Female fruit flies copy the acceptance, but not the rejection, of a mate

Female fruit flies copy the acceptance, but not the rejection, of a mate. Sabine Nöbel, Magdalena Monier, Laura Fargeot, Guillaume Lespagnol, Etienne Danchin, Guillaume Isabel. Behavioral Ecology, arac071, Aug 8 2022, https://doi.org/10.1093/beheco/arac071

Abstract: Acceptance and avoidance can be socially transmitted, especially in the case of mate choice. When a Drosophila melanogaster female observes a conspecific female (called demonstrator female) choosing to mate with one of two males, the former female (called observer female) can memorize and copy the latter female’s choice. Traditionally in mate-copying experiments, demonstrations provide two types of information to observer females, namely, the acceptance (positive) of one male and the rejection of the other male (negative). To disentangle the respective roles of positive and negative information in Drosophila mate copying, we performed experiments in which demonstrations provided only one type of information at a time. We found that positive information alone is sufficient to trigger mate copying. Observer females preferred males of phenotype A after watching a female mating with a male of phenotype A in the absence of any other male. Contrastingly, negative information alone (provided by a demonstrator female actively rejecting a male of phenotype B) did not affect future observer females’ mate choice. These results suggest that the informative part of demonstrations in Drosophila mate-copying experiments lies mainly, if not exclusively, in the positive information provided by the copulation with a given male. We discuss the reasons for such a result and suggest that Drosophila females learn to prefer the successful males, implying that the underlying learning mechanisms may be shared with those of appetitive memory in non-social associative learning.

DISCUSSION

Our goal was to disentangle the role of positive and negative information during the observation of binary mate-choice decisions in D. melanogaster in order to evaluate its ecological relevance. We found that females, that received positive information only or positive and negative information at the same time, learned and copied the choice of the demonstrator females, as in previous studies (Dagaeff et al. 2016; Danchin et al. 2018; Nöbel et al. 2018; Monier et al. 2019). We further found no significant difference in the learning capacities of females of these two treatments. In contrast, females receiving only negative information did not significantly avoid the color they saw being rejected, which differs from a previous study in fish (Witte and Ueding 2003). Thus, positive information appears sufficient to elicit mate copying after one demonstration in fruit flies.

The absence of mate copying in the rejection treatment suggests that one demonstration containing rejection(s) of a male is not sufficient to elicit avoidance behavior in the observer females. This may be because a female can reject a male for reasons that are independent from its quality, like the female being non-receptive (Connolly and Cook 1973; Neckameyer 1998), as this is the case in our study. Alternatively, it may be that observer females were less interested in negative demonstrations as they did not involve copulation, in which case the negative result would simply result from a lack of interest in the demonstrations. Or it could be that the solitary male and the rejected male were evaluated in the same way, and thus, no preference was developed.

A recent study of aversive olfactory memory in Drosophila showed that an initially neutral stimulus can become attractive to fruit flies under some circumstances—the “safety memory” (Jacob and Waddell 2020). Briefly, after a multiple spaced training with sequences of conditioned stimuli (CS) simultaneously with an aversive cue (CS+) followed by another CS without reinforcement (CS−), Jacob and Waddell conclude that the individuals display both a CS + avoidance and an approach movement towards the CS- when later given the choice between the CS + and CS− odors. Thus, in our design, a sequence of several rejections (showing first a male of phenotype A rejected by a female and then a single male of another phenotype B, repeated several times) might elicit aversive learning for phenotype A leading to a choice for the male phenotype B. Interestingly, in the fruit fly larva, appetitive but not aversive olfactory stimuli support associative gustatory learning (Hendel et al. 2005). Opposite to what we observe in fruit fly females, female sailfin mollies (Poecillia latipinna) copy the rejection of a male (Witte and Ueding 2003). However, the setup used in that study was quite different from ours, as the rejection demonstration consisted of a sequence of four 12-min video of four different females escaping from a courting male, so that the rejection cue seemed much stronger than in the present study that only involved a single demonstrator female. Similarly, in humans, women, but not men, decrease their interest for a relationship to a demonstrator after watching a speed-dating video in which the demonstrator and a potential partner showed mutual lack of interest (Place et al. 2010). This can indicate that beyond the effect of the experimental conditions, different species use different social cues for mate copying. However, the motivations to reject a partner are way less studied than for building specific mating preferences.

A last alternative can be that in nature newly emerged females do not see older females choosing between only two males, but rather see females choosing among many males to copulate with one of them. The fact that the former chooses that specific male is informative in itself but the fact that she rejected all other potential male does not reveal much information about all the non-selected males. This purely statistical fact may explain the absence of an effect of seeing only a rejection.

Finally, our results suggest that in the classical Drosophila mate-copying design, the rejected male shown in the demonstration may not constitute the prominent cue triggering learning in the observer female. Moreover, the presentation of a male of the opposite color together with the copulating pair in the classical demonstration might even constitute a distractive stimulus, as indirectly suggested by Germain et al. (2016 experiment 3). In nature, females may observe copulations longer than rejection as copulations likely last for more than 30 min (Markow 2000), while rejections are brief and thus far less prominent (Gromko and Markow 1993). It is thus possible that our result is explained by the fact that D. melanogaster females evolved an ability to gather social information from the most easily detectable and reliable social cues. Alternatively, females might pay attention to rejection events too but might have difficulties in interpreting them or distinguishing them from other neutral information, such as solitary males.

Our finding that the acceptance of a male by the demonstrator female is the most relevant cue to elicit full mate copying by the observer female suggests that it involves networks of appetitive learning neurons and mechanisms rather than the aversive pathway. Several authors suggested that social learning in many contexts can have an associative explanation (e.g., Munger et al. 2010 ; Avarguès-Weber et al. 2015; Heyes and Pearce 2015; Leadbeater and Dawson 2017). For mate copying, this has yet to be proven. At the moment, asocial learning, like olfactory associative direct learning, is way better understood. Here the pairing between a conditioned stimulus (CS; for instance, odor A) and an appetitive US (sucrose) leads flies to prefer odor A over B even in the absence of any reward (Tempel et al. 1983) through the association of odor A to the reward (Schultz et al. 1997). In our social learning paradigm, we can speculate that the relevant cues eliciting learning are the color of the copulating males in association with the successful mating. Hence, the copulating pair would mediate the appetitive US, while male color would constitute the CS (Avarguès-Weber et al. 2015). Under this hypothesis, it would be interesting to study whether mate-copying mechanisms resemble those of visual, appetitive, associative learning, given that its neural bases are now well-understood (Vogt et al. 2014, 2016).

More generally, understanding how social learning works can only help sharpening our view on the evolution of the different types of learning, opening the way to new theories about the evolution of behavior, cognition, and culture in invertebrates.

