Friday, August 7, 2020

Rather than the crisis fundamentally changing people psychologically, genetic differences between individuals seem to play a fundamental role in shaping psychological & behavioural responses to the COVID-19 crisis

Genetic correlates of psychological responses to the COVID-19 crisis in young adult twins in Great Britain. Kaili Rimfeld et al. Aug 2020. https://doi.org/10.21203/rs.3.rs-31853/v1

Abstract: We investigated how the COVID-19 crisis and the extraordinary experience of lockdown affected young adults in England and Wales psychologically. One month after lockdown commenced (T2), we assessed 30 psychological and behavioural traits in 4,000 twins in their mid-twenties and compared their responses to the same traits assessed in 2018 (T1). Mean changes from T1 to T2 were modest and inconsistent: just as many changes were in a positive as negative direction. Twin analyses revealed that genetics accounted for about half of the reliable variance at T1 and T2. Genetic factors correlated on average .86 between T1 and T2 and accounted for over half of the phenotypic stability. Systematic environmental influences had negligible impact on T1, T2 or T2 change. Rather than the crisis fundamentally changing people psychologically, our results suggest that genetic differences between individuals play a fundamental role in shaping psychological and behavioural responses to the COVID-19 crisis.

Keywords: COVID-19, lockdown, psychological and behavioural traits, twins, young adults, England and Wales


Discussion
How much has the COVID-19 crisis changed young adults psychologically following the unprecedented social experiment of one month of lockdown? As expected, the 30 measures in our study yielded many statistically significant changes in means. The largest changes in the negative direction were reduced volunteering and achievement motivation and increased hyperactivity-inattention. However, there were as many changes in the positive direction, most notably, reduced verbal peer victimisation. Changes were similar in direction and magnitude for males and females, with the single exception of general anxiety, which increased more for females than males. However, most of these mean changes have modest effect sizes, with an average of 0.24. Although we expected that the crisis would affect some individuals more than others, we found no increase in variance at T2.  It is possible that the effects of the crisis will hit harder later or that longer lockdown or the economic aftermath of the crisis will have a greater effect. We will investigate these possibilities with three follow-up surveys during 2020.

Why do these young adults in Great Britain show modest negative effect on average after being in lockdown for one month when it is generally assumed that the psychological effects will be substantial? Part of the answer is that research often focuses on statistical significance and mean differences rather than considering effect size and individual differences. With our large sample size, nearly all variables show significant mean differences, but they don’t make much of a difference, accounting for less than two percent of the variance on average. Another reason might be methodological. In the present study we did not focus on participants’ subjective reports of how the COVID-19 crisis changed them. Instead, at T2, we asked participants to report, for example, how depressed they felt during the month following lockdown, which we compared to their reports of depression on the same measures in 2018. We found no difference in depression on average.

Other reasons why we found few negative effects of the COVID-19 crisis could be that the lockdown was so widespread (we’re all in it together spirit?) or that our participants are British (stiff upper lip?) or that they are young adults (resilience? insouciance?). Concerning the insouciance hypothesis, we asked participants at T2 how much they were worried about their physical health and mental health during the month since lockdown. The frequency of those reporting that they were moderately, very, or extremely worried was 38% for physical health and 57% for mental health. In other words, they were, quite reasonably, worried, although on average they did not change psychologically, including their symptoms of general anxiety. This can be viewed as a hopeful message that young people on average, are resilient psychologically to an experience as seismic as COVID-19 and lockdown, although these mean differences mask individual differences to the COVID-19 and lockdown. It remains to be seen if similar results emerge in other countries, at other ages and after longer exposure to the crisis and its aftermath.

The focus of our study was on individual differences rather than mean differences. How much has COVID-19 shuffled the deck of individual differences? The rank order of individual differences was largely stable from T1 to T2, with stability accounting for about 70% of the reliable variance at T1 and T2 on average across the measures. From a genetic perspective, the most interesting finding was that the average genetic correlation was 0.86, indicating that genetic effects at T1 were highly correlated with genetic effects at T2, despite the intervening COVID-19 crisis and lockdown. It is also interesting that T2 changes, which are independent of T1, show genetic influence.

We conclude that inherited DNA differences are the major systematic force shaping individual differences in psychological traits at T2 as well as at T1. Genetic effects account for about half of the reliable psychological differences between people at T1 and T2. The environment accounts for the rest of the variance, but it is not the systematic effect of environmental factors often assumed to be important, such as shared family environment. Environmental factors of this systematic sort had negligible effects on variance at T1 and T2 and for T2 change. The environmental effects that make a difference are those that are not shared by twin siblings growing up in the same family or, in our study, by twins locked down together. These idiosyncratic ‘non-shared’ environmental factors are likely to be unsystematic, chance experiences (Plomin, 2018).

Our results confirmed seven of our eight pre-registered (https://osf.io/r58be/) hypotheses. This speaks to the replicability of findings from behavioural genetic research on which these hypotheses were based, which is noteworthy given the replication crisis in science in general and in psychology in particular (Plomin et al., 2016). The exception was the hypothesis that variance at T2 would be greater than at T1, which was a prediction not based on behavioural genetic research. The consistency of results from T1 to T2 also attests to the replicability of research in behavioural genetics.

Concluding that inherited DNA differences are the major systematic force shaping who we are psychologically does not imply that novel environmental interventions, including therapeutic interventions, cannot make a difference. It should be emphasised that heritability does not imply immutability.

Heritability is a descriptive statistic limited to a particular population at a particular time with a particular mix of genetic and environmental influences. Our study can be seen as an attempt to assess whether heritability changed as a function of a tectonic shift in environment, the COVID-19 crisis.

Concluding that the COVID-19 crisis has not fundamentally changed these young people psychologically is not to dismiss the pain some of them felt before or during the crisis, or will continue to feel after the crisis ends. Even though the crisis had little effect on means and even less effect on variances and covariances, genetically driven psychological vulnerabilities are especially important targets for preventive interventions in young adults because the twenties is a pluripotent tipping point for life-long psychological problems (Arnett, 2014; Smith et al., 2011).

Imagining the future, remembering the past: Future events were simulated at proportionally higher speed than past events; the density of experience units representing the unfolding of events was lower for future episodes

The temporal compression of events during episodic future thinking. Olivier Jeunehomme, Nathan Leroy, Arnaud D'Argembeau. Cognition, August 6 2020, 104416. https://doi.org/10.1016/j.cognition.2020.104416

Highlights
• The unfolding of real-world events is temporally compressed in future simulations.
• Compression rates are higher for future than past events.
• Compression rates are lower for actions than spatial displacements.
• Temporal compression depends on the density of represented experience units.
• Experience units serve as an index for estimating past and future event durations.

Abstract: While the cognitive and neural mechanisms that underlie episodic future thinking are increasingly well understood, little is known about how the temporal unfolding of events is represented in future simulations. In this study, we leveraged wearable camera technology to examine whether real-world events are structured and compressed in the same way when imagining the future as when remembering the past. We found that future events were simulated at proportionally higher speed than past events and that the density of experience units representing the unfolding of events was lower for future than for past episodes. Despite these differences, the nature of events influenced compression rates in the same way for past and future events. Furthermore, the perceived duration of both types of events depended on the density of represented experience units. These results provide novel insight into the mechanisms that structure the unfolding of events during future simulations.

