives of homosexual males have significantly fewer abortions and gestational complications than the female relatives of heterosexual males12,74. Moreover, homosexual men have been found to have an excess of matrilineal but not patrilineal male homosexual relatives as compared to heterosexual men21,73. According to researchers, even a modest increase in the reproductive capacity of females carrying these gay alleles could easily account fort heir maintenance at high levels in the population21,76.

Individuals in a politically homogeneous social networking site environment were more likely to unfriend/hide the political rivals; liberals are more prone to unfriending, as are the educated; the young hide

Social networking site as a Political Filtering Machine: Predicting the Act of Political Unfriending and Hiding on Social Networking Sites. Joseph Yoo, Margaret Yee Man Ng, Thomas Johnson. The Journal of Social Media in Society, Vol 7, No 2 (2018), http://thejsms.org/tsmri/index.php/TSMRI/article/view/359

Abstract: Social networking sites (SNSs) seem to have become a political filtering machine that allows users to classify their online friends based on their political ideologies. Hiding and unfriending on social media has turned into being a political gesture, discriminating individuals with opposite political views on SNSs. Unfriending activities during the 2016 U.S. Presidential election and during the Hong Kong Umbrella Movement are two notable examples. Individuals have the tendency to consume politically congenial information and be surrounded by people who share the same views. The formation of echo chambers and the reason for relationship dissolution on SNSs can be explained by Social Identity Theory.

Through an online panel survey of 386 SNS users, this study examined how factors of political ideologies, social media and offline political participation and likeminded exposure on SNSs can predict hiding and unfriending/unfollowing on Twitter and Facebook. Results from ordinary least square (OLS) regression analysis revealed that if individuals had been in a politically homogeneous SNS environment, they were more likely to unfriend, suggesting the reinforcement of echo chambers in SNSs. Both social media and offline political participations predicted the dissociative, indicating that unfriending and hiding could be regarded as a new form of online political participation to engage in political affairs.

Keywords: Political participation, Hiding, Unfriending, Relationship dissolution, like-minded exposure

Friday, January 4, 2019

Artificial intelligence turns brain activity into speech

Artificial intelligence turns brain activity into speech. Kelly Servick. Jan. 2, 2019. https://www.sciencemag.org/news/2019/01/artificial-intelligence-turns-brain-activity-speech

For many people who are paralyzed and unable to speak, signals of what they'd like to say hide in their brains. No one has been able to decipher those signals directly. But three research teams recently made progress in turning data from electrodes surgically placed on the brain into computer-generated speech. Using computational models known as neural networks, they reconstructed words and sentences that were, in some cases, intelligible to human listeners.

None of the efforts, described in papers in recent months on the preprint server bioRxiv, managed to re-create speech that people had merely imagined. Instead, the researchers monitored parts of the brain as people either read aloud, silently mouthed speech, or listened to recordings. But showing the reconstructed speech is understandable is "definitely exciting," says Stephanie Martin, a neural engineer at the University of Geneva in Switzerland who was not involved in the new projects.

People who have lost the ability to speak after a stroke or disease can use their eyes or make other small movements to control a cursor or select on-screen letters. (Cosmologist Stephen Hawking tensed his cheek to trigger a switch mounted on his glasses.) But if a brain-computer interface could re-create their speech directly, they might regain much more: control over tone and inflection, for example, or the ability to interject in a fast-moving conversation.

The hurdles are high. "We are trying to work out the pattern of … neurons that turn on and off at different time points, and infer the speech sound," says Nima Mesgarani, a computer scientist at Columbia University. "The mapping from one to the other is not very straightforward." How these signals translate to speech sounds varies from person to person, so computer models must be "trained" on each individual. And the models do best with extremely precise data, which requires opening the skull.

Researchers can do such invasive recording only in rare cases. One is during the removal of a brain tumor, when electrical readouts from the exposed brain help surgeons locate and avoid key speech and motor areas. Another is when a person with epilepsy is implanted with electrodes for several days to pinpoint the origin of seizures before surgical treatment. "We have, at maximum, 20 minutes, maybe 30," for data collection, Martin says. "We're really, really limited."

The groups behind the new papers made the most of precious data by feeding the information into neural networks, which process complex patterns by passing information through layers of computational "nodes." The networks learn by adjusting connections between nodes. In the experiments, networks were exposed to recordings of speech that a person produced or heard and data on simultaneous brain activity.

Mesgarani's team relied on data from five people with epilepsy. Their network analyzed recordings from the auditory cortex (which is active during both speech and listening) as those patients heard recordings of stories and people naming digits from zero to nine. The computer then reconstructed spoken numbers from neural data alone; when the computer "spoke" the numbers, a group of listeners named them with 75% accuracy.

[recording: A computer reconstruction based on brain activity recorded while a person listened to spoken digits.
H. Akbari et al., doi.org/10.1101/350124]

Another team, led by neuroscientists Miguel Angrick of the University of Bremen in Germany and Christian Herff at Maastricht University in the Netherlands, relied on data from six people undergoing brain tumor surgery. A microphone captured their voices as they read single-syllable words aloud. Meanwhile, electrodes recorded from the brain's speech planning areas and motor areas, which send commands to the vocal tract to articulate words. The network mapped electrode readouts to the audio recordings, and then reconstructed words from previously unseen brain data. According to a computerized scoring system, about 40% of the computer-generated words were understandable.

[recording: Original audio from a study participant, followed by a computer recreation of each word, based on activity in speech planning and motor areas of the brain.
M. Angrick et al., doi.org/10.1101/478644]

Finally, neurosurgeon Edward Chang and his team at the University of California, San Francisco, reconstructed entire sentences from brain activity captured from speech and motor areas while three epilepsy patients read aloud. In an online test, 166 people heard one of the sentences and had to select it from among 10 written choices. Some sentences were correctly identified more than 80% of the time. The researchers also pushed the model further: They used it to re-create sentences from data recorded while people silently mouthed words. That's an important result, Herff says—"one step closer to the speech prosthesis that we all have in mind."

However, "What we're really waiting for is how [these methods] are going to do when the patients can't speak," says Stephanie Riès, a neuroscientist at San Diego State University in California who studies language production. The brain signals when a person silently "speaks" or "hears" their voice in their head aren't identical to signals of speech or hearing. Without external sound to match to brain activity, it may be hard for a computer even to sort out where inner speech starts and ends.

Decoding imagined speech will require "a huge jump," says Gerwin Schalk, a neuroengineer at the National Center for Adaptive Neurotechnologies at the New York State Department of Health in Albany. "It's really unclear how to do that at all."

One approach, Herff says, might be to give feedback to the user of the brain-computer interface: If they can hear the computer's speech interpretation in real time, they may be able to adjust their thoughts to get the result they want. With enough training of both users and neural networks, brain and computer might meet in the middle.

doi:10.1126/science.aaw5300

[Recordings at the link above at the beginning]

Check also Towards reconstructing intelligible speech from the human auditory cortex. Hassan Akbari, Bahar Khalighinejad, Jose L. Herrero, Ashesh D. Mehta & Nima Mesgaran. Scientific Reportsvolume 9, Article number: 874 (2019), https://www.nature.com/articles/s41598-018-37359-z


Photosynthesis may produce toxic by-products that reduce its efficiency; a transgenic plant efficiently recaptures the unproductive by-products of photosynthesis with less energy lost, plants grew ∼40% more

Synthetic glycolate metabolism pathways stimulate crop growth and productivity in the field. Paul F. South, Amanda  P. Cavanagh, Helen W. Liu, Donald R. Ort. Science  Jan 04 2019, Vol. 363, Issue 6422, eaat9077, DOI: 10.1126/science.aat9077

Fixing photosynthetic inefficiencies: In some of our most useful crops (such as rice and wheat), photosynthesis produces toxic by-products that reduce its efficiency. Photorespiration deals with these by-products, converting them into metabolically useful components, but at the cost of energy lost. South et al. constructed a metabolic pathway in transgenic tobacco plants that more efficiently recaptures the unproductive by-products of photosynthesis with less energy lost (see the Perspective by Eisenhut and Weber). In field trials, these transgenic tobacco plants were ∼40% more productive than wild-type tobacco plants.