The population is widely exposed to online false news; however, echo chambers are minimal, and the most avid readers of false news content regularly expose themselves to mainstream news sources

Zhang, Jiding and Moon, Ken and Veeraraghavan, Senthil K., Does Fake News Create Echo Chambers? (June 23, 2022). SSRN: http://dx.doi.org/10.2139/ssrn.4144897

Abstract: Platforms have come under criticism from regulatory agencies, policymakers, and media scholars for the unfettered spread of fake news online. A key concern is that, as fake news becomes prevalent, individuals may fall into online "echo chambers" that predominantly expose them only to fake news. Using a dataset reporting 30,995 individual households’ online activity, we empirically examine the reach of false news content and whether echo chambers exist. We find that the population is widely exposed to online false news. However, echo chambers are minimal, and the most avid readers of false news content regularly expose themselves to mainstream news sources. Using a natural experiment occurring on a major social media platform, we find that being exposed to false news content causes households to increase their exposure to countervailing mainstream news (by 9.1% in the experiment). Hence, a naive intervention that reduces the supply of false news sources on a platform also reduces the overall consumption of news. Based on a structural model of household decisions whether to diversify their online news sources, we prescribe how platforms should moderate false news content. We find that platforms can further reduce the size of echo chambers (by 12-18%) by focusing their content moderation efforts on the households that are most susceptible to consuming predominantly false news, instead of the households most deeply exposed to false news.

Keywords: Digital operations, Echo chambers, Marketplace for news, Natural experiment, Platforms, Structural estimation

Check also other literature with references: Politically partisan left-right online news echo chambers are real, but only a minority of approximately 5% of internet news users inhabit them; the continued popularity of mainstream outlets often preclude the formation of large partisan echo chambers

Nearshoring in Mexico: In 2018-2021 the proportion of manufactured goods imported into the US from Mexico barely changed; Asian countries but China increased their share of US manufactured goods imports from 12.6 pct to 17.4 pct

Why Mexico is missing its chance to profit from US-China decoupling. Michael Stott and Christine Murray. Financial Times Jul 3 2022. https://www.ft.com/content/7fc2adf0-0577-4e13-b9a3-218dda2ddd5b

A predicted economic boom from American companies relocating closer to home has not arrived. Many blame the president

Michael Stott and Christine Murray in Mexico City. July  3 2022

When Donald Trump started a trade war with China in 2018, Mexico looked well placed to benefit.

For American manufacturers scrambling to dodge newly imposed tariffs on Chinese imports, the attraction of moving production to their southern neighbour seemed clear. Mexico offered a skilled workforce, good road and rail connections, an established export industry and privileged trade access.

The stage appeared to be set for a boom in “nearshoring” — relocating production closer to home. A bonanza beckoned, perhaps rivalling the one Mexico enjoyed in 1994 after the signing of the North American Free Trade Agreement.

It didn’t happen. Between 2018 and 2021 the proportion of manufactured goods imported into the US from Mexico barely changed according to data compiled by Kearney, the consultancy. Instead the rewards of the China boycott were reaped by low-cost Asian competitors including Vietnam and Taiwan. Asian countries other than China increased their share of US manufactured goods imports from 12.6 per cent to 17.4 per cent over the period.

The rapid growth in total US goods imports from Mexico that might have been expected had nearshoring taken off was also missing. It rose by just 11.8 per cent over three years to $384.6bn in 2021, according to the US Census Bureau — after allowing for inflation the total increase was just under 4 per cent.

“Most of the gains have gone to Asean, India and Korea,” said UBS in a recent report examining nearshoring in Mexico. “At least for now, the US import penetration data does not support the view that Mexico has been a net beneficiary of nearshoring.”

There have been some signs of increased activity. Mexico attracted $34.9bn in foreign direct investment in the year to the end of March, up from $26.1bn a year earlier — although that figure includes large one-off transactions outside the manufacturing sector. Industrial parks in the north of the country are full and some international companies have relocated there. But despite this, Mexico’s overall economic growth over the past three years has been among the weakest of Latin America’s larger economies.

“This should be the golden era for investment in Mexico,” says Mauricio Claver-Carone, president of the Inter-American Development Bank and a big supporter of nearshoring. Calculations by the IDB suggest Mexico has the potential to deliver almost half of the $78bn in additional annual exports from nearshoring that the bank estimates Latin America could generate in the medium term.

Claver-Carone says there is plenty of interest from executives in moving to Mexico: “Not a day goes by without a major company calling me up and saying, ‘Hey, we want to invest [in moving production], can you help us in Mexico?’”

Yet the interest has not yet translated into measurable economic gains, says Ernesto Revilla, head of Latin America economics at Citi and a former Mexican finance ministry official. While nearshoring has become a buzzword in discussions about the future of the Mexican economy, he says, “nobody knows how to continue the conversation”.

The ‘moral economy’

Much of the blame for Mexico’s lacklustre economic performance has fallen on the shoulders of President Andrés Manuel López Obrador. Business leaders, diplomats and investors say he has been hostile to some foreign companies and complain that his capricious decision-making and authoritarian tendencies are scaring off investment.

López Obrador came to power in 2018 on a leftist, nationalist platform. He dreams of restoring Mexico’s economy to the oil-powered, state-dominated days of the 1970s. His quixotic pledge of a “fourth transformation” of the country — a change he puts on a par with Mexico gaining independence from Spain — promises to eliminate corruption and speed up growth. He wants to create a “moral economy” that puts the poor first, but his regular naming and shaming of multinationals at daily news conferences does little to instil confidence in foreign businesses contemplating forays into Mexico.

Despite his heavy criticism of low growth under previous “neoliberal” governments, in the first three full years of his own administration Mexico’s gross domestic product contracted overall. It is the only major Latin American economy whose output will still be below pre-pandemic levels by the end of this year, according to estimates from JPMorgan.

Mexico’s poor performance is “a direct consequence of . . . Amlo-nomics, which is extremely tight macroeconomic policy coupled with very bad microeconomics,” says Citi’s Revilla, using the acronym that has become the president’s nickname. “The result is not surprising: it’s very low growth.”

Andrés Rozental, a former deputy foreign minister who now works as a consultant, agrees. “We had everything to gain from the global geopolitical situation,” he says. “But it’s all been squandered because of López Obrador’s anti-private sector policies.”

The president’s obsession with “republican austerity” — he flies economy class and took a large personal pay cut — has meant salary reductions for top officials. This in turn has led to a brain drain, budget cuts at government agencies and sharply reduced spending on infrastructure.

Mexico has the lowest public investment among OECD countries, spending just 1.3 per cent of GDP in 2019, the first year of López Obrador’s government. Much of what remains is channelled into a handful of grandiose projects championed by the president. The most prominent is a new oil refinery in his home state of Tabasco, whose cost has spiralled to between $16bn and $18bn, according to Bloomberg.

López Obrador has repeatedly attacked Mexico’s autonomous regulatory agencies, criticising their decisions, cutting budgets and suggesting that they collude corruptly with business.

“Mexico has a big comparative advantage in farming but there are problems in [agricultural health agency] Senasica,” says Luis de la Calle, an economist who runs a consulting firm in Mexico City. “We are a big exporter of fish and seafood, but the government took away funding from [fishing council] Conapesca. We are a big exporter of medical equipment but they cut money for the certifying body Cofepris. It’s madness.”

[Photo w/text: López Obrador dreams of restoring Mexico’s economy to the oil-powered, state-dominated days of the 1970s]

One of López Obrador’s first decisions as president was to shut the government agency ProMéxico, which worked to promote investment in Mexico and had 51 offices overseas. The president said they were “supposedly dedicated to promoting the country, which is ridiculous because there are no ProGermany, ProFrance or ProCanada offices”. In fact, most countries have government agencies to promote foreign investment.

“Deep down,” de la Calle says, “López Obrador believes that economic success is not possible by itself. It is always the result of luck or corruption.”