Keywords: Episodic memoryEpisodic future thinkingTemporal compressionTime estimationWearable camera



Trait mindfulness do not reliably translate into a pattern of healthful behaviours in general, although trait mindfulness shows a stronger associations with health behaviours under certain conditions

Trait mindfulness and health behaviours: a meta-analysis. Margarita Sala ,Catherine Rochefort,P. Priscilla Lui &Austin S. Baldwin. Health Psychology Review, Volume 14, 2020 - Issue 3, Pages 345-393, Aug 11 2019. https://doi.org/10.1080/17437199.2019.1650290

ABSTRACT: Mindfulness is defined as bringing one’s attention to present-moment experience with acceptance, and is associated with engagement in various health behaviours. To synthesise and evaluate this literature, we conducted a comprehensive meta-analytic review and examined (a) the associations between trait mindfulness and health behaviours and (b) the extent to which these associations were moderated by study and individual differences. A total of 125 independent samples were included (N = 31,697, median male percentage = 38.8%, median age = 28.3). A multilevel random-effects model was used to estimate summary study-level effect sizes, and multilevel mixed-effects models were used to examine moderator effects. Mindfulness had a positive and small association with aggregated health behaviours (r = .08). Mindfulness was positively associated with physical activity, healthy eating, and sleep (rs = .08–.14), and negatively associated with alcohol use (r = −.06). Effects were larger for health promoting behaviours, the acting with awareness facet of mindfulness, and samples involving psychiatric patients. Although findings indicate that individual differences in trait mindfulness do not reliably translate into a pattern of healthful behaviours in general, trait mindfulness shows a stronger associations with health behaviours under certain conditions.

KEYWORDS: Mindfulness, physical activity, healthy eating, sleep, substance use


Increasing Population Densities Predict Decreasing Fertility Rates over Time: A 174-nation Investigation

Rotella, Amanda M., Michael E. W. Varnum, PhD, Oliver Sng, and Igor Grossmann. 2020. “Increasing Population Densities Predict Decreasing Fertility Rates over Time: A 174-nation Investigation.” PsyArXiv. August 5. doi:10.31234/osf.io/zpc7t

Abstract: Fertility rates have been declining worldwide over the past five centuries, part of a phenomenon known as “the demographic transition”. Prior work suggests that this decline is related to population density, however to date this work has either been largely atheoretical or cross sectional. We draw on life history theory to examine the relationship between population density and fertility over time both within and between countries across 174 countries over 69 years (1950 to 2019) using annual data. Using state-of-the-art methods, we find a robust relationship between density and fertility; increased population densities are associated with lower fertility rates, controlling for a variety of socioeconomic, socioecological, geographic, cultural, population-based, and female empowerment related variables. Importantly, we also generate predictions about the conditions in which this effect should be stronger vs. weaker. Consistent with these predictions, we find that where conditions are harsh and favor engagement in shorter-term strategies (i.e., high homicide rates, low GDP per capita, high economic inequality, and high pathogen prevalence), the effect of increased population density on fertility rates is attenuated. We also find that the density-fertility relationship is moderated by religiousness and strength of social norms. These findings shed new light on why, and under what conditions, rising population densities influence fertility rates.


Intelligence manifests itself in the brain in breaking a problem down into multiple subtasks, which are worked on in widely distributed processing units, showing signs of being focused on the common plan

Integrated Intelligence from Distributed Brain Activity. John Duncan, Moataz Assem, Sneha Shashidhara. Trends in Cognitive Sciences, August 5 2020. https://doi.org/10.1016/j.tics.2020.06.012

Highlights
.  Fluid intelligence tests predict success in many activities, suggesting cognitive mechanisms of broad importance.
.  We propose a core process of attentional integration. Complex problems must be segmented into simpler parts. Attention to each part integrates cognitive fragments into a computational structure.
.  Fluid intelligence is linked to the brain’s multiple-demand (MD) system, defined by common activity across different cognitive demands. Across the brain, MD patches shows anatomical and physiological properties adapted to attentional integration.
.  Neurophysiology of putative MD regions shows adaptive coding of task-relevant information. Suiting attentional integration, many neurons show conjunctive coding (e.g., binding cognitive operations to their target objects).
.  In broad outline, these results suggest how distributed brain activity builds organized cognition.

Abstract: How does organized cognition arise from distributed brain activity? Recent analyses of fluid intelligence suggest a core process of cognitive focus and integration, organizing the components of a cognitive operation into the required computational structure. A cortical ‘multiple-demand’ (MD) system is closely linked to fluid intelligence, and recent imaging data define nine specific MD patches distributed across frontal, parietal, and occipitotemporal cortex. Wide cortical distribution, relative functional specialization, and strong connectivity suggest a basis for cognitive integration, matching electrophysiological evidence for binding of cognitive operations to their contents. Though still only in broad outline, these data suggest how distributed brain activity can build complex, organized cognition.

Keywords: intelligenceattentioncognitive controlbrain networksneural coding


Concluding Remarks and Future Directions

Many issues are raised by the integration account. Here we discuss two: the interface of short-term cognitive activity and long-term knowledge, and the nature of attentional capacity limitations.
As implied by our discussion of positive manifold, a core question is interface between on-line cognition and long-term knowledge. As in classical symbolic artificial intelligence (e.g., [97]), a complex problem is divided into simple parts on the basis of long-term knowledge of the structure of the world and relations within it. It is knowledge that tells us how travel to Japan can be divided into component steps, how a useful move can be made in proving a mathematical theorem, or where we should look in seeking a solution to a spatial puzzle. In the brain, knowledge that might shape current cognition is distributed across multiple brain systems. Semantic memory, for example, may be based around a proposed hub in the temporal pole [98], while episodic memory, spatial knowledge, and social knowledge are linked to distinct components of the default mode network [99]. To understand MD activity in constructing solutions to cognitive problems, we need to know how multiple aspects of knowledge feed into this process. Again, this is reminiscent of the widespread connectivity of MD regions (Figure 5) and our finding that multiple networks have representatives in the MD penumbra.
In classical artificial intelligence, problem solutions were often built up in an unlimited working memory, keeping track of a progressively more complex structure of goals and subgoals. For biological cognition this is not plausible; for goals such as travel to Japan or solving a scientific problem, only a small fraction can be represented in active neural firing at any one time, with the rest of the structure in long-term memory, ready for retrieval when required. At the same time, the current active focus of attention must remain bound to the long-term structure, so that, for example, a failure to progress to a goal by one route can trigger a search for an alternative. The issue is reminiscent of recent biological accounts of working memory, combining active neural firing with storage through short-term synaptic change [100,101]. It is presently unknown how the focus of attention in active cognition can be situated within a complex, long-term representation of the larger-scale problem.
A further open issue concerns the well-known capacity limitations of ‘attention’, reflected in difficulty carrying out several tasks at once [102,103]. Shared demands on MD activity could provide an obvious basis for such limits and, indeed, various authors have linked capacity limitations to the functions of frontal and parietal cortex [16,22,104,105]. Such proposals find support in neurophysiological studies, showing that, in frontal and parietal cortex, there is interference between representations of different visual stimuli [106], working memory items [107], or task components [86,108]. Further work is needed, however, to understand the physiological basis of this interference. In the visual system, capacity limits in representing multiple stimuli are thought to arise through a process of competition or divisive normalization [109.110.111.]. In such models, each stimulus attempts to drive the activity of a neuron to a particular value, appropriate to representing the properties of this stimulus; with multiple stimuli in the field, opposing forces bring activity to a compromise value, reducing the fidelity of representation for any one. Similar patterns can be seen in the visual responses of prefrontal neurons [112,113], raising the possibility that divisive normalization is a general principle in MD cortex. Recurrent neural networks have become popular as models of working memory and cognitive control (e.g., [114]), and in a recent model, divisive normalization is the basis for limited working memory capacity [115]. Further experimental work is needed to test whether divisive normalization models may be extended to the broader attentional limits of MD activity and cognitive control.
Of course, our account of cognitive integration leaves much unknown. That said, like an early map of the globe, it provides an outline sketch of how distributed brain activity can assemble complex cognition. This sketch, we suggest, provides the skeleton we need to guide future, more detailed physiological study (see Outstanding Questions).