Structured Abstract
INTRODUCTION: Meeting food demands for the growing global human population requires improving crop productivity, and large gains are possible through enhancing photosynthetic efficiency. Photosynthesis requires the carboxylation of ribulose-1,5-bisphosphate (RuBP) by ribulose-1,5-bisphosphate carboxylase-oxygenase (RuBisCO), but photorespiration occurs in most plants such as soybean, rice, and wheat (known as C3 crops) when RuBisCO oxygenates RuBP instead, requiring costly processing of toxic byproducts such as glycolate. Photorespiration can reduce C3 crop photosynthetic efficiency by 20 to 50%. Although various strategies exist for lowering the costs of photorespiration, chamber- and greenhouse-grown plants with altered photorespiratory pathways within the chloroplast have shown promising results, including increased photosynthetic rates and plant size.

RATIONALE: To determine if alternative photorespiratory pathways could effectively improve C3 field crop productivity, we tested the performance of three alternative photorespiratory pathways in field-grown tobacco. One pathway used five genes from the Escherichia coli glycolate oxidation pathway; a second pathway used glycolate oxidase and malate synthase from plants and catalase from E. coli; and the third pathway used plant malate synthase and a green algal glycolate dehydrogenase. All enzymes in the alternative pathway designs were directed to the chloroplast. RNA interference (RNAi) was also used to down-regulate a native chloroplast glycolate transporter in the photorespiratory pathway, thereby limiting metabolite flux through the native pathway. The three pathways were introduced with and without the transporter RNAi construct into tobacco, which is an ideal model field crop because it is easily transformed, has a short life cycle, produces large quantities of seed, and develops a robust canopy similar to that of other field crops.

RESULTS: Using a synthetic biology approach to vary promoter gene combinations, we generated a total of 17 construct designs of the three pathways with and without the transporter RNAi construct. Initial screens for photoprotection by alternative pathway function under high–photorespiratory stress conditions identified three to five independent transformants of each design for further analysis. Gene and protein expression analyses confirmed expression of the introduced genes and suppression of the native transporter in RNAi plants. In greenhouse screens, pathway 1 increased biomass by nearly 13%. Pathway 2 showed no benefit compared to wild type. Introduction of pathway 3 increased biomass by 18% without RNAi and 24% with RNAi, which were consistent with changes in photorespiratory metabolism and higher photosynthetic rates. Ultimately, field testing across two different growing seasons showed >25% increase in biomass of pathway 3 plants compared to wild type, and with RNAi productivity increased by >40%. In addition, this pathway increased the light-use efficiency of photosynthesis by 17% in the field.

CONCLUSION: Engineering more efficient photorespiratory pathways into tobacco while inhibiting the native pathway markedly increased both photosynthetic efficiency and vegetative biomass. We are optimistic that similar gains may be achieved and translated into increased yield in C3 grain crops because photorespiration is common to all C3 plants and higher photosynthetic rates under elevated CO2, which suppresses photorespiration and increases harvestable yield in C3 crops.

We test the reproducibility/generalisability of priming effects on risk attitudes: we find no systematic effect; fear does not appear to cause countercyclical risk aversion; positive affect makes participants take more risk

On the priming of risk preferences: The role of fear and general affect. Despoina Alempaki, Chris Starmer, Fabio Tufano. Journal of Economic Psychology, https://doi.org/10.1016/j.joep.2018.12.011

Highlights
•    We test the reproducibility/generalisability of priming effects on risk attitudes.
•    In a series of experiments, we sample over 1900 subjects from a diverse population.
•    We find no systematic effect of priming on individuals’ risk attitudes.
•    Fear does not appear to cause countercyclical risk aversion.
•    Positive affect makes participants take more risk.

Abstract: Priming is an established tool in psychology for investigating aspects of cognitive processes underlying decision making and is increasingly applied in economics. We report a systematic attempt to test the reproducibility and generalisability of priming effects on risk attitudes in a more diverse population than professionals and students, when priming using either a positive or a negative experience. We further test fear as the causal mechanism underlying countercyclical risk aversion. Across a series of experiments with a total sample of over 1900 participants, we are unable to find any systematic effect of priming on risk preferences. Moreover, our results challenge the role of fear as the mechanism underlying countercyclical risk aversion; we find evidence of an impact of general affect such that the better our participants feel, the more risk they take.

Pattern Analysis of World Conflicts over the past 600 years: War is a statistical phenomenon related to the network structure of the human society

Pattern Analysis of World Conflicts over the past 600 years. Gianluca Martelloni, Francesca Di Patti, Ugo Bardi. arXiv, Dec 2018. https://arxiv.org/abs/1812.08071

Abstract: We analyze the database prepared by Brecke (Brecke 2011) for violent conflict, covering some 600 years of human history. After normalizing the data for the global human population, we find that the number of casualties tends to follow a power law over the whole data series for the period considered, with no evidence of periodicity. We also observe that the number of conflicts, again normalized for the human population, show a decreasing trend as a function of time. Our result agree with previous analyses on this subject and tend to support the idea that war is a statistical phenomenon related to the network structure of the human society.


Advisors interpersonally penalize those who do not follow their advice; penalize seekers more than non-expert advisors; interpersonally penalize seekers consulting multiple advisors

Seeker beware: The interpersonal costs of ignoring advice. Hayley Blunden et al. Organizational Behavior and Human Decision Processes, Volume 150, January 2019, Pages 83-100. https://doi.org/10.1016/j.obhdp.2018.12.002

Highlights
•    Advisors interpersonally penalize those who do not follow their advice.
•    Expert advisors penalize seekers more than non-expert advisors.
•    Advisors interpersonally penalize seekers consulting multiple advisor.
•    Advisors to “multiple advice-seekers” perceive their advice will be disregarded.
•    Advice seekers view the purpose of seeking advice as gathering information.
•    Advisors (vs. seekers) view their purpose as more to provide direction.
•    Seekers should consider interpersonal goals alongside decision accuracy ones.

Abstract: Prior advice research has focused on why people rely on (or ignore) advice and its impact on judgment accuracy. We expand the consideration of advice-seeking outcomes by investigating the interpersonal consequences of advice seekers’ decisions. Across nine studies, we show that advisors interpersonally penalize seekers who disregard their advice, and that these reactions are especially strong among expert advisors. This penalty also drives advisor reactions to a widely-recommended advice-seeking strategy: soliciting multiple advisors to leverage the wisdom of crowds. Advisors denigrate and distance themselves from seekers who they learn consulted others, an effect mediated by perceptions that their own advice will be disregarded. Underlying these effects is an asymmetry between advisors’ and seekers’ beliefs about the purpose of the advice exchange: whereas advisors believe giving advice is more about narrowing the option set by providing direction, seekers believe soliciting advice is more about widening the option set by gathering information.

How husbands and wives report their earnings when she earns more: Inflating their reports of husbands’ earnings & deflating their reports of wives’ earnings

Manning up and womaning down: How husbands and wives report their earnings when she earns more. Marta Murray-Close and Misty L. Heggeness, US Census Bureau, Working Paper Number SEHSD-WP2018-20, https://www.census.gov/library/working-papers/2018/demo/SEHSD-WP2018-20.html

Abstract: Do gendered social norms influence survey reports of “objective” economic outcomes? This paper compares the earnings reported for husbands and wives in the Current Population Survey with their “true” earnings from administrative income-tax records. Estimates from OLS regressions show that survey respondents react to violations of the norm that husbands earn more than their wives by inflating their reports of husbands’ earnings and deflating their reports of wives’ earnings. On average, the gap between a husband’s survey and administrative earnings is 2.9 percentage points higher if his wife earns more than he does, and the gap between a wife’s survey and administrative earnings in 1.5 percentage points lower if she earns more than her husband does. These findings suggest that gendered social norms can influence survey reports of seemingly objective outcomes and that their impact may be heterogeneous not just between genders but also within gender.