Foreign targets

Despite the downbeat mood, the government and some experts insist Mexico could still take advantage of supply chain disruptions caused by Covid-19, higher shipping costs and Ukraine invasion-related fuel price surges that make the economics of moving production to Mexico more compelling.

Tatiana Clouthier, Mexico’s economy minister, argues the country is “doing well for investment” in nearshoring. “It always could be [more] . . . There always could be better circumstances for everything,” she says.

For many years, Clouthier says, Mexico has suffered from “an imbalance, where the thinking was about how to strengthen investment and the social part was ignored”. Now, she says, “the idea is to try to compensate for that”. In practice, the shift in policy has brought decisions that upset foreign companies. Those from the US, Mexico’s biggest foreign investor, have been particularly exposed.

Last month the government forced Vulcan Materials, the biggest American producer of aggregates used in US construction, to halt quarrying in the southeastern state of Quintana Roo, with López Obrador warning that an “ecological catastrophe” was taking place. Vulcan, which has operated in the area for 30 years, has described the shutdown as “arbitrary and illegal” and has sought arbitration under the US-Mexico-Canada Agreement, the successor trade pact to Nafta.

The dispute prompted a letter from a group of US senators last month to President Joe Biden, calling on him to take immediate action to stop Mexico’s “aggression towards US companies”. “If these violations are allowed to continue, they will . . . encourage businesses to seek more predictable and suitable markets elsewhere,” the letter said.

Economy minister Tatiana Clouthier argues the country is ‘doing well for investment’ in nearshoring © Lujan Agusti/Bloomberg

In 2020, Constellation Brands, a large American drinks company that makes Corona beer for the US market, cancelled a $1.4bn factory being built in the northern city of Mexicali after the government revoked its construction permit. The company has since agreed to build a facility in Veracruz but work has yet to start.

Companies from Spain, the former colonial power, have also been targeted. That Spain is Mexico’s second biggest foreign investor after the US cuts little ice. Spanish companies “abused our country and our peoples”, López Obrador told a news conference in February. In a reference to the post-Nafta decades, he added: “During the neoliberal period, Spanish companies supported by the political establishment saw us as a land to be conquered.”

A particular target of the president’s ire has been Iberdrola, the Spanish power company that owns a string of electricity generating plants in Mexico. He has accused it of corrupt deals, something Iberdrola denies. Iberdrola had announced plans to invest $5bn in renewable energy projects in Mexico during López Obrador’s term but has now abandoned almost all of its Mexican investment and is fighting the government in the courts.

The attacks on Iberdrola are part of López Obrador’s crusade to restore the state to pride of place in Mexico’s energy sector. Previous governments had chipped away at the state’s historic monopoly over energy, allowing the private sector to operate electricity generating plants serving industrial customers in the wake of Nafta.

A landmark 2013 constitutional reform opened up the oil, gas and electricity sectors more widely but, since he took power, López Obrador has opposed these reforms and launched a wave of initiatives to roll them back. These include a law changing Mexico’s electricity grid rules to favour the fossil fuel-heavy state power generator, CFE, at the expense of private companies.

As foreign power generators fight the government in the courts, companies that need power for new plants in Mexico are struggling to secure adequate supplies. Worse, the CFE’s reliance on CO₂-emitting oil and gas plants rules it out for multinationals which are committed to reaching net zero carbon emissions targets.

Alberto de la Fuente, president of Mexico’s Executive Council of Global Companies, which represents 57 multinationals accounting for 40 per cent of foreign direct investment, has warned that if Mexico cannot fulfil its clean energy goals, companies “will simply leave”.

Behind closed doors

While foreign companies have borne the brunt of López Obrador’s attacks, the handful of big Mexican businesses that control large parts of the economy have been less affected.

When the president wanted to tackle inflation, his government invited Mexican business leaders for private conversations to agree an informal pact limiting price rises on basic groceries. “It wasn’t a big sacrifice,” noted the owner of one large Mexican group.

Mexico’s oligarchs have reinforced the impression of a cosy relationship with the president by making supportive statements in public and confining any criticism to conversations behind closed doors. “All the Mexican business leaders complain about Amlo,” says the chief executive of one big foreign company. “But when they meet him, they all appear afterwards in public saying how wonderful he is . . It’s a circle of collusion.”

López Obrador has also made life difficult for international businesses in Mexico in less direct ways. Shortly after taking office, he cancelled a $13bn new airport for Mexico City that would have replaced the congested Benito Juárez facility, claiming the partly-executed project was too extravagant, even though cancelling it cost billions.

“The airport decision was 100 per cent political,” says one leading Mexican businessman. “It was the worst economic decision this government has made.”

Instead, López Obrador ordered the army to remodel a nearby military air base and turn it into an additional airport for the capital. The new Felipe Ángeles facility opened in March at a cost estimated by former finance minister Carlos Urzúa of $5.7bn. Most airlines have shunned it because of its poor road and rail connections (the government is working on new transport links). Its only regular international flight goes to Venezuela, a nation under US sanctions. Flights to Cuba, another nation under US sanctions, are due to start in July.

The new airport is only 45km from Benito Juárez, a proximity that has forced a controversial redesign of Mexico City’s airspace. This triggered what the International Air Transport Association called a “very worrying” increase in alerts over flights at risk of collision. Mexico’s airlines are currently unable to expand flights to the US because the Federal Aviation Administration downgraded its air safety rating last year.

“We are losing out on the potential we have as a country and as a city” because of the airport situation, says the chief executive of the foreign firm. “There may come a moment where you have to fly to Monterrey to take a plane to Barcelona.”

Despite this, Omar Troncoso, a nearshoring expert at Kearney in Mexico, sees some reason for optimism in the recent geopolitical shifts. He said that as recently as last year, “Mexico was still more expensive than many [Asian] low-cost countries” when total costs of getting the product to the customer were factored in. Then “we had a massive disruption in [the] supply chain and . . . the price of a container being brought from China to the US skyrocketed . . . It [is] now cheaper to produce in Mexico,” he says.

Troncoso believes that the nearshoring aimed at supplying the US market currently under way will take another two or three years to show up in the data. “If you . . . look for a space in some of the border cities . . . the real estate agents will tell you that you’re going to have to wait until 2025 — everything . . . is already sold out.”

Sergio Argüelles González, head of Mexico’s industrial parks association, says 2021 was a bumper year with “spectacular demand” and predicts this will continue if there are sufficient power supplies.

“In spite of Amlo, something is happening,” says Citi’s Revilla. “The [momentum] for nearshoring is big and hopefully will outlast Amlo and help Mexico in the medium term.” De la Calle, the consultant, voices a similar view: “Nearshoring is happening,” he says. “But . . . if we did things properly, it could be three times more than it is now . . . The opportunity cost of López Obrador is very big.” 