Outstanding Questions
How do different MD regions interact? Across the extended MD system, we know little of the dynamics of information representation and exchange during task performance. The very different connectivities of MD regions imply separate functional contributions to cognitive integration, but in fMRI, the dominant picture is one of corecruitment. This picture may reflect the low temporal resolution of fMRI, rendering the method blind to high-speed information development and exchange. Elucidating how task-relevant information arises and is distributed across the network calls for simultaneous electrophysiological recordings in separate MD regions, either in experimental animals or patients implanted for intracranial recordings.
How does MD activity bind together coherent processing across multiple brain regions? Again, this calls for electrophysiological studies, addressing questions that include directional information flow at different stages of a cognitive operation, and the role of precise timing relations (e.g., oscillatory synchrony) across brain regions.
How are brief segments of cognition combined into complex goal–subgoal structures? For example, we know little of how sustained goal maintenance directs brain activity in pursuit of a series of subgoals. Especially for complex behavior, a critical question is interaction between immediate cognitive activity and long-term knowledge of goals, subgoals, and their relationships.
What is the role of prominent MD foci seen outside cerebral cortex, especially in caudate and cerebellum? Almost nothing is known of cortical-subcortical and cerebro-cerebellar interaction as cognitive operations are carried out. High-field imaging may bring the spatial resolution needed for studies of small subcortical structures.

Creative behaviors seem to yield survival & reproductive benefits; however, individuals often have to violate social norms; this deviance entails consequences detrimental for both survival and reproduction

The paradox of creativity. Eric Bonetto et al. New Ideas in Psychology, Volume 60, January 2021, 100820. https://doi.org/10.1016/j.newideapsych.2020.100820

Highlights
• Creative behaviors seem to yield survival and reproductive benefits.
• However, to be creative, individuals often have to violate social norms.
• This deviance entails consequences detrimental for both survival and reproduction.
• We propose to call this paradox the paradox of creativity.

Abstract: Creativity seems to yield survival and reproductive benefits. Creative behaviors allow individuals to solve problems in new and appropriate ways, and thus to promote their survival. They also facilitate bonding and constitute a signal of one's fitness, favoring attraction of mates. However, to be creative, individuals often have to violate social norms in order to promote change. So far, this deviance induced by creative behaviors had not been seen as an adaptive disadvantage. This deviance entails negative consequences as social exclusion or ostracism, which are detrimental for both survival (e.g., reduced access to resources within the group) and reproduction (reduced reproductive fitness). Thus, the adaptive benefits yielded by creativity have to be nuanced by these potential disadvantages. The paradox of creativity proposes a finer-grained vision of the adaptive reasons why creativity has been maintained within the human species, has evolved, and is collectively regulated. Research perspectives are also proposed.

Keywords: Evolutionary perspectiveCreativityParadox of creativity




Thursday, August 6, 2020

From 2012... Comparative Environmental Life Cycle Assessment of Conventional and Electric Vehicles

From 2012... Comparative Environmental Life Cycle Assessment of Conventional and Electric Vehicles. Troy R. Hawkins, Bhawna Singh, Guillaume Majeau-Bettez, and Anders Hammer Strømman. Journal of Industrial Ecology, Volume 17, Number 1, Oct 12 2012. https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1530-9290.2012.00532.x

Summary: Electric vehicles (EVs) coupled with low-carbon electricity sources offer the potential for reducing greenhouse gas emissions and exposure to tailpipe emissions from personal transportation. In considering these benefits, it is impor tant to address concerns of problem-shifting. In addition, while many studies have focused on the use phase in comparing transportation options, vehicle production is also significant when comparing conventional and EVs. We develop and provide a transparent life cycle inventory of conventional and electric vehicles and apply our inventory to assess conventional and EVs over a range of impact categories. We find that EVs powered by the present European electricity mix offer a 10% to 24% decrease in global warming potential (GWP) relative to conventional diesel or gasoline vehicles assuming lifetimes of 150,000 km. However, EVs exhibit the potential for significant increases in human toxicity, freshwater eco-toxicity, freshwater eutrophication, and metal depletion impacts, largely emanating from the vehicle supply chain. Results are sensitive to assumptions regarding electricity source, use phase energy consumption, vehicle lifetime, and battery replacement schedules. Because production impacts are more significant for EVs than conventional vehicles, assuming a vehicle lifetime of 200,000 km exaggerates the GWP benefits of EVs to 27% to 29% relative to gasoline vehicles or 17% to 20% relative to diesel. An assumption of 100,000 km decreases the benefit of EVs to 9% to 14% with respect to gasoline vehicles and results in impacts indistinguishable from those of a diesel vehicle. Improving the environmental profile of EVs requires engagement around reducing vehicle production supply chain impacts and promoting clean electricity sources in decision making regarding electricity infrastructure.

Keywords: batteries, electricity mix, global warming, industrial ecology, life cycle inventory (LCI), transportation

Check also China’s booming electric vehicle market is about to run into a mountain of battery waste. By Echo Huang. Quartz, September 28, 2017. http://www.bipartisanalliance.com/2017/10/chinas-booming-electric-vehicle-market_14.html

And How many electric vehicles can the current Australian electricity grid support?, Li and Lenzen, International Journal of Electrical Power & Energy Systems, Volume 117, May 2020. https://www.bipartisanalliance.com/2020/01/how-many-electric-vehicles-can-current.html

And Leading scientists set out resource challenge of meeting net zero emissions in the UK by 2050. National History Museum, Jun 5 2019. https://www.bipartisanalliance.com/2019/06/to-replace-all-uk-based-vehicles-today.html:
my summary: To replace all UK-based vehicles today with electric vehicles would take near 2 times the total annual world cobalt production, nearly the world's neodymium & dysprosium, 3/4 the world’s lithium & at least 1/2 the world’s copper in 2018 
Also: "The worldwide impact: If this analysis is extrapolated to the currently projected estimate of two billion cars worldwide, based on 2018 figures, annual production would have to increase for neodymium and dysprosium by 70%, copper output would need to more than double and cobalt output would need to increase at least three and a half times for the entire period from now until 2050 to satisfy the demand."