We focus on specific trading days on which investors are primed for honest behavior (Yom Kippur); the patterns found may reflect the increased awareness to honesty

The High Holidays: Psychological Mechanisms of Honesty in Real-Life Financial Decisions. Doron Kliger, Mahmoud Qadan. Journal of Behavioral and Experimental Economics, Journal of Behavioral and Experimental Economics, https://doi.org/10.1016/j.socec.2018.12.012

Highlights
•    We focus on specific trading days on which investors are primed for honest behavior
•    Returns during these ten days (High Holidays) are abnormally low; and
•    Implied volatility, as well as realized volatility estimates are abnormally high
•    These systematic patterns may reflect the increased awareness to honesty
•    We suggest a simple trading rule that investors may utilize during these days

ABSTRACT: Research in psychology has established that activation of religious ideas affects individuals’ behavior. We hypothesize that religious and honesty mechanisms activated on the High Holidays, the ten days before Yom Kippur, when people seek repentance, amplify people's anxiety and affect their financial decision-making. We find that returns during the High Holidays are abnormally low; implied volatility, measured by VIX and VXO, as well as realized volatility estimates, are abnormally high; and the abnormal increase in implied volatility overshoots future volatility. Using these results, we devise a simple trading rule that investors may consider to maximize returns during the High-Holidays period.

Thursday, January 3, 2019

Targets of negative gossip experienced guilt, especially with low core self-evaluations & caused repair intentions; & anger, especially for targets with high reputational concerns, & caused retaliation intentions

Self-Evaluative and Other-Directed Emotional and Behavioral Responses to Gossip About the Self. Elena Martinescu, Onne Janssen and Bernard A. Nijstad. Front. Psychol., Jan 04 2019, https://doi.org/10.3389/fpsyg.2018.02603

Gossip, or informal talk about others who are not present, is omnipresent in daily interactions. As such, people who are targeted are likely to hear some gossip about themselves, which may have profound implications for their well-being. We investigated the emotions and behavioral intentions of people who hear performance-related gossip about themselves. Based on the affective events theory, we predicted that gossip incidents have strong emotional consequences for their targets and that these emotional responses trigger different behaviors. Two scenario studies (N1 = 226, Mage = 21.76; N2 = 204, Mage = 34.11) and a critical incident study (N = 240, Mage = 37.04) compared targets' responses to positive and negative gossip. Whereas, targets of positive gossip experienced positive self-conscious emotions (e.g., pride), targets of negative gossip experienced negative self-conscious emotions (e.g., guilt), especially when they had low core self-evaluations. In turn, these negative self-conscious emotions predicted repair intentions. Positive gossip also led to positive other-directed emotions (e.g., liking), which predicted intentions to affiliate with the gossiper. Negative gossip, however, also generated other-directed negative emotions (e.g., anger), especially for targets with high reputational concerns, which in turn predicted retaliation intentions against the gossiper. This pattern of emotional reactions to self-relevant gossip was found to be unique and different from emotional reactions to self-relevant feedback. These results show that gossip has self-evaluative and other-directed emotional consequences, which predict how people intend to behaviorally react after hearing gossip about themselves.

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These findings help understand target's emotional and behavioral reactions to gossip as functional. Repair behaviors might be an adaptive response to negative gossip, helping targets avoid further deterioration of their self-views and social relationships. Intentions to retaliate against gossipers, who have harmed targets' social capital may also be functional in deterring future reputational attacks. Furthermore, positive gossip confirms valuable attributes or goal accomplishment and serves targets' fundamental need for a positive self-view (Kunda, 1990; Sedikides and Strube, 1997), potentially motivating individuals to strive for future achievements and status (Tracy et al., 2010). Moreover, positive gossip is functional in fostering a social bond between targets and gossipers, who are likely to be perceived as supportive and trustworthy allies.

Our work also clarifies that people have distinct emotional reactions to gossip and feedback about themselves, thereby indicating that the two types of self-relevant information have distinct implications for the targets' self-evaluation and reputation. Negative feedback generated higher self-conscious negative emotions and repair intentions than negative gossip, possibly because formal feedback is communicated for improvement and development purposes and increases one's sense of self-awareness and accountability. In contrast, because negative gossip is spread in one's absence (Foster, 2004) and is not clearly intended to advance performance, it may be more easily discounted by targets, thereby generating lower self-conscious negative emotions and repair intentions. Furthermore, gossip led to higher other-directed negative emotions and to lower other-directed positive emotions than feedback, suggesting that gossip is perceived as more malignant or less benign than formal feedback, possibly because it is communicated behind one's back. These results indicate that gossip is a mechanism that parallels formal communication channels in organizations and regulates group members' behavior and interpersonal relations.

In addition to the hypothesized reactions of gossip targets, the analyses revealed other effects. Consistent across Studies 1 and 3, self-conscious positive emotions predicted retaliation intentions. Positive gossip may enable targets to evaluate themselves as better than others [i.e., hubristic pride, (Tracy et al., 2010)], possibly generating retaliation intentions, because hubristic pride instigates people to establish a reputation of dominance and assert power through aggression (Tracy et al., 2010). However, other-directed positive emotions induced by positive gossip decreased retaliation intentions (Study 3) and increased repair intentions (Studies 1 and 2). Thus, positive gossip also made targets feel included, thereby motivating prosocial and reducing antisocial behaviors. As such, positive gossip generated both retaliation and affiliation intentions by arousing self-conscious and other-directed positive emotions, respectively. Furthermore, negative gossip targets were more likely to affiliate with the gossiper due to negative self-conscious (Studies 2 and 3) and other-directed emotions (Study 3). Targets who feel guilty or ashamed may see gossipers as expert observers of their shortcomings [expert power, (Kurland and Pelled, 2000)] and seek contact to obtain support or advice. In contrast, those who are angry with gossipers may seek future contact to disprove the negative gossip, or to search for retaliation opportunities.

[...]

In line with the AET (Weiss and Cropanzano, 1996), our findings have shown that the prosocial (repair and affiliation) and antisocial (retaliation) behaviors of gossip targets are driven by affective processes, and that predispositions (CSE and CR) moderate the affective and behavioral reactions to gossip events. Future research may additionally investigate the role of other cognitive or motivational processes in shaping gossip targets' behavior, or whether gossip about the self may be experienced in a non-affective manner. Furthermore, given the differential effects of gossip vs. feedback found in Study 2, it may be interesting for the AET to distinguish between more formal vs. informal affective events at work. Our results suggest that affective reactions may differ where formal evaluations vs. gossip are concerned, and perhaps similar effects can be expected for other types of (formal vs. informal) communication at work, such as official, written communication compared to rumors.

The positive emotions generated by positive gossip are universally pleasing and can easily co-occur, as was the case in all three studies: targets were simultaneously happy with themselves and with gossipers. However, different association patterns are possible for the negative emotions aroused by negative gossip. On the one hand, gossip targets may exclusively feel negative emotions directed at the gossipers for their harmful gossiping behavior, possibly rejecting their own faults to protect their self-views (Kunda, 1990). On the other hand, targets may feel self-conscious about their shortcomings and blame gossipers for sharing the negative gossip. In Studies 1 and 2, self-conscious and other-directed negative emotions were not correlated when gossip valence was accounted for, but they were positively correlated in Study 3, suggesting that boundary conditions may apply. In Study 3 we indeed showed that the arousal of negative self-conscious and other-directed emotions depends on self-directed (CSE) and other-directed (CR) dispositional factors, respectively. Furthermore, self-conscious and other-directed negative emotions predicted whether gossip targets had prosocial (reparation) or antisocial (retaliation) intentions.