Parishes affected by the Dissolution of the English monasteries, 1535, experienced a rise of the gentry & had more innovation, higher yield in agriculture, more population working outside of agriculture, & ultimately higher levels of industrialization

The Long-Run Impact of the Dissolution of the English Monasteries. Leander Heldring, James A Robinson, Sebastian Vollmer. The Quarterly Journal of Economics, Volume 136, Issue 4, November 2021, Pages 2093–2145, https://doi.org/10.1093/qje/qjab030

Abstract: We use the effect of the Dissolution of the English Monasteries after 1535 to test the commercialization hypothesis about the roots of long-run English economic development. Before the Dissolution, monastic lands were relatively unencumbered by inefficient feudal land tenure but could not be sold. The Dissolution created a market for formerly monastic lands, which could now be more effectively commercialized relative to nonmonastic lands, where feudal tenure persisted until the twentieth century. We show that parishes affected by the Dissolution subsequently experienced a rise of the gentry and had more innovation and higher yield in agriculture, a greater share of the population working outside of agriculture, and ultimately higher levels of industrialization. Our results are consistent with explanations of the Agricultural and Industrial Revolutions which emphasize the commercialization of society as a key precondition for taking advantage of technological change and new economic opportunities.

JEL N43 - Europe: Pre-1913N63 - Europe: Pre-1913N93 - Europe: Pre-1913O14 - Industrialization; Manufacturing and Service Industries; Choice of TechnologyQ15 - Land Ownership and Tenure; Land Reform; Land Use; Irrigation; Agriculture and Environment

6 Conclusions

In this paper we conducted what to our knowledge is the first empirical investigation of one aspect of the salient commercialization thesis about the causes of industrialization and the industrial revolution in England. Though we cannot test the idea that it was commercialization that caused the industrial revolution, we used the impact of the Dissolution of the monasteries in England between 1536 and 1540 as a source of variation in the extent of commercialization within England. Tawney (1941a,b) first proposed that the Dissolution and subsequent sell off of church land, representing around 1/3 of agricultural land in England, created a huge shock to the land market with profound consequences. We argue that this can be viewed as a natural experiment in the modernization of economic institutions and we hypothesized that the subsequent thickening of the land market would have had a major positive impact on resource allocation and incentives. This was particularly because monastic lands were relatively free of customary perpetual copyhold tenancies which were a direct legacy of feudalism. To investigate this we digitized the 1535 Valor Ecclesiasticus, the census that Henry VIII commissioned on monastic incomes.

Using the presence of monastically owned land at the parish level as our main explanatory variable we showed that the Dissolution had significant positive effects on industrialization which we measured using data from the 1838 Mill Census, the first time the British government collected systematic data on this driving sector of the Industrial Revolution.

We also showed the Dissolution was associated with structural change, specifically the movement of labor out of agriculture and into more industrialized sectors of the economy.

We then examined several channels which might link the Dissolution to these longrun outcomes. We showed that the Dissolution was associated, as Tawney hypothesized, with social change and the rise of a new class of commercially minded farmer. It was also associated with faster conversion from Catholicism, another factor plausibly linked to better economic performance.

We further found the Dissolution to be associated with greater agricultural investment, measured by parenting and land enclosures, and higher wheat yields. All in all, our findings support a quite traditional theory of the industrial, and perhaps the agricultural, revolution; that it was at least partially caused by the increasing commercialization of the economy which had a series of institutional, social and economics effect.

Probability of males to outlive females: an international comparison from 1751 to 2020

Probability of males to outlive females: an international comparison from 1751 to 2020. Marie-Pier Bergeron-Boucher et al. BMJ Open, Volume 12, Issue 8, Aug 2022. https://bmjopen.bmj.com/content/12/8/e059964

Abstract

Objective To measure sex differences in lifespan based on the probability of males to outlive females.

Design International comparison of national and regional sex-specific life tables from the Human Mortality Database and the World Population Prospects.

Setting 199 populations spanning all continents, between 1751 and 2020.

Primary outcome measure We used the outsurvival statistic ( φ ) to measure inequality in lifespan between sexes, which is interpreted here as the probability of males to outlive females.

Results In random pairs of one male and one female at age 0, the probability of the male outliving the female varies between 25% and 50% for life tables in almost all years since 1751 and across almost all populations. We show that φ is negatively correlated with sex differences in life expectancy and positively correlated with the level of lifespan variation. The important reduction of lifespan inequality observed in recent years has made it less likely for a male to outlive a female.

Conclusions Although male life expectancy is generally lower than female life expectancy, and male death rates are usually higher at all ages, males have a substantial chance of outliving females. These findings challenge the general impression that ‘men do not live as long as women’ and reveal a more nuanced inequality in lifespans between females and males.

Discussion

Our study reveals a nuanced inequality in lifespan between females and males, with between one and two men out of four outliving a randomly paired woman in almost all points in time across 199 populations. These results complement the picture given by the comparisons based on life expectancy, which is a summary measure with no information on variation. A blind interpretation of life expectancy differences can sometimes lead to a distorted perception of the actual inequalities. Not all females outlive males, even if a majority do. But the minority that do not is not small. For example, a sex difference in life expectancy at birth of 10 years can be associated with a probability of males outliving females as high as 40%, indicating that 40% of males have a longer lifespan than that of a randomly paired female. Not all males have a disadvantage of 10 years, which is overlooked by solely making comparisons of life expectancy. However, a small number of males will live very short lives to result in that difference. For example, more baby boys die than baby girls in most countries.

The length of the lifespan of an individual results from a complex combination of biological, environmental and behavioural factors. Being male or female does impact lifespan, but it is not the only determinant contributing to inequalities. Lifespan has been shown to be influenced by marital status, income, education, race/ethnicity, urban/rural residence, etc.33 As we only disaggregated the population by sex and because of this complex interaction, lifespan distributions of females and males overlap. This nuance is captured by the φ metric. Males with a lower education level or who are unmarried have a particularly low chance of outliving a female. But males with a university degree or who are married have a higher chance of outliving females, in particular females with a lower education level and who are single.

As previously discussed, the φ metric expresses the probability of males to outlive females among randomly paired individuals, assuming independence between populations. However, males and females in a population are generally not random pairs but often couples, whose health and mortality have been found to be positively correlated due to a strong effect of social ties on health and longevity.34 Coupled individuals also influence each other’s health,35 and this is particularly true for males, who benefit more than females from being in a stable relationship.36 The datasets used for the analysis do not permit the estimation of the probability of males outliving females for non-randomly paired individuals. However, the outsurvival statistic relates to the probability of the husbands to outlive their wives, and even though such a measure accounts for the difference in age between husband and wife, it has been shown generally to be between 30% and 40%,37–39 values that are quite close to φ .

Other measures of overlap and distance between distributions could have been used. In the online supplemental materials, we compare the outsurvival statistic with a stratification index used by Shi and colleagues20 and the KL divergence. We found that all three indicators are strongly correlated and using any one of these would not have changed the general conclusions from this article. However, unlike the other indicators, φ directly indicates when males live longer than females, which we found in a few instances.

Trends over time in φ are consistent with the reversed trends in sex differences in life expectancy40: in developed countries, the probability of males outliving females decreased until the 1970s, after which it gradually increased in all populations. Studies showed that the increase in sex differences in mortality emerged in cohorts born after 1880,10 41 which is consistent with our analysis of φ (see online supplemental materials). The increase and decrease in sex differences in life expectancy were mainly attributed to the smoking epidemic and other behavioural differences between sexes.7 13 42

The φ values are generally higher in low/middle-income countries. However, this should not be interpreted as a sign of greater gender equality in survival. Southern Asian countries had very high φ values, above 50% in the 1950s and 1960s. Studies for India showed that mortality below age 5 was higher for females than males and remained higher for females in recent years.43 44 However, females had a growing mortality advantage above age 15 years since the 1980s, ‘balancing out’ the disadvantage at younger ages. The reasons for the higher φ and decreasing trends in developing regions vary across countries. It is outside the scope of this study to provide a detailed explanation for the trends in each country.