How much are electric vehicles driven? Lucas W. Davis. Applied Economics Letters, Feb 20 2019. https://www.bipartisanalliance.com/2019/02/the-prospect-for-electric-vehicles-as.html

The incidence rate of dementia in Europe and North America has declined by 13% per decade over the past 25 years, consistently across studies; incidence is similar for men and women

Twenty-seven-year time trends in dementia incidence in Europe and the United States. The Alzheimer Cohorts Consortium, Frank J. Wolters et al. Neurology, August 04, 2020; 95 (5). https://doi.org/10.1212/WNL.0000000000010022

Abstract
Objective To determine changes in the incidence of dementia between 1988 and 2015.

Methods This analysis was performed in aggregated data from individuals >65 years of age in 7 population-based cohort studies in the United States and Europe from the Alzheimer Cohort Consortium. First, we calculated age- and sex-specific incidence rates for all-cause dementia, and then defined nonoverlapping 5-year epochs within each study to determine trends in incidence. Estimates of change per 10-year interval were pooled and results are presented combined and stratified by sex.

Results Of 49,202 individuals, 4,253 (8.6%) developed dementia. The incidence rate of dementia increased with age, similarly for women and men, ranging from about 4 per 1,000 person-years in individuals aged 65–69 years to 65 per 1,000 person-years for those aged 85–89 years. The incidence rate of dementia declined by 13% per calendar decade (95% confidence interval [CI], 7%–19%), consistently across studies, and somewhat more pronouncedly in men than in women (24% [95% CI 14%–32%] vs 8% [0%–15%]).

Conclusion The incidence rate of dementia in Europe and North America has declined by 13% per decade over the past 25 years, consistently across studies. Incidence is similar for men and women, although declines were somewhat more profound in men. These observations call for sustained efforts to finding the causes for this decline, as well as determining their validity in geographically and ethnically diverse populations.

The Origin of Our Modern Concept of Depression—The History of Melancholia From 1780-1880

The Origin of Our Modern Concept of Depression—The History of Melancholia From 1780-1880: A Review. Kenneth S. Kendler.
JAMA Psychiatry. 2020;77(8):863-868. doi:10.1001/jamapsychiatry.2019.4709

Abstract: The modern concept of depression arose from earlier diagnostic formulations of melancholia over the hundred years from the 1780s to the 1880s. In this historical sketch, this evolution is traced from the writings of 12 authors outlining the central roles played by the concepts of faculty psychology and understandability. Five of the authors, writing from 1780 through the 1830s, including Cullen, Pinel, and Esquirol, defined melancholia as a disorder of intellect or judgment, a “partial insanity” often, but not always, associated with sadness. Two texts from the 1850s by Guislain, and Bucknill and Tuke were at the transition between paradigms. Both emphasized a neglected disorder—melancholia without delusions—arguing that it reflected a primary disorder of mood—not of intellect. In the final phase in the 1860s to 1880s, 5 authors (Griesinger, Sankey, Maudsley, Krafft-Ebing, and Kraepelin) all confronted the problem of the cause of delusional melancholia. Each author concluded that melancholia was a primary mood disorder and argued that the delusions emerged understandably from the abnormal mood. In this 100-year period, the explanation of delusional melancholia in faculty psychology terms reversed itself from an intellect to mood to a mood to intellect model. The great nosologists of the 19th century are often seen as creating our psychiatric disorders using a simple inductive process, clustering the symptoms, signs, and later the course of the patients. This history suggests 2 complexities to this narrative. First, in addition to bottom-up clinical studies, these nosologists were working top-down from theories of faculty psychology proposed by 18th century philosophers. Second, for patient groups experiencing disorders of multiple faculties, the nosologists used judgments about understandability to assign primary causal roles. This historical model suggests that the pathway from patient observation to the nosologic categories—the conceptual birth of our diagnostic categories—has been more complex than is often realized.

Introduction
Before the rise of modern psychiatry in the late 18th century, the concept of melancholia differed substantially from our modern view of depression,1-6 which did not emerge until the late 19th century.1,2,7,8 By examining key texts published from 1780 to 1880, I document the nature and timing of this shift through 3 phases. Two theories play important roles in this story: faculty psychology9-13 and understandability.13-16 Faculty psychology is defined as

The theory, in vogue particularly during the second half of the eighteenth and first half of the nineteenth centuries, that the mind is divided up into separate inherent powers or “faculties.”17(p253)

I focus on 2 of these inborn faculties, one predominant at the initiation of this story (intellect, understanding, or judgment), and the other whose rising influence I track across the 19th century: mood, affect, or moral (ie, psychological) sentiment.

Given the frequency of patients apparently experiencing disorders both of intellect and mood, the theory of faculty psychology posed a problem. To give a proper diagnosis, clinicians needed to distinguish between 3 hypotheses about such patients. Did they have 2 independent disorders, a primary disorder of intellect with a secondary mood disorder or a primary disorder of mood with a secondary disorder of intellect?13 A dominant approach to this problem, later popularized by Karl Jaspers,14,15 was that with careful observation and empathy, the clinician could discriminate between these hypotheses, for example, determining if a delusion (a disorder of intellect) could arise understandably from a disordered mood.

Phase 1: 1780-1830
In the first historical phase, all major authors emphasized that melancholia was primarily a disorder of intellect, often—but not always—accompanied by sadness.

I begin with the medical nosology of William Cullen (1710-1790), a physician and leading figure in the Scottish enlightenment. In his highly influential 1780 nosology,18,19 melancholia was placed within the class of neuroses (nervous disorders), and the order of vésanie (mental diseases/insanity) characterized as “a disorder of the functions of the judging faculty of the mind, without fever or sleepiness.”19 Melancholia was defined as “partial insanity without dyspepsia,” with the phrase “without dyspepsia” included to distinguish it from hypochondriasis. By partial insanity, Cullen meant that the delusions were limited to a single subject, leaving the affected individual with intact areas of intellectual functioning.

Phillipe Pinel (1745-1826),20,21 a major reformer and one of the founders of modern psychiatry, provided the following definition of melancholia in 1801:

Delirium (ie, delusions) exclusively upon one subject … free exercise in other respects of all the faculties of the understanding: in some cases, equanimity of disposition, or a state of unruffled satisfaction: in others, habitual depression and anxiety, and frequently a moroseness of character … and sometimes to an invincible disgust with life.21(p149)

Like Cullen,18,19 Pinel’s definition emphasized intellectual dysfunction (eg, partial insanity), but he added a range of associated mood states. Some of the states reflect depression but another described emotional equanimity.

In his 1804 treatise on madness and suicide,”22 the English physician William Rowley (1742-1806) gave a succinct definition of melancholia that agrees in essential points with his predecessors, with the disordered intellect here termed “alienation of the mind”:

Madness, or insanity, is an alienation of the mind, without fever. It is distinguished into two species; melancholy, or mania…. The former is known by sullenness, taciturnity, meditation, dreadful apprehensions, and despair.22(p1)

Rowley differs from his predecessors in associating melancholia only with the moods of sadness and anxiety.