Increased market orientation causes a significant increase in discoveries of natural resources

The shifting natural wealth of nations: The role of market orientation. Rabah Arezki, Frederick van der Ploeg, Frederik Toscani. Journal of Development Economics, https://doi.org/10.1016/j.jdeveco.2018.12.002

Highlights
•    We explore the effect of market orientation on (known or available) natural resource wealth.
•    A novel dataset combines world-wide major hydrocarbon and mineral discoveries.
•    Empirical estimates show that increased market orientation causes a significant increase in discoveries of natural resources.
•    We call into question the commonly held view that known or available natural resource endowments are exogenous.

Abstract: This paper explores the effect of market orientation on (known or available) natural resource wealth using a novel dataset of world-wide major hydrocarbon and mineral discoveries. Our empirical estimates based on a large panel of countries show that increased market orientation causes a significant increase in discoveries of natural resources. In a thought experiment where economies in Latin America and sub-Saharan Africa remain closed, they would have only achieved one quarter of the actual increase in discoveries they have experienced since the early 1990s. Our results call into question the commonly held view that known or available natural resource endowments are exogenous.

Danish high-quality administrative data: Individuals with relatively low time discounting are persistently positioned higher in the wealth distribution

Time Discounting, Savings Behavior, and Wealth Inequality. Thomas Epper, Ernst Fehr, Helga Fehr-Duda, Claus Thustrup Kreiner, David D. Lassen, Søren Leth-Petersen, Gregers Nytoft-Rasmussen. AEA Wealth Inequality & Wealth Taxation Paper Session Jan 2019, https://daviddlassen.github.io/publication/wealthineq/

Abstract: The distribution of wealth in society is very unequal and has important economic and political consequences. According to standard life-cycle savings theory, differences in time discounting behavior across individuals can play an important role for their position in the wealth distribution. Empirical testing of this hypothesis has been difficult because of serious data limitations. We overcome these limitations by linking an experimental measure of time discounting for a large sample of middle-aged individuals to Danish high-quality administrative data with information about their real-life wealth over the life-cycle as well as a large number of background characteristics. The results show that individuals with relatively low time discounting are persistently positioned higher in the wealth distribution. The relationship is of the same magnitude as the association between years of education and the position in the wealth distribution, and it robustly persists after controlling for a large number of theoretically motivated confounders such as education, risk aversion, school grades, income, credit constraints, initial wealth, and parental wealth. These findings support the view that individual differences in time discounting affect individuals’ positions in the wealth distribution through the savings channel.

The increasing value of time raises the cost of commuting & exogenously increases the demand for central locations by high-skilled workers, magnified by endogenous amenity improvement

Su, Yichen, The Rising Value of Time and the Origin of Urban Gentrification (December 12, 2018). http://dx.doi.org/10.2139/ssrn.3216013

Abstract: I estimate a spatial equilibrium model to show that the rising value of high-skilled workers' time is an important driving force behind the gentrification of American central cities. I show that the increasing value of time raises the cost of commuting and exogenously increases the demand for central locations by high-skilled workers. While change in value of time is an initial force behind gentrification, its effect is substantially magnified by endogenous amenity improvement. The model implies that welfare inequality in the recent decades increases by more than the rise in earnings inequality if the forces behind gentrification are considered.

Keywords: urban, gentrification, spatial equilibrium, value of time, neighborhood, amenities, rent, housing supply, urban revival, inequality, work hours, long-hour premium, overtime
JEL Classification: J22, R12, R2, R31, R30, R31

The Effect of Aggressive Fantasy on Subjective Well-Being: Stuck on the Train of Ruminative Thoughts, Diminishing Well-Being

Stuck on the Train of Ruminative Thoughts: The Effect of Aggressive Fantasy on Subjective Well-Being. Kai-Tak Poon, Wing-Yan Wong. Journal of Interpersonal Violence, https://doi.org/10.1177/0886260518812796

Abstract: Previous studies have focused almost exclusively on identifying the antecedents of aggression and violence; as such, there are virtually no experimental data about the psychological consequences of fantasizing aggressive and violent actions. The present experiment aimed to fill this significant informational void in the literature by testing whether aggressive fantasy would influence people’s rumination tendency and subjective well-being. We hypothesized that aggressive fantasy would make people more likely to ruminate, which would thereby lower their subjective well-being. To test this prediction, we recruited a sample of participants, who were adults in the United States (overall valid N = 113; 39 men; mean age = 36.27, SD = 11.27), and they were randomly assigned to either the aggressive fantasy condition or the control condition. At the beginning of the experiment, participants were asked to think of a person they despised and describe the characteristics of the despised person. Next, participants in the aggressive fantasy condition fantasized aggressive and violent actions toward the despised target, while participants in the control condition fantasized a control experience. Finally, their state rumination and subjective well-being were assessed. The results showed that, relative to participants who did not fantasize aggression, those who engaged in aggressive fantasy reported higher levels of rumination and lower levels of subjective well-being. Further analysis showed that enhanced rumination significantly mediated the effect of aggressive fantasy on subjective well-being. The present findings contribute to the literature by providing new insights into the psychological consequences of aggressive and violent responses and the underlying mechanism.

Keywords: aggressive fantasy, aggression, rumination, subjective well-being, antisocial tendency

Fetal Origins of Mental Disorders? A Negative Answer Based on Mendelian Randomization

Fetal Origins of Mental Disorders? An Answer Based on Mendelian Randomization. Subhi Arafat and Camelia C. Minică. Twin Research and Human Genetics, Volume 21, Issue 6, December 2018 , pp. 485-494, https://doi.org/10.1017/thg.2018.65

Abstract: The Barker hypothesis states that low birth weight (BW) is associated with higher risk of adult onset diseases, including mental disorders like schizophrenia, major depressive disorder (MDD), and attention deficit hyperactivity disorder (ADHD). The main criticism of this hypothesis is that evidence for it comes from observational studies. Specifically, observational evidence does not suffice for inferring causality, because the associations might reflect the effects of confounders. Mendelian randomization (MR) — a novel method that tests causality on the basis of genetic data — creates the unprecedented opportunity to probe the causality in the association between BW and mental disorders in observation studies. We used MR and summary statistics from recent large genome-wide association studies to test whether the association between BW and MDD, schizophrenia and ADHD is causal. We employed the inverse variance weighted (IVW) method in conjunction with several other approaches that are robust to possible assumption violations. MR-Egger was used to rule out horizontal pleiotropy. IVW showed that the association between BW and MDD, schizophrenia and ADHD is not causal (all p > .05). The results of all the other MR methods were similar and highly consistent. MR-Egger provided no evidence for pleiotropic effects biasing the estimates of the effects of BW on MDD (intercept = -0.004, SE = 0.005, p = .372), schizophrenia (intercept = 0.003, SE = 0.01, p = .769), or ADHD (intercept = 0.009, SE = 0.01, p = .357). Based on the current evidence, we refute the Barker hypothesis concerning the fetal origins of adult mental disorders. The discrepancy between our results and the results from observational studies may be explained by the effects of confounders in the observational studies, or by the existence of a small causal effect not detected in our study due to weak instruments. Our power analyses suggested that the upper bound for a potential causal effect of BW on mental disorders would likely not exceed an odds ratio of 1.2.