The outsurvival statistic can be informative for public health interventions.21 Governments develop public health programmes to reduce lifespan inequalities at different levels (eg, socioeconomic status, race, sex, etc). It would be misleading to say that half of the population is disadvantaged by sex differences in lifespan. The inequalities are more nuanced. If 40% of males live longer than females, it could be argued that if a policy aiming at reducing inequalities between sexes targeted the full male population, some of the efforts and investments would be misallocated. Such a policy could be more efficient if φ approaches 0, indicating that sex would explain a large part of the lifespan inequalities within the population, whereas a φ closer to 0.5 indicates that other characteristics (eg, socioeconomic and marital statuses) are involved in creating inequalities. We showed that some subpopulations of males have a high probability (above 50%) of outliving some subpopulations of females. Males who are married or have a university degree tend to outlive females who are unmarried or do not have a high school diploma. Inequalities in lifespan between sexes are attributable to some individuals within each population and not to the whole population. Indeed, Luy and Gast12 found that male excess mortality is mainly caused by some specific subpopulations of males with particularly high mortality. Being able to better identify the characteristics of the short-lived men could more efficiently help tackle male–female inequality.

An important result of our analysis is that the smaller the SD in the age at death, the smaller the φ . The reduction of lifespan inequality observed over time has then made it less likely for males to outlive females. This is partly explained by the fact that lifespan variation reduction has been driven by mortality declines at younger ages.45 When looking at the lifespan distribution (as in figure 1, scenario D), survival improvements at younger ages narrowed the left tails of the distribution for both sexes. By reducing the left tail of female distribution, without increasing the right tail of the male distribution, the overlapping area is reduced. In other words, the number of females with shorter lifespan, easier to outlive, decreased over time. Indeed, it has been shown that mortality declined at a faster pace for females than males below age 50, especially in the first half of the 20th century.46 47 This finding implies that more efforts are required today than in the past to reduce these inequalities, for a same difference in life expectancy. While inequalities were mainly attributable to infant and child mortality, they are today increasingly attributable to older and broader age groups. Men maintained their disadvantage at younger ages, but also faced an increasing disadvantage at older ages. Men are more prone to accidents and homicides in their 20s and 30s than females, and they tend to smoke and drink more leading to higher cancer prevalence and death in their 60s. At the same time, women benefited from reduced maternal mortality and recorded faster mortality decline at older ages. Efforts in reducing lifespan inequalities must thus target diverse factors, causes and ages.13 46 48

A decrease of φ might indicate a discrepancy in the causes of death that affect males and females. External mortality due to accidents and suicide has become more relevant in shaping sex differences in survival in recent years in high-income populations.12 Another example is observed in Latin American populations, where homicides and violent deaths have had an increased burden among males in comparison with females since the 1990s.49 50 In Mexico, for example, the increase in homicide mortality, especially among men between 20 and 40 years, contributed to increasing the gap in mortality between females and males.51 This phenomenon is reflected in the decrease over time in the overlapping of lifespan distributions, directly informing healthcare systems of emerging inequalities.

However, one might ask if a wider overlapping is necessarily better for healthcare systems. On the one hand, a larger overlapping means less inequality between sexes, but on its own it does not ensure that there is more ‘health justice’. For example, if the overlapping areas are large, this still shows a situation of great uncertainty in lifespan for both groups. One health evaluator actor could even prefer a situation where there is a small gap between groups but less inequality within the groups. In the case of sex differences, there might always be between-group differences due to biological factors,2 52 but more health equity could be reached by reducing within-group inequalities. We argue that the outsurvival statistic is a new tool to evaluate health inequalities between groups within a population by uncovering underlying dynamics that are otherwise hidden when looking only at conventional indicators. Therefore, it can inform healthcare systems of the subsequent directions to reach the preferred goal.

 

If children with low socio-economic level parents were to grow up in counties with economic connectedness comparable to that of the average child with high level parents, their incomes in adulthood would increase by 20% on average

Social Capital I: Measurement and Associations with Economic Mobility. Raj Chetty, Matthew O. Jackson, Theresa Kuchler, Johannes Stroebel, Nathaniel Hendren, Robert B. Fluegge, Sara Gong, Federico González. NBER Working Paper 30313. July 2022. DOI 10.3386/w30313

Abstract: In this paper—the first in a series of two papers that use data on 21 billion friendships from Facebook to study social capital—we measure and analyze three types of social capital by ZIP code in the United States: (i) connectedness between different types of people, such as those with low vs. high socioeconomic status (SES); (ii) social cohesion, such as the extent of cliques in friendship networks; and (iii) civic engagement, such as rates of volunteering. These measures vary substantially across areas, but are not highly correlated with each other. We demonstrate the importance of distinguishing these forms of social capital by analyzing their associations with economic mobility across areas. The fraction of high-SES friends among low-SES individuals—which we term economic connectedness—is among the strongest predictors of upward income mobility identified to date, whereas other social capital measures are not strongly associated with economic mobility. If children with low-SES parents were to grow up in counties with economic connectedness comparable to that of the average child with high-SES parents, their incomes in adulthood would increase by 20% on average. Differences in economic connectedness can explain well-known relationships between upward income mobility and racial segregation, poverty rates, and inequality. To support further research and policy interventions, we publicly release privacy-protected statistics on social capital by ZIP code at www.socialcapital.org.

Social Capital II: Determinants of Economic Connectedness. Raj Chetty, Matthew O. Jackson, Theresa Kuchler, Johannes Stroebel, Nathaniel Hendren, Robert B. Fluegge, Sara Gong, Federico Gonzalez. NBER Working Paper 30314. July 2022, revised August 2022. DOI 10.3386/w30314

Abstract: Low levels of social interaction across class lines have generated widespread concern and are associated with worse outcomes, such as lower rates of upward income mobility. Here, we analyze the determinants of cross-class interaction using data from Facebook, building upon the analysis in the first paper in this series. We show that about half of the social disconnection across socioeconomic lines—measured as the difference in the share of high-socioeconomic status (SES) friends between low- and high-SES people—is explained by differences in exposure to high- SES people in groups such as schools and religious organizations. The other half is explained by friending bias—the tendency for low-SES people to befriend high-SES people at lower rates even conditional on exposure. Friending bias is shaped by the structure of the groups in which people interact. For example, friending bias is higher in larger and more diverse groups and lower in religious organizations than in schools and workplaces. Distinguishing exposure from friending bias is helpful for identifying interventions to increase cross-SES friendships (economic connectedness). Using fluctuations in the share of high-SES students across high school cohorts, we show that increases in high-SES exposure lead low-SES people to form more friendships with high-SES people in schools that exhibit low levels of friending bias. Hence, socioeconomic integration can increase economic connectedness in communities where friending bias is low. In contrast, when friending bias is high, increasing cross-SES interaction among existing members may be necessary to increase economic connectedness. To support such efforts, we release privacy-protected statistics on economic connectedness, exposure, and friending bias for each ZIP code, high school, and college in the U.S. at www.socialcapital.org.