In his 1817 monograph on melancholia,23 Maurice Roubaud-Luce’s description of melancholia resembled that of his French predecessor, Pinel,20,21 including its possible association with elevated mood states:

Melancholy is characterized by an exclusive and chronic delirium focused on a single object, or on a particular series of objects, with a free exercise of intellectual faculties on everything that is foreign to these objects. This condition is often accompanied by a deeply concentrated sadness, a state of dejection and stupor, and an ardent love of solitude. Sometimes also it excites, for no apparent reason, immoderate joy…. 23(p1)

Jean Esquirol (1772-1840), Pinel’s student and successor as leader of French psychiatry, coined the term lypemania as a synonym for melancholia.24,25 Like Rowley, in his 1838 textbook, he removed the association with mania-like partial insanities:

We consider it well defined, by saying that melancholy … or lypemania, is a cerebral malady, characterized by partial, chronic delirium, without fever, and sustained by a passion of a sad, debilitating or oppressive character.25(p203)

Phase 2: 1850-1860
In phase 2, the dominant view of melancholia as a primary disorder of intellect came under challenge.

Joseph Guislain (1789-1860), a Belgian alienist and director of the psychiatric hospital at Ghent, took a first step toward the modern view of depression. He described, in his 1852 text,26 6 elementary forms of mental maladies, one of which was mélancolie, defined as “mental pain—augmentation of sentiments of sadness.26(p94) He then described the relatively novel category of nondelusional melancholia, calling it

exclusively an exaggeration of affective feelings; it is a pathological emotion, a sadness, a grief, an anxiety, a fear, a fright, and nothing more. It is not a state which appreciably weakens conceptual faculties.26(p112)

He continues:

The description that the [prior] authors gave us of this disease [melancholy] leaves something to be desired; almost all spoke of delusional melancholy, and none, to my knowledge, describes melancholy in its state of greatest simplicity: there are melancholies without delusions … without noticeable disturbance of intelligence or ideas. Melancholy without delusion is the simplest form under which the suffering mode can occur; it is a state of sadness, dejection … without notable aberration of imagination, judgement or intelligence … a despair dominates him; he is absorbed into this painful feeling.26(p186)

In their influential 1858 textbook, John Bucknill (1817-1897) and Daniel Tuke (1827-1895) took a further step away from the view of melancholia as primarily a disorder of intellect. In the section on melancholia, written by Tuke, he begins with the quotation above from Esquirol25 to which he adds a critical comment (italics added):

“We consider it well-defined,” he observes “by saying that melancholia or lypemania, is cerebral malady, characterized by partial chronic delirium, without fever, and sustained by a passion of a sad, debilitating, or oppressive character.” A definition sufficiently accurate, if we except the “chronic delirium,” disorder of the intellect not being, as we shall presently see, an essential part of the disorder.27(p152)

Tuke argues that delusions have been incorrectly understood as the primary melancholic symptom. Following Guislain,26 Tuke operationalizes this change by defining a simple form of melancholia in which “there is here no disorder of the intellect, strictly speaking; no delusion or hallucination.27(p158) Bucknill and Tuke are then more explicit about their new conceptualization of melancholia: “it can be shown that the disorder at present under consideration, may coexist with a sound condition of the purely intellectual part of our mental constitution.27(p159)

Tuke provides his rationale for this conceptual shift in his earlier chapter on classification. After reviewing prior nosologic systems, he writes of the importance of faculty psychology in psychiatric nosology: “The writer thinks there is much to be said in favor of the attempt to classify the various forms of insanity, according to the mental functions affected.”27(p95) He then quotes his coauthor, “Dr Bucknill observes that insanity may be either intellectual, emotional, or volitional.”27(p95) We cannot, he argues, base our nosology on the “physiology of the organ of the mind,” because we do not know it. But, he continues, “in the absence of this knowledge it would seem reasonable to adapt them to the affected function.”27(p95) We could then, he concludes, “speak of disorders of the intellect, sentiment, etc. instead of basing our classification exclusively on prominent symptoms.”27(p95) He formalizes the conclusion:

In bringing the phenomena of diseased mind into relation with such classification, we should endeavor to refer every form of disease to that class or group of the mental faculties which the disease necessarily, though not exclusively, involves in its course.27(p98)

In his ideal nosology, idiocy, dementia, and monomania, which commonly manifests delusions and hallucinations, are disorders of the intellect while melancholia is considered a disorder of “moral sentiment,” that is, mood.

Phase 3: 1860-1883
Phase 3 continues the shift from the view that melancholia was predominantly a disorder of intellect to one of mood. But these authors also confronted the problem of delusional melancholia. If it too is primarily a disorder of mood, how can the emergence of delusions be explained? Their response to this question will incorporate the concept of understandability.

The first professor of psychiatry in Germany and a strong advocate for a brain-based psychiatry, Wilhelm Griesinger (1817-1868), early in his 1861 textbook,28,29 adopts a faculty psychological approach to psychiatric nosology in his chapter entitled “The Elementary Disorders in Mental Disease”:

In those cerebral affections which come under consideration as mental diseases, there are, as in all others, only three essentially distinct groups…. Thus, according to this threefold division, we have to consider successively each of the three leading groups of elementary disturbances—intellectual insanity, emotional insanity, and insanity of movement.29(p60)

Although like Guislain26 before him, Griesinger viewed melancholia as typically forming the first stage of a unitary psychosis: both of their descriptions are of relevance. Griesinger begins, “The fundamental affection in all these forms of disease consists in the morbid influence of a painful depressing negative affection—in a mentally painful state.”29(p209) That is, he clearly emphasized the affective nature of the disorder. He elaborates:

In many cases, after a period of longer or shorter duration, a state of vague mental and bodily discomfort … a state of mental pain becomes always more dominant and persistent…. This is the essential mental disorder in melancholia, and, so far as the patient himself is concerned, the mental pain consists in a profound feeling of ill-being, of inability to do anything, of suppression of the physical powers, of depression and sadness…. The patient can no longer rejoice in anything, not even the most pleasing.29(p223)

Earlier in the book, Griesinger sought to explain how disordered mood can produce delusions.

As to their contents, two leading differences are particularly to be observed in insane conceptions [one of which is] … somber, sad, and painful thoughts …. [which arise] from depressed states of the disposition, and gloomy ill-boding hallucinations, as language of abuse and mockery which the patient is always hearing, diabolical grimaces which he sees, etc. The false ideas and conclusions, which are attempts at explanation and vindications of the actual disposition in its effects, are spontaneously developed in the diseased mind according to the law of causality…. At first the delirious conceptions are fleeting … gradually, by continued repetition, they gain more body and form, repel opposing ideas … then they become constituent parts [of the “I”] … and the patient cannot divest himself of them.29(p71)

Early in his 1866 text, William Sankey (1813-1889), an asylum director and lecturer at University College London, outlined morbid psychiatric conditions of the intellect, emotions, and volition. He turned to discussing the development of melancholia:

The alterations in degree are such as an increase of grief, a depression of spirits going on to melancholy…. Such description of abnormal acts of mind belong to the emotions, and occur in the earlier stages, the later or more permanent alterations of kind may be manifested in the (a) intellect, (b) the disposition, (c) the manner, (d) temper, (e) habits, and (f) character of the individual.30(p25)