Processes operating in the crime location choices between body‐disposing & non‐body‐disposing serial killers, & between sexual & acquisitive serial killers in Germany

Crime location choices: A geographical analysis of German serial killers. John Synnott et al. Journal of Investigative Psychology and Offender Profiling, https://doi.org/10.1002/jip.1521

Abstract: The present study examined whether there are different processes operating in the crime location choices between body‐disposing and non‐body‐disposing serial killers and between sexual serial killers and acquisitive serial killers. A sample of 49 series of solved German serial killings is used to examine the differences in travelled distances between these groups of killers. Nonparametric tests revealed that body‐disposing and non‐body‐disposing serial killers and sexual and acquisitive serial killers did not constitute subgroups of serial killers regarding their spatial behaviour. The results suggest that the compared groups are subjected to the same factors that influence their travelled distances. Furthermore, the possible role of planning and anticipated emotions in crime location choices of serial killers is discussed, as well as the limitations of the study and recommendations for future research.

Human children but not chimpanzees make irrational decisions driven by social comparison: Uniquely human social skills & motivations do not necessarily lead to more prosociality or cooperation

Human children but not chimpanzees make irrational decisions driven by social comparison. Esther Herrmann, Lou M. Haux, Henriette Zeidler and Jan M. Engelmann. Proceedings of the Royal Society B: Biological Sciences, January 2019, Volume 286, Issue 1894. https://doi.org/10.1098/rspb.2018.2228

Abstract: Human evolutionary success is often argued to be rooted in specialized social skills and motivations that result in more prosocial, rational and cooperative decisions. One manifestation of human ultra-sociality is the tendency to engage in social comparison. While social comparison studies typically focus on cooperative behaviour and emphasize concern for fairness and equality, here we investigate the competitive dimension of social comparison: a preference for getting more than others, expressed in a willingness to maximize relative payoff at the cost of absolute payoff. Chimpanzees and human children (5–6- and 9–10-year-olds) could decide between an option that maximized their absolute payoff (but put their partner at an advantage) and an option that maximized their relative payoff (but decreased their own and their partner's payoff). Results show that, in contrast to chimpanzees and young children, who consistently selected the rational and payoff-maximizing option, older children paid a cost to reduce their partner's payoff to a level below their own. This finding demonstrates that uniquely human social skills and motivations do not necessarily lead to more prosocial, rational and cooperative decision-making.

High mutual cooperation rates in rats learning reciprocal altruism: This finding allows to infer that the learning of reciprocal altruism has early appeared in evolution

High mutual cooperation rates in rats learning reciprocal altruism: The role of payoff matrix. Guillermo E. Delmas, Sergio E. Lew, B. Silvano Zanutto. PLOS One, Jan 2 2019. https://doi.org/10.1371/journal.pone.0204837

Abstract: Cooperation is one of the most studied paradigms for the understanding of social interactions. Reciprocal altruism -a special type of cooperation that is taught by means of the iterated prisoner dilemma game (iPD)- has been shown to emerge in different species with different success rates. When playing iPD against a reciprocal opponent, the larger theoretical long-term reward is delivered when both players cooperate mutually. In this work, we trained rats in iPD against an opponent playing a Tit for Tat strategy, using a payoff matrix with positive and negative reinforcements, that is food and timeout respectively. We showed for the first time, that experimental rats were able to learn reciprocal altruism with a high average cooperation rate, where the most probable state was mutual cooperation (85%). Although when subjects defected, the most probable behavior was to go back to mutual cooperation. When we modified the matrix by increasing temptation rewards (T) or by increasing cooperation rewards (R), the cooperation rate decreased. In conclusion, we observe that an iPD matrix with large positive reward improves less cooperation than one with small rewards, shown that satisfying the relationship among iPD reinforcement was not enough to achieve high mutual cooperation behavior. Therefore, using positive and negative reinforcements and an appropriate contrast between rewards, rats have cognitive capacity to learn reciprocal altruism. This finding allows to infer that the learning of reciprocal altruism has early appeared in evolution.


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High mutual cooperation rates in rats learning reciprocal altruism: The role of payoff matrix

High mutual cooperation rates in rats learning reciprocal altruism: The role of payoff matrix

  • Guillermo E. Delmas, 
  • Sergio E. Lew, 
  • B. Silvano Zanutto
PLOS
x



Introduction


Altruism is a behavior by an individual that may be to his disadvantage but benefits others individuals. At first sight, Darwin’s natural selection theory does not explain altruistic behavior. Theories have been proposed to account altruist behavior: kin selection [1], group selection and reciprocal altruism [2] among others. In the reciprocal altruism theory, the loss experienced by an individual for being altruist returns later on behalf of the reciprocal partner. Thus, in the long term, being altruist becomes the most useful strategy. In this regard, Triver’s theory of reciprocal altruism explains how natural selection favors reciprocal altruism between non-related individuals. Perhaps the most insightful example of such behavior is the one observed among vampire bats, where individuals share blood with others who have previously shared their food [3].

Since 1971, Iterated Prisoner’s Dilemma (iPD) has been a useful tool to study reciprocal altruism [4]. In the iPD, two players must choose between two possible behaviors: to cooperate or to defect. Rewards and punishments are defined in a 2x2 payoff matrix. When the game is played indefinitely, which is its iterated version, mutual cooperative behavior is favored. When played once, to defect is the best strategy [5]. However, when the game runs indefinitely, evolutionary stable strategies (ESS) emerge [67] and, under certain constraints imposed to the payoff matrix, mutual cooperation appears as the best strategy whenever reciprocity is maintained (Pareto Optimum). Among a huge number of reciprocal strategies, tit for tat is one of the most simple ones [8]. It is based on two simple rules: to cooperate in the first trial and, in the following, to do what the other player (opponent) did in the last trial.

Among many reciprocal behaviors, reciprocity and reciprocal altruism were well documented in several species. Although cooperation is needed to succeed in both reciprocity and reciprocal altruism, the latter adds the possibility of obtaining reward by defecting an opponent. Some experiments show reciprocal altruism behavior by means of iPD paradigm in different ways, but the results were either low levels of cooperation [9] or depended on a treatment that enhanced cooperation preference (mutualism matrix) [1012]. Direct reciprocity, which is established between two individuals, has been observed in monkeys [1315] and in rats [1619]. While food quality seemed to impact on cooperative behavior, a key factor to obtain reliable cooperation levels was the opponent’s behavior. In this sense, individuals tended to be more cooperative with opponents that had cooperated in the past. However, when reciprocal altruism is studied, differences between species come to light. Thus, while reciprocal altruism has been proven in monkeys, birds and rats failed to reach high levels of cooperation, even for complex combinations of rewards and punishments in the payoff matrix and treatments to induce preference [910122023]. The reasons why some species do not learn reciprocal altruism remain obscure. A possible explanation is that animals are not able to discriminate low contrast reward contingencies. Indeed, it has been shown that rats fail to discriminate the amount of reward when the number of reward units is larger than three [2426]. In this work, we designed an iPD setup to maximize the contrast among reinforcers. The amounts of pellets were chosen in order to minimize positive reinforcement earned in each trial and to keep rats motivated (hungry), [27]. In order to evaluate if animals developed ALLC strategy by place preference (after animals learned iPD) they were trained on reversal. We also evaluated reward maximization studying how the payoff matrix components promote or disrupt altruistic behavior.