How does early menopause and menopause symptoms affect women’s careers? The conservative estimate of the cost of early menopause for a woman is £20k, while the cost of suffering an average level of menopause symptoms is £10k

The consequences of early menopause and menopause symptoms for labour market participation. Alex Bryson et al. Social Science & Medicine, Volume 293, January 2022, 114676. https://doi.org/10.1016/j.socscimed.2021.114676

Highlights

• Early natural menopause substantially reduces employment rates among women.

• The number of menopause symptoms women face is also associated with lower employment rates.

• These effects are larger for symptoms which women say “bother me a lot”.

• Psychological problems due to menopause are associated with the biggest employment effects.

Popular version: How does early menopause and menopause symptoms affect women’s careers? Mar 8 2022. https://blog.ukdataservice.ac.uk/how-does-early-menopause-and-menopause-symptoms-affect-womens-careers

Abstract: Using a difference-in-difference estimator we identify the causal impact of early menopause and menopause symptoms on the time women spend in employment through to their mid-50s. We find the onset of early natural menopause (before age 45) reduces months spent in employment by 9 percentage points once women enter their 50s compared with women who do not experience early menopause. Early menopause is not associated with a difference in full-time employment rates. The number of menopause symptoms women face at age 50 is associated with lower employment rates: each additional symptom lowers employment rates and full-time employment rates by around half a percentage point. But not all symptoms have the same effects. Vasomotor symptoms tend not to be associated with lower employment rates, whereas the employment of women who suffer psychological problems due to menopause is adversely affected. Every additional psychological problem associated with menopause reduces employment and full-time employment rates by 1–2 percentage points, rising to 2–4 percentage points when those symptoms are reported as particularly bothersome.

Keywords: MenopauseEarly menopauseMenopausal symptomsVasomotor symptomsEmploymentFull-time employmentBirth cohort

5. Conclusions

Our paper is the first to estimate the effects of early menopause and menopausal symptoms on employment and full-time employment rates among women. We exploit prospective birth cohort data for all women born in a particular week in 1958 to estimate the causal effects of menopause on employment rates using a difference-in-difference strategy. This technique compares the gap in employment rates during their 20s and early 30s with the employment gap in their 50s for women who went onto experience early menopause versus those who did not. We make similar comparisons between women according to the intensity with which they experienced menopausal symptoms when aged 50. In doing so we control for a rich array of variables collected at birth, in childhood, and in early adulthood which can affect employment prospects and experiences of menopause. We show employment and full-time employment trends during their 20s and early 30s did not differ significantly between the ‘treated’ group – those who went on to experience early menopause or more menopausal symptoms – and their ‘control’ groups who did not experience early menopause or did not suffer many menopausal symptoms. This provides some assurance that their employment rates may have trended in similar fashions later in their lives if they had not experienced menopause differently.

We find women's employment rates, and their full-time employment rates fall as the number of menopausal symptoms they report rises. Effects are larger for symptoms that are reported as ‘bothersome’. The effects are quantitatively large. For instance, a woman who experiences the mean number of menopausal symptoms at age 50 can expect to have an employment rate in her 50s that is 4 percentage points lower than a woman who has no menopausal symptoms.

Different types of menopause symptom have different employment effects. For instance, vasomotor symptoms do not affect full-time employment rates, and they only affect employment rates where they are considered ‘bothersome’. In contrast, psychological health problems associated with menopause significantly lower employment and full-time employment rates, and effects are much larger when those symptoms are ‘bothersome’.

Early menopause is associated with a very large (9 percentage point) reduction in employment rates once women reach their 50s, yet it has no statistically significant effect on women's full-time employment rates. It is unclear why early menopause should affect employment rates, but not full-time employment rates. This issue is worthy of further investigation.

It is striking that the inclusion and exclusion of potential confounders makes very little difference to the impact of early menopause and menopause symptoms on employment and full-time employment rates. Even though their inclusion increases the variance in employment rates explained by our models (as indicated by the adjusted R-squared) the coefficient and statistical significance of the interaction capturing the impact of menopause are nearly identical in all cases. Following Oster (2019) we take coefficient stability in the face of adjustments to conditioning covariates as an indication that results are unlikely to be biased by omitted variables.

There are some limitations to this study. First, although women are asked specifically to identify health-related symptoms due to the menopause, in some cases those symptoms may be due to other changes women are going through at the same time which are not directly linked to the menopause. Second, our data only collect information on symptoms related to menopause in the year leading up to the survey interview at age 50. Some women may have experienced symptoms earlier which did not persist to age 50, leading to some error in our ability to accurately capture symptoms related to menopause. Some women who experienced symptoms, but not at age 50, will be misclassified as having no symptoms. However, assuming symptoms experienced earlier than age 50 also have a detrimental impact on employment, this will mean our estimates of symptoms’ effects on employment are downwardly biased. Third, it is worth recalling that the Great Recession hit when the women in the study reached age 50. This was a very severe recession creating what were, at the time, unprecedented labour market problems for many. It would be valuable to see whether our results are replicated in more benign labour market conditions.

These negative employment effects of early menopause and menopausal symptoms are cause for some concern, not only because the size of the effects is large, but also because so many women suffer these problems. As we have shown, the mean number of menopausal symptoms experienced by women in this birth cohort when aged 50 was 8, including 2 particularly ‘bothersome’ symptoms. Five percent of women in the estimation sample had experienced early menopause.

These employment effects of early menopause and menopause symptoms add to the personal costs they have for women suffering from them in terms of their physical and mental health, and potentially their effects on women's private lives, although we do not quantify them here. They also have costs for society, in terms of the health care costs of treating women's symptoms, potential productivity losses from women's lost hours of work and ability to work productively. It is conceivable that they will also affect women's retirement decisions and thus pension entitlements.

Having identified the size and extent of the problem government and employers should consider steps that could be taken to ameliorate the problems women face in their working lives due to the menopause. That said, this is the first study of its kind, so there is value in seeking to replicate and extend research investigating the impact of early menopause and menopausal symptoms on labour market outcomes. First, it would be valuable to know whether the effects we identify might vary for other cohorts of women including more recent entrants to the labour market. Second, there would be value exploring the heterogeneity of menopausal effects and whether there are aspects of women's experiences that may ameliorate the effects of menopause. For instance, it may be that women are better able to manage menopause symptoms where they have greater opportunities to manage working patterns or working hours, as might be the case among self-employed women or employees in workplaces with policies and practices expressly intended to assist women affected by menopause. Third, we know very little about the effects of early menopause and menopausal symptoms on other aspects of women's labour market experiences. We would have a better picture if studies were undertaken to investigate the impacts of menopause on women's wellbeing at work, their job satisfaction and their earnings. Finally, we know of no studies piloting policies or practices in the workplace that might assist women in raising health-related problems they may have during menopause, nor in coping with those problems. These evaluations are needed to provide the evidence base employers and government need so they know what actions to take to improve women's working lives.

Men, particularly those who declare being interested in politics, take longer than women to admit that they do not know the answer to political knowledge items

How long does it take to admit that you do not know? Gender differences in response time to political knowledge questions. Mónica Ferrín, Gema García-Albacete, Irene Sánchez-Vítores. Research & Politics, August 5, 2022. https://doi.org/10.1177/20531680221117454

Abstract: The implications of the persistent gender gap in political knowledge are a puzzle that the literature is still disentangling; and research has evidenced important differences in the way women and men respond to survey questions. We argue in this article that political knowledge survey items not only inform about differences in cognition but also about other latent traits related to gender stereotyping. Gender stereotypes around political knowledge push men to be knowledgeable but not so much women, which we expect to affect men and women’s survey responses differently. To test this expectation, we explore response times of do not know answers to political knowledge items. Our results show that men, particularly those who declare being interested in politics, take longer than women to admit that they do not know the answer to political knowledge items.