Therefore, primary alterations in emotions can lead to a range of developments in melancholia, including alterations in intellectual functioning including “in power of judgment, apprehension, imagination, argumentation, memory, or they may entertain distinct illusion [hallucination] or delusion.”30(p25) He captures this point in a case history of melancholia which he summarizes:

The progress of this case was therefore—simple depression, abstraction, forgetfulness, neglect of duties… religious fears, and morbid apprehensions and delusions… You see how closely nearly all these symptoms are connected with the emotions. Fear, apprehension, and dread are among the commonest phenomena.30(p30)

Early in his section on the varieties of insanity from his 1867 textbook,31 Henry Maudsley (1835-1918) adopted a faculty psychological orientation:

On a general survey of the symptoms of these varieties it is at once apparent that they fall into two well-marked groups one of these embracing all those cases in which the mode of feeling or the affective life is chiefly or solely perverted—in which the whole habit or manner of feeling, the mode of affection of the individual by events, is entirely changed; the other, those cases in which ideational or intellectual derangement predominates.31(p301)

He then outlines how the effects of the mood disorder spread through other faculties:

Consequently, when there is perversion of the affective life, there will be morbid feeling and morbid action; the patient's whole manner of feeling, the mode of his affection by events, is unnatural, and the springs of his action are disordered; and the intellect is unable to check or control the morbid manifestations.31(p302)

He later continues:

The different forms of affective insanity have not been properly recognised and exactly studied because they did not fall under the time-honoured divisions and the real manner of commencement of intellectual insanity in a disturbance of the affective life has frequently been overlooked.31(p321)

Maudsley then attacks the earlier views of melancholia—that the intellectual dysfunctions were primary and the mood disorder secondary (italics added):

It is necessary to guard against the mistake of supposing the delusion to be the cause of the passion, whether painful or gay …. Suddenly, it may be, an idea springs up in his mind that he is lost forever, or that he must commit suicide, or that he has committed murder and is about to be hanged; the vast and formless feeling of profound misery has taken form as a concrete idea —in other words, has become condensed into a definite delusion, this now being the expression of it. The delusion is not the cause of the feeling of misery, but is engendered of it, it is precipitated, as it were in a mind saturated with the feeling of inexpressible woe.31(p328)

Richard von Krafft-Ebing (1840-1902), among the most important late 19th century German-speaking neuropsychiatrists,32,33 wrote in his influential 1874 monograph on melancholia, “The basic phenomenon in melancholic insanity is simply mental depression, psychic pain in its elementary manifestation.”34(p1) By analogy with a peripheral neuralgia, melancholia transforms normal psychological experiences into anguish and sorrow. Affected individuals have repeated “painful distortions” of their experiences, “all his relations to the external world are different … he is unfeeling, homeless ... with unbearable despair.”34(p5)

In his section on melancholy with delusions and hallucinations, Krafft-Ebing writes

Let us look at the sources of these [symptoms]. Initially it is the altered sense of self of the patient, the consciousness of deep abasement … the fractured strength and ability to work, which require an explanation and, with advancing disturbance of consciousness, does not find this in the subjective aspect of the illness, but in the delusional changes of relationship to the external world, from which we are after all used to receiving the impulses for our feelings, ideas and ambitions. This formation of delusions is supported significantly by the deep disturbance of the perception of the world.34(p32)

He then gives examples of how delusions of poverty, persecution, and impending punishment can emerge “in a psychological manner … from elementary disturbances of mood”34(p34):

Thus, deep depression of the sense of self, and the consciousness of mental impotence and physical inability to work, lead to the delusion of no longer being able to earn enough, of being impoverished, of starvation.34(p33)

Mental dysesthesia thus causes hostile apperception of the external world, as presumed suspicious glances, scornful gestures, abusive speeches from the environment join, leading to persecutory delusions…. Precordial anxiety and expectations of humiliation lead to the delusion that an actual danger is threatening [where] … a prior harmless action which is not even a crime … is formed into an actual crime.34(p34)

Emil Kraepelin’s views of melancholia, unencumbered by his later development of the category of manic-depressive illness, can be found in the first edition of his textbook published in 1883. He saw this syndrome as arising from “psychological anguish” when “the feelings of dissatisfaction, anxiety and general misery gains such strength that it constantly dominates the mood.”35(p190) He describes the emergence of depressive delusions:

… in milder cases … there is insight into his own illness. As a rule, however, critical ability becomes overwhelmed by powerful mood fluctuations, and the pathological change is transferred to the external world. It does not merely seem to be so dismal and bleak, but really is so. A further progression … can then give rise to formal delusions and a systematic distortion of external experiences.35(p191)

The writings of Krafft-Ebing32,33 and Kraepelin35 reflect a culmination in the development of the modern concept of depression, an illness resulting primarily from a disorder of mood, which can manifest delusions that do not reflect an independent disorder of judgment or intellect but rather a rise, in an understandable manner, from the affective disturbance. We see a clear continuity from these authors to DSM-III36 in the signs and symptoms of what we now call major depression.7,8

Discussion
In this historical sketch, which could not examine all relevant authors or provide helpful background materials, I document that, during the rise of modern psychiatry in the late 18th and early 19th century, the concept of melancholia was closely wedded to earlier views that it was fundamentally a disorder of intellect—a partial insanity—often, but not always, accompanied by sadness. This concept was seen, with modest variation, in writings from 1780 through the 1830s from both England (Cullen18,19 and Rowley22) and France (Pinel,20,21 Roubaud-Luce,23 and Esquirol24).

In this narrative, the first movement away from this paradigm was by Guislain,26 writing just after the mid-19th century, who defined elementary melancholia as a disorder of mood and then focused on the neglected but illustrative category of nondelusional melancholia. Such patients demonstrated no abnormalities of intellect or judgment. This form of melancholia was, he suggested, a disorder primarily of mood.

In 1858, 2 British authors, Bucknill and Tuke,27 went further, declaring explicitly, in the language of faculty psychology, that a disorder of the intellect was not an essential part of melancholia. However, this assertion left a key problem. How could the common occurrence of melancholia with delusions be explained if melancholia was primarily a disorder of mood?

Our final 5 authors—Griesinger,28 Sankey,30 Maudsley,31 Krafft-Ebing,32,34 and Kraepelin35—each accepted the primacy of mood in the cause of melancholia and addressed the problem of the origin of melancholic delusions. Griesinger argued that “the false ideas …are attempts at explanation.”29(p71) Sankey noted “how closely nearly all these [psychotic] symptoms are connected with the emotions.”30(p30) Maudsley stated, “The vast and formless feeling of profound misery has taken form as a concrete [delusional] idea…. The delusion is not the cause of the feeling of misery but is engendered of it.”31(p328) Krafft-Ebing presented a compelling explanation of the psychological origin of melancholic delusions including the nature of “delusional changes of relationship to the external world”34(p32) and sketched how melancholic symptoms could lead, understandably, to delusions of poverty, persecution, or punishment. Kraepelin described how “critical ability becomes overwhelmed by powerful mood fluctuations.”35(p191)

This review provides the historical context for our modern concept of mood-congruent psychotic features, which was first introduced in the research diagnostic criteria as “typical depressive delusions such as delusions of guilt, sin, poverty, nihilism, or self-deprecation,”37(p16) and then incorporated with modest changes in DSM-III36 and all subsequent DSM editions. Echoing the writings of authors reviewed herein, this list reflects delusions whose content can be understandably derived from the primary mood disturbance in major depression.