Materials and methods


Subject


We used thirty male Long-Evans rats (weight 300-330g and two months old) provided by the IBYME-CONICET, divided in two experiments. In the first one, eighteen rats (twelve experimental and six opponent), and in the second, twelve rats (six experimental and six opponent). Experimental subjects were housed in pairs (to allow social interaction), and opponent rats were housed individually. All rats were food restricted and maintained at 90-95% for experimental subjects, and 80-85% for opponents of free feeding body weight, all with tap water available ad libitum. The housing room was at 22°C ± 2°C and 12/12 h light/dark cycle (with lights on at 9 am). Pre-training was performed on a single standard operant chamber (MED associates Inc., USA) equipped with two stimulus light and retractable levers below the light and feeders. Also the chambers were inside an anechoic chamber with white noise (with a flat power spectral density). The iPD experiments were performed in ad hoc dual chamber equipped with levers, lights and feeders (Fig 1A). The chambers were connected by windows allowing rats to make olfactory and eye contact. The lever’s height was 80% of maximum height of the forepaws while rearing [27]. The dual chamber is shown in supplementary material (see S2 Fig). At the end of daylight, supplementary food was provided to allow rats to maintain body weight.

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Fig 1. High level of cooperation in iPD.
(A) Dual operant box diagram and the matrix with positive(blue) and negative(red) reinforcement is shown. The iPD game had four possible states: R(reward) mutual cooperation, P(punishment) mutual defection, T(temptation) in which subject defected and opponent cooperated and S(sucker) subject cooperated and opponent defected. The opponent´s light was driven in order to perform a Tit for tat strategy. (B,C) Time-course of cooperation and timeout rate along the last 23 games sessions. In the last 5 sessions, the mean ± sem of cooperation was 0.86 ± 0.05 and timeout was 0.23 ± 0.08. (D) Total reward versus timeout for all animals (color bar means cooperation mean). Each animal was compared with the regression line fit to a population with cooperation level set to 60% (black continuous line). The higher the cooperation levels, the larger the total reward and the lower the total timeout. (E) Markov Chain diagram shows the probabilities of transition between states (p(c|T−1) = 0.76, p(c|R−1) = 0.85, p(c|S−1) = 0.93, p(c|P−1) = 0.87). The arrow represents transitions: driven by cooperation in blue, and driven by defection in red (the arrow thickness is proportional to transition probability). Below, bars show occupancy ratio when cooperation reaches stability. Probabilities were: p(R) = 0.76, p(T) = 0.1, p(P) = 0.04, p(S) = 0.1. Asterisks denote significant differences from multiple comparisons using one-way ANOVA and Bonferroni correction. (F) Evolution cooperation rate before and after reversal. Graphs show a moving average with samples of 3 sessions (the mean and sem from reversal on the last five sessions was 0.87 ± 0.04).

Pre-experimental training


All rats had a shaping procedure to learn the response (press a lever) to get a reinforcement (pellets). To prevent animals from choosing a lever place over the other, they learned to get reward from both sides by changing the side of conditioned stimulus. The side was changed after eight trials. All rats learned to press the correct lighting lever after four sessions. Each rat was trained in 2 sessions per day, each trial began with the inter-trial interval (ITI) during 5 seconds, it was followed by the conditioning stimulus (light) for either 45 seconds or until a lever was pressed. One second before food is delivered, the feeder was lighted. In the opponent’s training, they learned to press the lever when the light was on. In the task, the side of the active lever was chosen pseudo-randomly (allowing the same side no more than four times). The opponent subject had to perform a fix ratio treatment up to FR = 5 to get rewards.

Experiment


To study the reciprocal altruism in an iterated Prisoner’s Dilemma game (iPD), we used a payoff matrix with positive and negative reinforcements. Positive reinforcements were pellets (Bio-Serv 45 mg Dustless Precision Pellets) and negative reinforcement was timeout (a fix delay in starting a new trial). The payoff of the experimental subject was according to the matrix, and the opponent’s payoff was 1 pellet when the correct lighted lever was pressed. For the opponent, when the incorrect lever was pressed, there was no contingency and no pellet was delivered. The trial finishes after 45 seconds elapsed, or when the correct lever is pressed. The iPD game has four possible occupancy states where experimental and opponent individual behaviors can be as follows: both cooperate (mutual cooperation, R), both do not cooperate (mutual defection, P), experimental subject does not cooperate when the opponent cooperates (T), and experimental cooperates when the opponent does not cooperate (S). The amount of pellets preference was previously tested on a discrimination test, showing that rats prefer 2 pellets rather than 1 pellet (data not showed). We performed two sessions per day and each session had 30 trials. Each experimental subject was trained with the same opponent. The training was finished after five consecutive sessions with no changes in the cooperation rate. We defined cooperation (C) and defection (D) lever in the iPD box. The single iPD trial procedure was as follows: (1) ITI time, (2) then, the light (CS) was turned on, (3) after this, both rats made their responses, the light was turned off and the reinforcement was delivered according to a payoff matrix, (4) if positive reinforcement was assigned, the feeder’s light was turned on, and a second later a reward was delivered. The opponent’s Conditioned Stimulus (light) was controlled following a Tit for tat strategy. The opponent received a pellet after pressing three times the lever (FR = 3, so as to be enough time in front of the window until the experimental subject choose a lever). If negative reinforcement (timeout) was assigned, delay time started, and the opponent subject got a pellet reward. (5) After either five seconds eating time expired or timeout was completed, a new trial started. In the first experiment the payoff matrix was: 1 pellet for mutual cooperation (PR = 1), 2 pellets when the experimental subject defected and the opponent cooperated (PT = 2), 4 seconds of timeout for mutual defection (PP = 4seconds), and 8 seconds of timeout when the experimental subject cooperated and the opponent defected (PS = 8). At the end of these experiments, the four rats with the best performance in cooperation were trained in a reversion treatment (see Fig 1F). When rats were trained on reversal, the sides of C and D lever were interchanged in subject and opponent chambers. In that sense, if animals developed a place-preference behavior, they will not learn the new side in order to maximize reward. In the second experiment we used six naive experimental rats on a different payoff matrix with greater temptation (PR = 1, PT = 3, PP = 4, PS = 8). After training, we divided rats in two groups, depending on cooperation levels. The first group (Treat 2A) with high cooperation rate was trained with the payoff matrix (PR = 1, PT = 5, PP = 4, PS = 8) with greater temptation for T state (Treat 3A). The other group (with low cooperation rate, Treat 2B) was trained with the matrix (PR = 2, PT = 3, PP = 4, PS = 8, Treat 3B) that enhances cooperative behavior (in comparison with (PR = 1, PT = 3, PP = 4, PS = 8), but with low contrast between positive rewards (see Table 1). All experimental procedures were approved by the ethics committee of the IByME-CONICET and were conducted according to the NIH Guide for Care and Use of Laboratory Animals.2.1 Subjects and Housing.

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Table 1. Data summary.
Treatment 1: testing of high cooperation and reversion. Treatment 2 and 3: effect in cooperation by change of pay-off matrix. The matrix changed over the group with same word (A or B).

Statistic.


All statistical analyses were performed using statistics library from open source software Octave and MATLAB. We pooled the data from the last five sessions where cooperation rate was stable (to calculate cooperation rate we counted the number of times a rat chose the cooperation lever per session). We compared individual’s means of cooperation along treatment using a two-sided Wilcoxon rank sum test. To test whether the probability of cooperation after each outcome (T, R, P or S) was different from chance (0.5), we performed a Chi-square goodness of fit test with Bonferroni corrected value of 0.05/n. To compare mean rate of the different outcomes for each game, we performed an ANOVA two tails test. When significant Î± = 0.05, multiple post-hoc pairwise comparative tests were performed with Bonferroni corrected value of Î± = 0.0125. The individual’s decision rules can be described by the components of transition vectors and Markov Chain diagram. The transition vector was made up of probabilities of cooperation when the previous trials resulted in state p(c|R−1), T(temptation) p(c|T−1), S(sucker) p(c|S−1) or P(punishment), p(c|P−1) respectively. If every component of this vector is 0.5, the agent’s decision rule is random mode. Markov Chain diagram show the graphic representation of the complete decision making rule for each rat.