Keywords: political knowledge, do not know, gender gap, response time, stereotypes

Final remarks

This article contributes to the literature on gender and politics by showing that gender-conformity affects both men and women. Our interpretation of the longer time men take to respond DK is that men are gender stereotyped to be politically knowledgeable. As a consequence, they are reluctant to verbalize their lack of knowledge, which implies that they take as much time as possible before yielding and admitting they do not know the answer.

While some authors have argued that do not know answers simply reflect ignorance on behalf of respondents, regardless of the question format or their personality traits (Jessee, 2017; Luskin and Bullock, 2011), this article shows that DK responses do not distribute randomly. Gender differences in DK response latencies provide an additional piece of evidence regarding the effects of stereotype threat on respondents (Davis and Silver, 2003; Pereira, 2019) and how it results in a further overestimation of men’s actual levels of political knowledge, compared to women’s. Further research should explore the extent to which priming other social identities (McGlone et al., 2006; Shih et al., 1999), amongst other strategies, could enhance respondent’s confidence and provide more accurate depiction of what they know about politics.

This article also opens an avenue for further research on survey methodology. We have shown that response latencies of do not know answers hide differentiated traits for women and men, based on gender stereotypes. To date, little research has explored the potential interpretation of groups’ differences in response times in relation to data quality and comparability. We offer here evidence that response times differ significantly between women and men, which implies different reactions to survey items. This finding should encourage the use of response latencies as a tool to explore heterogeneity in responses to survey items.

In contrast to many other growth models we find that the taxation of human capital has a substantial negative effect on its accumulation; this in turn reduces innovation and, consequently, the income growth rate

Human capital, innovation, and growth. Clas Eriksson, Johan Lindén, Christos Papahristodoulou. International Journal of Economic Theory, May 16 2022. https://doi.org/10.1111/ijet.12346

Abstract: This paper explores the interaction between human capital and innovation in the process of economic growth. Using a model of endogenous growth, we focus on how taxes and other policy instruments affect the incentives to invest in human capital. In contrast to many other growth models we find that the taxation of human capital has a substantial negative effect on its accumulation. This in turn reduces innovation and, consequently, the income growth rate. More surprisingly, other policies that are intended to stimulate growth may have opposing effects on innovation and the accumulation of human capital. For example, while subsidies to research and to intermediate inputs do have positive effects on innovation and growth, they lead to a lower stock of human capital, in the empirically relevant case when the elasticity of intertemporal substitution in consumption is low.

6 CONCLUSIONS

Human capital and innovation are important drivers of economic growth. This paper explores a model in which both the acquirement of human capital and innovation are endogenous, and where a share of the human capital is used in research. We examine the incentives to undertake research and spend time in schooling, in particular with respect to the role of economic policy for those growth-promoting activities.

We develop a model similar to Romer (1990), with the important difference that human capital is endogenous. In addition, contrary to the simpler standard formulation in many other growth models where labor taxes drop out of the equations, our household's optimization implies that the taxation on human capital has a substantial negative effect on the formation of this factor. Since human capital is an essential input in research, this in turn lowers the income growth rate. Similarly, if the tax on unskilled labor is higher, more time will be spent in schooling to build human capital, resulting in a higher growth rate.

While subsidies to research and to intermediate inputs have positive effects on growth, they do not necessarily lead to a larger long-run stock of human capital in the economy. If the elasticity of intertemporal substitution in consumption is sufficiently low, these policy instruments stimulate growth by inducing a reallocation of a smaller stock of human capital toward more research.

An economy which taxes interest income at a higher rate will experience lower growth, because the representative household decides to shift some consumption from the future to the present in response to the lower net interest rate. The total stock of human capital is lower on the BGP and the relative wage increases.

Our model implies a substantial negative tax effect on economic growth. The analysis thus indicates that the design of the tax system may be important for the rate of growth in an economy. This theoretical finding is consistent with some important recent empirical research.

Impression formation at zero-acquaintance: Penises which were wider, longer, and moderately hairy were perceived more positively in terms of personality and sexual appeal; shorter and narrower penises were perceived as more neurotic

Personality and Sexual Perceptions of Penises: Digital Impression Formation. Thomas R. Brooks & Stephen Reysen. Sexuality & Culture, Aug 4 2022. https://rd.springer.com/article/10.1007/s12119-022-10000-y

Abstract: Dating app users are likely to experience a high frequency of viewing the sexually explicit material of potential partners prior to a physical meeting. The present study aimed to investigate what information is inferred from a picture of a penis at zero-acquaintance. Past research in impression formation at zero-acquaintance has demonstrated a stability with regard to personality and trait perceptions of faces. Utilizing 106 participants, our study extends this paradigm by testing the hypothesis that penis prototypicality would be associated with attractiveness, as well as explore the personality and sexual perceptions of penises along the dimensions of girth, length, and amount of pubic hair. The hypotheses were confirmed and the analysis of penis dimensions revealed strong results. Penises which were wider, longer, and moderately hairy were perceived more positively in terms of personality and sexual appeal. Shorter and narrower penises were perceived as more neurotic. The results demonstrate the function of impression formation within the digital sexual landscape with regard to sexually explicit material.

Free-ranging long-tailed macaques: Do monkeys use sex toys? Evidence of stone tool-assisted masturbation.

Do monkeys use sex toys? Evidence of stone tool-assisted masturbation in free-ranging long-tailed macaques. Camilla Cenni,Jessica B. A. Christie, Yanni Van der Pant, Noëlle Gunst, Paul L. Vasey, I Nengah Wandia, Jean-Baptiste Leca. Ethology, August 4 2022. https://doi.org/10.1111/eth.13324

Abstract: Recent reports on tool use in nonforaging contexts have led researchers to reconsider the proximate drivers of instrumental object manipulation. In this study, we explore the physiological and behavioral correlates of two stone-directed and seemingly playful actions, the repetitive tapping and rubbing of stones onto the genital and inguinal area, respectively, that may have been co-opted into self-directed tool-assisted masturbation in long-tailed macaques (i.e., “Sex Toy” hypothesis). We predicted that genital and inguinal stone-tapping and rubbing would be more closely temporally associated with physiological responses (e.g., estrus in females, penile erection in males) and behavior patterns (e.g., sexual mounts and other mating interactions) that are sexually motivated than other stone-directed play. We also predicted that the stones selected to perform genital and inguinal stone-tapping and rubbing actions would be less variable in number, size, and texture than the stones typically used during other stone-directed playful actions. Overall, our data partly supported the “Sex Toy” hypothesis indicating that stone-directed tapping and rubbing onto the genital and inguinal area are sexually motivated behaviors. Our research suggests that instrumental behaviors of questionably adaptive value may be maintained over evolutionary time through pleasurable/self-rewarding mechanisms, such as those underlying playful and sexual activities.