These historical observations have important implications for how we understand the nature of our psychiatric categories. A prominent narrative is that the great psychiatric nosologists of the 19th century acted as simple inductivists, seeing large numbers of patients with psychiatric disorders and, based initially on symptoms and signs and later also on course of illness, then sorting them into diagnostic categories. This inquiry suggests a more complex process.

First, as illustrated herein and described elsewhere,13,38,39 across Europe during the 19th century, systems of faculty psychology, innate functions of the human mind, were propounded by a range of philosophers, including Kant, Reid, and Stewart.10,38 These faculties provided influential a priori categories for psychiatric nosologists. As articulated explicitly by Tuke, absent a knowledge of pathophysiology, diagnostic categories should at least be based on the “affected function” (eg, “disorders of the intellect, sentiment, etc”27(p95)) rather than exclusively on symptoms.

Second, given the adoption of faculty psychology, nosologists had to confront the problem of the classification of patients apparently experiencing disorders of 2 faculties, such as individuals with delusional melancholia. Did these patients have 2 disorders or only 1 and, if so, which one? The creation of our modern concept of depression arose from an argument about the primacy of disordered intellect vs disordered mood in explaining the cause of delusional melancholia. The early model, consistent with the then dominant intellectualist view of insanity,40,41 assumed that disordered judgment was the essence of melancholia, which was first and foremost a disorder of intellect. Over the 19th century, this opinion was reversed. By the 1870s, it became widely accepted that melancholia was primarily a mood disorder. The argument that fueled that major diagnostic change appealed to understandability—that clinicians could empathically grasp how disordered mood could lead to particular kinds of delusions.

Rather than naive inductivism, a more realistic model for the development of psychiatric nosology in the 19th century would reflect a mixture of bottom-up and top-down processes. Psychiatric neuroscientists and geneticists working today are not studying the biological substrate of illnesses in patients classified from raw clinical experience. Rather, our diagnostic categories reflect clinical observations translated through mentalistic constructs from philosophers who divided the major functions of the human mind into faculties. An obvious question then is whether these faculties have a coherent biological substrate. In an 1857 essay, Henry Monro expressed concerns exactly on this point: Can we relate the metaphysical structure of mental faculties to brain structures? He wrote

Physiology points further than to the general truth that brain as a whole is the instrument of the mind as a whole, and gives us good reason to believe that the great faculties, the emotions, the sensations, and the intelligence, have distinguishable ganglia, sensoria, or spheres of action.42(p196)

The success of our efforts at understanding the biologic characteristics of major psychiatric disorders might therefore depend, in part, on how successfully the faculty psychology of 18th century philosophers reflected brain structure and function. Furthermore, our nosologic categories are influenced by empathy-based insights into the nature of psychological causation. When can a delusion be understood to derive from disordered mood rather than from a primary disorder of intellect? The degree to which these empathy-based mentalistic processes translate into a discernable neurobiology is not well known.

This history suggests that the path from patient observation to our nosologic categories and from there, hopefully, to a detectable pathophysiologic nature is more complex than is commonly realized.

Blatantly dehumanizing representations of Arabs seem as prevalent among individuals exhibiting low levels of explicit dehumanization (liberals) as among those of high levels of explicit dehumanization (conservatives)

Petsko, Christopher D., Ryan Lei, Jonas R. Kunst, Emile Bruneau, and Nour Kteily. 2020. “Blatant Dehumanization in the Mind's Eye: Prevalent Even Among Those Who Explicitly Reject It?.” PsyArXiv. August 5. doi:10.31234/osf.io/g7w4b

Abstract: Research suggests that some people, particularly those on the political right, have a tendency to blatantly dehumanize low-status groups. However, these findings have largely relied on self-report measures, which are notoriously subject to social desirability concerns. To better understand just how widely blatant forms of intergroup dehumanization might extend, the present paper leverages an unobtrusive, data-driven perceptual task to examine how U.S. respondents mentally represent ‘Americans’ vs. ‘Arabs’ (a low-status group in the U.S. that is often explicitly targeted with blatant dehumanization). Data from two reverse-correlation experiments (original N = 108; pre-registered replication N = 336) and seven rating studies (N = 2,301) suggest that U.S. respondents’ mental representations of Arabs are significantly more dehumanizing than their representations of Americans. Furthermore, analyses indicate that this phenomenon is not reducible to a general tendency for our sample to mentally represent Arabs more negatively than Americans. Finally, these findings reveal that blatantly dehumanizing representations of Arabs can be just as prevalent among individuals exhibiting low levels of explicit dehumanization (e.g., liberals) as among individuals exhibiting high levels of explicit dehumanization (e.g., conservatives)—a phenomenon into which exploratory analyses suggest liberals may have only limited awareness. Taken together, these results suggest that blatant dehumanization may be more widespread than previously recognized, and that it can persist even in the minds of those who explicitly reject it.




Does merely referencing that an object or entity has changed affect people’s attitudes and intentions toward it? It boosts curiosity and promotes persuasion

Change Appeals: How Referencing Change Boosts Curiosity and Promotes Persuasion. Daniella Kupor et al. Personality and Social Psychology Bulletin, August 5, 2020. https://doi.org/10.1177/0146167220941294

Abstract: Does merely referencing that an object or entity has changed affect people’s attitudes and intentions toward it? This research investigates the possibility that change references spark curiosity and information seeking, which can have a positive or negative effect on people’s evaluations of a target stimulus, depending on the information environment. Seven experiments reveal that referencing that an object or entity has changed decreases perceptions of its longevity, but also sparks curiosity about it—a desire to learn more. This curiosity motivates people to seek information about the object or entity, which can enhance or depress their evaluations depending on whether that information search leads to favorable or unfavorable information. When further information is unavailable, change references appear to have a negative impact on people’s evaluations, consistent with well-established longevity biases. This research suggests that change references have an important and generalizable impact on persuasive outcomes and pinpoints the conditions surrounding and processes driving this effect.

Keywords: information seeking, change, curiosity



Wednesday, August 5, 2020

Current anthropological hypotheses do not sufficiently explain why habitual concealment of mating evolved in humans but is only seldom exhibited by other social species

Why do human and non-human species conceal mating? The cooperation maintenance hypothesis. Yitzchak Ben Mocha. Proceedings of the Royal Society B: Biological Sciences, Volume 287, Issue 1932, August 5 2020. https://doi.org/10.1098/rspb.2020.1330

Abstract: Despite considerable cultural differences, a striking uniformity is argued to exist in human preferences for concealing sexual intercourse from the sensory perception of conspecifics. However, no systematic accounts support this claim, with only limited attempts to understand the selective pressures acting on the evolution of this preference. Here, I combine cross-cultural and cross-species comparative approaches to investigate these topics. First, an analysis of more than 4572 ethnographies from 249 cultures presents systematic evidence that the preference to conceal mating is widespread across cultures. Second, I argue that current anthropological hypotheses do not sufficiently explain why habitual concealment of mating evolved in humans but is only seldom exhibited by other social species. Third, I introduce the cooperation maintenance hypothesis, which postulates that humans, and a specific category of non-human species, conceal matings to prevent sexual arousal in witnesses (proximate explanation). This allows them to simultaneously maintain mating control over their partner(s) and cooperation with group members who are prevented from mating (ultimate explanations). I conclude by presenting a comparative framework and predictions to be tested across species and human cultures.