Results


We trained twelve rats in iPD against an opponent that plays Tit for tat strategy. Tit for tat is based on two simple rules: to cooperate in the first trial and, in the following, to do what the other player (opponent) did in the last trial. Fig 1A shows a schema of the different choices a subject can do in each trial. Thus, when the subject cooperates, it receives one pellet (PR) or eight seconds timeout (PS) depending on whether the opponent choice was to cooperate or to defect. On the other hand, when the subject defects, it receives 2 pellets (PT) or four seconds timeout (PP), according to whether the opponent choice was to cooperate or to defect respectively. The criteria for cooperation was an established preference for pressing C lever (cooperation) over D lever (defection) in more than 60% of the trials for five or more consecutive sessions. Eight out of twelve animals learned to cooperate (cooperation rate 0.86 ± 0.05, mean ± s.e.m), reaching criteria in 30 ± 4 sessions (mean ± s.e.m). In Fig 1B, we show the mean cooperation levels for those animals during the last twenty three sessions before reaching criteria. The inset in Fig 1B shows the mean cooperation level for each animal during the last five training sessions. As a consequence of the increase in cooperation levels, the average total timeout per session decreased as training progressed (0.23 ± 0.08, mean ± sem, see Fig 1C).

Due to the fact that different sequences of lever pressing can give the same amount of reward and/or timeout independently of the cooperation level, we analyzed the relationship between total reward and timeout for each animal in comparison to a simulated population. A regression line was fit to a population of 100,000 simulated individuals with cooperation level set to 60%, (see Fig 1D). Each simulated individual had one different strategy and each one was a combination of thirty C and D choices (session length). An individual that plays an iPD game with 60% of its choices in C will be near to the line, regardless of its strategies. As it can be seen in the figure, for the cooperator group when the cooperation level increases, the larger are the total reward, and the lower the total timeout. For the non cooperator group placed in the opposite side of the figure, it can be seen that both cooperation and reward were low and timeout was high. The regression line at 60% of cooperation separates both groups (marked with a red circle in the Fig 1D). This shows that no behavior with low level of cooperation (subgroup in blue range) can obtain both high level of reward and small amount of timeout as in the cooperative group. The average strategies of both group can be represented by Markov model diagram. We built one Markov model for the group of cooperative animals (see Fig 1E) averaging occupancy state rate and transition probabilities in the group. In the iPD there are four possible occupancy states where experimental and opponent individual behaviors can be as follows: R (both cooperate or mutual cooperation), P (both do not cooperate or mutual defection), T (experimental subject does not cooperate when the opponent cooperates), and S (experimental cooperates when the opponent does not cooperate). The cooperative group showed that the permanency in R state was high and, whenever the animal defects (states T and P), it returns to cooperate immediately. Indeed all conditional probabilities to cooperate given a previous outcome were near 1. Besides, the rate of R state was the highest and other states near zero. The probability of R state was significantly different to other states (p = < 1e−8, ANOVA two-way test, n = 8). On the contrary, in the group of non-cooperative animals, any states were significantly different to the other p > 0.05, F = 0.353, ANOVA two-way test, n = 4) and the probability to cooperate given a previous states did not evidence preference for any defined strategy (see Table 1 conditional probability to cooperate). For the group of non-cooperative animals Markov model (see S1 Fig, supplementary materials).

To discard the fact that animals had a preference for one of the levers and, in consequence, their behavior biased independently of the training paradigm, we selected the best four cooperators and applied a reversal procedure immediately after cooperation was reached. All animals learned to cooperate after reversal (cooperation rate, 0.87 ± 0.04, mean ± sem), (see Fig 1F).

We then asked how the ratio in the amount of positive reinforcement of R and T states affects cooperation learning and maintenance. We defined a contrast index CI that measures the relationship between the amount of reward in R and T as follows:Thus, in the experiment shown in Fig 1, the CI was  which is the maximum contrast level constrained to a payoff matrix that favors cooperation, that is, 2PR > PT + PS, assuming that S becomes a negative stimulus induced by timeout. We trained six animals with a payoff matrix (PR = 1, PT = 3, PP = 4, PS = 8) and found that three animals learned to cooperate (0.88 ± 0.01, mean ± sem, see Fig 2A), while others did not (0.64 ± 0.13, mean ± sem, see Fig 2B. The last group was non cooperator, since both their conditional probabilities to cooperate and occupancy R state ratios were near chance. For details see Table 1. Then we changed the amount of reward in order to increase/decrease CI in the cooperative/non-cooperative groups. As it can be seen, a high value of , related to a pay-off matrix (PR = 1, PT = 5, PP = 4, PS = 8), disrupts cooperation in cooperative group, Fig 2A. The cooperation was 0.604 ± 0.102, mean ± sem whereas before 0.88 ± 0.01). When a lower value of  was applied for non cooperator group and the matrix (PR = 2, PT = 3, PP = 4, PS = 8) empowers the cooperation in two out of three animals, cooperation rate 0.711 ± 0.04, mean ± sem, whereas before 0.64 ± 0.13 (see Table 1).

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Fig 2. Effect of changes in the amount of positive reinforcement of R and T.
(A) The rats were pre-trained by pay-off matrix [PR = 1, PT = 3, PP = 4, PS = 8 and contrast ] (filled dots) and the cooperation was strongly affected by change of temptation payoff, decreasing when T payoff increased and matrix with changed to [R = 1, T = 5, P = 4, S = 8 and contrast ] (open circles). There was a significant difference (red circle) in two animals with p < 9.8e−06 (wilcoxon rank-sum test) and the other did not modify her behavior in spite of matrix change. (B) The cooperation enhanced when the matrix changed to [R = 2, T = 3, P = 4, S = 8 and ] (open circles) and the difference was statistically different (p < 0.0062) in two of three subjects, because one had no significant difference after matrix change, p > 0.05(cooperation: 0.7063). (C) The 3D plots related cooperation, reward and timeout. In the group of cooperative animals (filled dots), the change in T (3 pellets to 5 pellets) increased both timeout and reward in order to decrease cooperation (open circles). The comparison between cooperation mean of both groups was significantly different, p < 0.05. (D) In the group of non-cooperative animals (filled dots), they learned to cooperate (open circles) by receiving more reward without significant changes in total timeout. The cooperation was significantly different, p > 0.05. (E,F) The mean of occupancy state rate graph (last five sessions) from cooperative (left) and non-cooperative (right) groups (Mean ± sem). Asterisks denote significant difference, after matrix changed, among T, R, P or S state occupancy and dash line indicates the level of equal rate in each state (that corresponds to a strategy with strongly random component). Before changes (filled dots) and after changes (open circles).

We analyzed how these changes in strategies impact on the amount of received reward and timeout penalties. In the group of cooperative animals, the change in T (3 pellets to 5 pellets) increased both timeout and only a bit reward, as expected when states T, P and S become more probable. The occupancy states ratio before and after matrix change had significant differences among all states, p < 0.05 (wilcoxon ranksum test), (see Fig 2C and 2E). It is worth noting however that the amount of received reward is not the maximum allowed, which would be delivered in the case of an animal that alternates from state T to S indefinitely. On the other hand, when we applied a matrix with a lower contrast  to the group of non-cooperative animals, they enhance significantly their cooperation level, receiving more reward without significant changes in total timeout, (see Fig 2D). In Fig 2F, we show the state occupancy probabilities for this group before and after the change in the payoff matrix. It can be seen that the occupancy state ratio of R had significantly increased after the change in the payoff matrix. It can be observed a significant difference in R and P states, (pR < 0.008 and pP < 0.048, wilcoxon rank-sum test). We showed that when the contrast index increased using a matrix to favor cooperation the animals learned to cooperate, but when the index increased and the matrix favor defection the animals stopped cooperating.