Naturism & Casual Stripping Predict Social Body Appreciation & less social physique anxiety; sexting predicts social physique anxiety in men

Good Nudes and Bad Nudes: How Naturism, Casual Stripping, and Sexting Predict Social Physique Anxiety and Body Appreciation. Keon West & Eliza Kukawska. Sexuality & Culture, Aug 5 2022. https://rd.springer.com/article/10.1007/s12119-022-09990-6

Abstract: Prior research suggests that naturism leads to less social physique anxiety and more positive body image, but that other forms of public nudity (e.g., casual stripping, sexting) may be harmful, particularly for women. Two cross-sectional studies built on those previous findings. Study 1 (N1 = 6670) found a positive relationship between generalised nude activity and body appreciation which was not moderated by gender. Study 2 (N2 = 331) found that both naturism and casual stripping predicted more body appreciation, a relationship mediated by less social physique anxiety. Again, these relationships were not moderated by gender. In contrast, sexting did not predict body appreciation and predicted more social physique anxiety, but only in men. These findings highlight that some types of nudity may be more beneficial or harmful than others, and that future research and policy should specify the type of nudity under consideration in order to maximise positive effects.

General Discussion

These two studies replicated, clarified, and built on previous findings concerning nudity and psychological outcomes. Using a large, age-diverse and gender-diverse sample, Study 1 found that participation in public nudity generally predicted more positive body image (i.e., higher levels of body appreciation). Furthermore, the lack of moderation by gender, despite the substantial sample size in that study, is a strong indicator that this moderation may be very small or genuinely absent. The positive associations between public nudity and body image appear to apply for those who identify as men, women, or neither.

Study 2 extended these findings by investigating three specific types of public nudity simultaneously: naturism, casual stripping, and sexting. In line with prior research (West, 2021) naturism predicted more body appreciation, and that this relationship was mediated by lower levels of social physique anxiety. Seemingly in contrast with prior research (Sherman & Hackathorn, 2020), casual stripping was also associated with positive outcomes: less social physique anxiety and (indirectly) more body appreciation. As in Study 1, these positive associations were not moderated by gender. Only sexting was associated with negative outcomes and this was the only association moderated by gender: sexting predicted more social physique anxiety in men (but not in women) and had no relationship with body appreciation. Below, we discuss these findings considering their implications, strengths and limitations, and suggestions for future research.

Implications

The positive effects of naturism on body image have been already documented in previous research (e.g., West, 2018, 2020, 2021). Nonetheless, these findings add to the generalisability of the relationship between naturism and body image. In particular, Study 1 used a very large sample of German participants, and Study 2 used a sample of mixed European participants. The consistency between these findings and prior research can increase our confidence about the positive effects of naturism, and the generalisability of these effects beyond a limited range of English-speaking countries.

Perhaps more surprising, these findings appear to contradict previous research which found that casual stripping was associated with negative (not positive) psychological factors (i.e., Sherman & Hackathorn, 2020). However, we can propose some potential reasons for these divergent findings. First, as mentioned before, Sherman and Hackathorn’s measure of casual stripping included items that could have applied to other forms of public nudity, making it unclear exactly what the scale was measuring. Second, Sherman and Hackathorn investigated different variables. Specifically, they found (1) associations between casual stripping and paternal neglect (which seemed to be a precursor and not consequence of casual stripping) and (2) associations between casual stripping and sociosexuality, a variable that can only be interpreted as negative if one holds a priori beliefs about the value of a woman’s modesty and sexual selectivity. It seems quite reasonable to interpret their findings differently, in line with prior research (e.g., Lewis & Janda, 1988) that found positive associations between nudity and comfort with one’s sexuality. In that light, it is also understandable that casual stripping may be similarly associated with lower levels of social physique anxiety and higher levels of body image in both men and women. In any case, research on stripping and psychological outcomes remains scarce and somewhat unclear, with some finding associations even between professional stripping and positive psychological outcomes (see, e.g., Sweet & Tewksbury, 2000; Wood, 2000). Thus, future research could be useful to clarify what the positive and negative effects of stripping may be.

Only one finding indicated associations between some form of public nudity and negative psychological outcomes (i.e., the association between sexting and social physique anxiety) and this finding only applied to men. While these findings do not go beyond prior research showing that sexting was sometimes associated with negative outcomes (Liong & Cheng, 2019), they do add meaningfully to these current findings in two ways. First, they clarify that not all forms of public nudity have similar associations with psychological outcomes; while naturism and casual stripping were associated with positive outcomes, sexting was associated with negative outcomes. Second, they undermine the simplistic interpretation of our findings that high levels of body image and low levels of anxiety about one’s body are necessarily the causes of more involvement in public nudity. At the very least, lower levels of anxiety about one’s body is associated with less frequent sexting (though more frequent naturism and casual stripping) suggesting that a more complex relationship exists between nudity and body image.

Finally, though this was not a central aspect of the study, it is noteworthy that a large proportion of the participants in both studies had engaged in some communal nude activity (Study 1 – 46%, Study 2 – 88% naturism, 62% casual stripping, 57% sexting). This suggests that willingness to take part in nude activity may be more widespread than it is often assumed to be.

Limitations and Future Research

These studies benefit from a number of strengths including theoretical replication across two studies, a very large sample size in Study 1, participants of varied nationalities, and participants who were more diverse than the widely overused student samples common in social psychology (Henrich, Heine, & Norenzayan, 2010). Practically, this research also provides a valuable tool for assessing body image in German-speaking countries by using the translation of the most recent version of the BAS-2, which has several advantages over the previous versions of the Body Appreciation Scale (Tylka & Wood-Barcalow, 2015a).

However, this research also has limitations. As both studies are cross-sectional, it is not possible to infer causal effects. Thus, a potential criticism is that this research merely shows that people who like their bodies are more likely participate in nudity. While it is plausible that a causal relationship exists in that direction, neither these current data nor prior research support the simplistic interpretation that this is the only causal relationship. As mentioned, this interpretation is incompatible with the finding that less anxiety about one’s body is associated with more of some forms of public nudity (naturism and casual stripping), but less of other forms (sexting). Furthermore, prior experimental research has shown a causal effect of public nudity on social physique anxiety and body image (West, 2021).

While the participants were diverse in some ways, most participants identified as White, and sexual orientation and cisgender or transgender status was not explicitly investigated. Also, despite the large samples, some amount of self-selection likely occurred, meaning that only participants were likely already interested in body image. Similar limitations found in other research on nudity and body image (West, 2018, 2020, 2021). Nonetheless, future research should specifically investigate whether the effects of public and communal nudity differ for participants who are not White, cisgender, and heterosexual.

We note that the effect size of the relationship between nude activity and body image in Study 1 was quite small. However, this could be due to the use of a relatively crude all-or-nothing measure of participation in nude activity; participants merely indicated (“yes” vs. “no”) whether they had ever taken part in such activity. Effect sizes were notably larger in Study 2, in which we used more nuanced measures. This further suggests that even more nuanced studies that include measures of how frequently, recently, or under what conditions participants took part in such activities may yield yet larger effect sizes, as well as more information about the ways to maximise the link between nudity and body appreciation.

Finally, though this research investigated specific, positive relationships between nude activities and body appreciation, future research should also continue to investigate the possible relationships between nude activity and negative outcomes. Several potential outcomes were not included in this research, such as body shame, body surveillance, overall life satisfaction, or even self-esteem. Including such outcomes may provide a more rounded picture of the positive and negative effects of all these activities.