From the results shown in Figs 1 and 2, it is reasonable to ask whether a fine tuning in contrasted reward encourages cooperative behavior. We have shown that eight out of twelve animalas (66%) acquired a cooperative behavior when CI was , while three out of six (50%) succeeded when CI was , as expected when temptation payoff increases. In the same line of reasoning, animals that learned cooperation under  disrupted their cooperative behavior when CI was increased to , while those that had not learned acquired a cooperative behavior when CI was decreased to Fig 3A exemplifies the occupancy and transition probabilities for an animal that disrupted its cooperative behavior when  was changed to . The opposite can be seen in the example of Fig 3B. A non-cooperative animal under a became cooperative when CI was decreased to Fig 3C and 3D show cooperation levels and normalized rewards. A normalized reward was calculated as quotient between the total reward obtained in a session, and the maximum reward achieved using the best strategy. If the opponent subject plays a Tit for tat strategy, the best strategy will depend on the pay-off matrix values. In this way, if the matrix favors cooperation, ALLC will be the best one. In contrast, when the payoff matrix favors no cooperation, alternate between C and D will be the best strategy. It can be seen that both variables follow an inverted U profile as a function of contrast index CI, as expected when a delicate balance between rewards at R and T is mandatory.

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Fig 3. Markov chain diagrams and contrast index.
Markov chain diagrams are shown (the size of circle means of occupancy state rate and the arrow’s width are proportional to the probability of cooperate given (A) occupancy state and transition probabilities for an animal that disrupted its cooperative behavior when contrast index  was changed to  and pay-off matrix was changed [PTPRPPPS] = [3p, 1p, 4s, 8s] to [5p, 1p, 4s, 8s] (p = pellet and s = seconds). The thickness of blue arrows (conditional probabilities of cooperation) become thinner after change (for values see Table 1). (B) The opposite situation can be seen, non-cooperative animal becomes more cooperative when  was decreased to in a matrix that favors cooperation. The blue arrows become thicker after change (for values see Table 1). (CD) shows cooperation and timeout levels as a function of CI. Here, it can be seen that both variables follow an inverted U profile in correlation with the contrast index increase and if the payoff matrix favors or not the cooperation behavior.

Discussion and conclusion


In this work, we study the contrasted role between reinforcements in the learning of reciprocal altruism learning in rats. Traditionally, reciprocal altruism is achieved by playing the iterated prisoner’s dilemma game (iPD) when an experimental subject is confronted to a reciprocal opponent. The payoff matrix used has positive and negative reinforcements with high contrasted between positive and negative pairs and also uses discriminating amount of reinforcements [2526]. In our experiment, pellets were used as positive reinforcements, and timeout as negative reinforcement. In this way, the positive and negative reinforcements acted as strengtheners of mutual cooperation behavior likelihood [28]. Our results show for the first time high levels of cooperation (86,11%) and mutual cooperation (76,32%) in iPD, (see Fig 1B). Previous published works have taught reciprocity using iPD game, showing that animals prefer short-term benefits or only improve a poor level of cooperation [49202930]. In other works, authors employed a special treatment to enhance cooperation preference [10233132]. A possible explanation is that using standard matrices (for example: PT = 6, PR = 4, PP = 1, PS = 0), animals were not able to discriminate between the amount of reinforcement obtained in the long-term in comparison to short-term [24]. For example, if a rat played four sessions [C C C C] he would get 16 pellets, and if played [C D D D] he would get 12 pellets. In our experiment, rats using the same choices earn 4 pellets and no timeout in the first case, and 3 pellets plus a 16 seconds timeout in the second case.

A dynamic system can be represented with Markov diagrams and its associated state transition vector. In this case, each state (T, R, P, S, see Results section) will have two associated conditional probabilities: to cooperate or not to cooperate given state. In an IPD game with an opponent using a Tit for tat strategy, a rational player should maximize the positive reinforcement and cancel the negative reinforcement. In this way, while the opponent performed a reciprocal behavior, the player follows an ALLC strategy with conditional cooperation probability near 1, independent of previous states (T, R, P o S). In a pay-off matrix with addable value (as for an example (PT = 6, PR = 4, PP = 1, PS = 0), it is possible to calculate the cooperative strategy through mathematical analysis [3334], but in our experiment positive and negative reinforcers have different units (pellets and time respectively). Due to this reason, we did a single analysis using the Markov chain diagram. In the first experiment, we found that animals adopted two well defined strategies. On one hand, a group of 8 animals proved to have learned a cooperative strategy while other 4 animals responded at random (see S1B Fig, Supporting information). The strategy of the first group, (see Fig 1E), show that conditional probabilities to cooperation given previous state T, R, P or S were near 1 (0.760, 0.845, 0.929 and 0.870, respectively) and in this fashion after defected they immediately return to the mutual cooperation state, R. In various works, results were presented with Markov diagrams and its associated transition vector [10112332] and showed that conditional probabilities of cooperation were not high when facing a reciprocal opponent. In this protocol, with the matrix (PT = 2, PR = 1, PP = 4sPS = 8s), there are two theoretical strategies that maximize appetite reinforcement: one is ALLC strategy and the other an alternating between cooperation (C) and defection (D) strategy. The latter, also maximizes positive reinforcement when alternating between cooperation and defection options, but it also increases negative reinforcement (timeout). In this case, ALLC strategy is the only one that maximizes positive reinforcement and minimizes the negative one (Pareto Optimum). Since negative reinforcement is timeout, ALLC strategy gives more food per unit of time. In this case, the role of the negative reinforcement appears.

In order to evaluate if animals developed ALLC strategy by place preference (after animals learned iPD) or by reward maximization, they were trained on reversal, (see Fig 1F), and we observed that animals relearn reciprocal altruism when they are exposed to a new lever’s contingency.

Finally, after animals adopted a strategy, we evaluated if a change in the payoff matrix could modify their behavior. Therefore, we studied the effect of modifying positive reinforcements (see Fig 2A and 2B). Animals were pre-trained with a payoff matrix where alternating between C and D strategy gives more positive reinforcements than with an ALLC strategy, keeping the same negative reinforcement as in the first experiment. We observed that only half of the animals learned to cooperate although all of them obtained the same mean amount reward (pellet) (see Fig 2C and 2D). The cooperative group was trained with a matrix where the pay-off T was increased (Fig 2A), then we observed that cooperative behavior decreased. Animals reduced frequency of R state and increased frequency of P state, proving that they preferred a small-immediate option instead of a large-delayed option. This behavior is similar to the one observed in birds ([30]). In the second group, we applied a matrix that keeps the proportions of reinforcements in T and R similar to the most common matrix (PT = 3pPR = 2p equal proportion to PT = 6pPR = 4). It was observed that animals modified their behavior and became more cooperative (Fig 2B). These results show that rats that learned to cooperate with an appropriate matrix stop cooperating when a temptation payoff (T) is sufficiently increased (matrix with high contrast index). However, if non-cooperative animals are trained with a matrix that favors cooperation (matrix with low contrast index), they become cooperators. In the latter case, the achieved cooperation level was comparable to results shared in diverse bibliography. We observe that if an iPD matrix uses large positive reward, it improves less cooperation than one with small rewards, shown that satisfying the relationship among iPD reinforcement was not enough to achieve high mutual cooperation behavior. The reciprocal altruist behavior in humans, monkeys and elephants has been studied in laboratories showing high levels of cooperation [13153537], however in rats and birds those levels of cooperation were much lower. Our results show that by using positive and negative reinforcements and an appropriate contrast between rewards, rats have cognitive capacity to learn reciprocal altruism. This finding allows to deduce learning of reciprocal altruism appeared early in evolution.

Supporting information in the original article





Acknowledgments


Supported by PICT 2012-1519 and PICT-2016-2145. We wish to thank Lic. Melanie Marino.

References in the original article