3. Hypotheses on the function of concealed mating in humans and their limitations

Widespread human behaviours are strong candidates for evolutionary adaptations. Their functions should therefore also be studied from an evolutionary perspective [5,19]. I thus now turn from an ethnographic survey on the prevalence of concealed mating to an evolutionarily based investigation of its function.

To date, only brief explanations have been suggested for the function of concealed mating (e.g. a few sentences or a footnote). To the best of my knowledge, the first explanation was proposed in 1930 by Malinowski, who argued that public mating ‘excites jealousy. Hence to make love or to eat in public is to invite rivals to seize that which is being enjoyed' ([6], p. 179). Half a century later, Symons repeated a similar argument: ‘Ultimately, this [concealed mating] probably is the outcome of reproductive competition. Where food is scarce, and the sight of people eating produces envy in the unfed, eating is often conducted in private. While there are many societies in which everyone has enough to eat, there are no societies in which everyone can copulate with all the partners he or she desires […] The seeking of privacy for sex probably has been uniformly adaptive and hence is virtually universal among humans' ([2], p. 67).

Building on this interaction between jealousy and reproductive competition, Friedl posited the costly consequence of reproductive competition: ‘the value of hidden sex [is] to protect [the copulating pair] and the social group from the dangers of jealousy caused by competition […] for mates, [as] a degree of social harmony is a prerequisite for an individual animal's reproductive success' ([3], p. 838). Similarly, van Schaik recently hypothesized that ‘the benefit for the man is that it prevents overt contest competition for access to potentially fertile mates, which would threaten male–male cooperation' ([11], p. 184).

These explanations share the view that avoiding overt reproductive competition is the main function of concealed mating in humans, while differing in the importance ascribed to cooperation. Malinowski and Symons neglect the importance of cooperation altogether, Friedl invokes the cost of reproductive competition on ‘social harmony', and van Schaik points out the importance of male–male cooperation. However, if these hypotheses were true, I would expect to find habitual concealment of matings in many other social species. Specifically, I would expect to find concealed matings in our phylogenetically closest living relatives, the social non-human great apes (bonobos Pan paniscus, chimpanzees Pan troglodytes and mountain gorillas Gorilla beringei beringei). In these species, within-group reproductive competition is common (electronic supplementary material, appendix S7), while social cohesion is crucial for between-group competition [20–22] and, at least among chimpanzees, male–male cooperation is vital [22]. Nevertheless, dominant individuals from these species seldom conceal matings from the view of conspecifics (electronic supplementary material, appendix S7; see §4d(iv) and §5 for explanations for occasional concealment in these species).

In conclusion, although the selective pressures proposed by current explanations may have played a role in the evolution of concealed mating, in my opinion, these explanations do not sufficiently explain why habitual concealment evolved in humans but is rarely exhibited in other social great apes. I propose that explaining the currently known taxonomic distribution of concealed mating should be the first touchstone for any hypothesis aiming to explain the function of concealed mating in humans.

4. The cooperation maintenance hypothesis

In this section, I discuss the cooperation maintenance hypothesis (hereafter ‘CMH’). I first review the phenomenon of concealed mating in non-human species, while emphasizing the Arabian babbler (Turdoides squamiceps), for which this hypothesis was originally proposed [23]. Second, I develop a cross-species and cross-cultural account of the hypothesis. Third, I apply the CMH to explain the human case. Fourth, I present predictions to test the CMH across species and human cultures.

(a) Non-human species
In a wide range of species, subordinate animals conceal matings to avoid interference by more dominant group members. Dominant individuals, by contrast, often mate in full view of group members and seldom actively conceal matings (see electronic supplementary material, appendix S7 for review of 34 species and §4d(iv) and §5 for potential explanations). To my knowledge, habitual concealment of matings by individuals that are not subject to physical interruption by conspecifics has so far been documented in two species only: humans and Arabian babblers.

Arabian babblers are cooperative breeding birds living in the Middle East [24]. They live in stable, territorial groups (2–22 individuals) that include all combinations of age, sex and kin relations [24]. During days in which the alpha female ovulates, she is mate-guarded by the alpha male, who may use dominance displays when other males interact with her [25]. Consequently, the dominant pair produces 95% of the offspring [26]. Nonetheless, all group members participate in rearing offspring (e.g. transferring them between shelters [27]) and other cooperative interactions [28]. Helpers have therefore a significant effect on offspring survival [29].

Arabian babblers use discreet communication to initiate copulation [25]. Then, pairs sneak away and only mate in locations and/or times in which they are hidden from view of other group members [23]. Subordinate Arabian babblers are likely to conceal their matings since they risk attack if discovered by more dominant group members [23,25]. A subordinate bird, however, would not attack the dominant pair if it happened to interrupt the privacy of mating [23,25]. After presenting evidence against common explanations for inconspicuous matings in non-human species (see §5), Ben Mocha et al. [23] proposed that dominant Arabian babblers conceal visual stimuli of mating to (i) avoid triggering extra-pair matings by helpers and (ii) maintain alloparental care (by avoiding conflicts that would increase the probability of helpers challenging the alpha position or dispersing).

(b) The cooperation maintenance hypothesis: cross-species and cross-cultural account
The CMH is based on the following argument:

If:

(i)
Sensory stimuli of mating between conspecifics evokes sexual arousal and trigger mating behaviour in witnesses (hereafter, the sexual arousal premise).

(ii)
X (a male and/or a female) tries to control mating access to his/her partner(s) (hereafter, the mating control premise).

(iii)
X depends on cooperation with group members that he/she prevents from mating with his/her partner(s) (hereafter, the cooperation dependency premise).

Then:

Public mating between X and his/her partner will evoke sexual arousal in group members (males and/or females). This, in turn, will increase the likelihood that aroused witnesses will attempt to initiate mating with X's partner when possible (the sexual arousal premise). These attempts will violate X's efforts to control mating access to his/her partner (the mating control premise) and will trigger social conflicts that will harm the cooperation between X and his/her group members (the cooperation dependency premise; figure 1).

[Figure 1. The predicted consequences of concealed and public mating in social systems where an individual tries to control mating access to all or specific partner(s), while also dependent on cooperation with group members that are prevented from mating with his/her partner(s). (Online version in colour.)]

By contrast, sensory concealment of X's mating with his/her partner will not evoke sexual arousal in group members. Hence, the act of mating will not induce extra-pair mating with X's partner and will not affect X's cooperation with other group members (figure 1). I therefore suggest that concealed mating by individuals whose mating is not subject to physical interruption by conspecifics is a relatively non-costly strategy for avoiding unnecessary sexual arousal in group members (proximate explanation). At the ultimate level, concealed mating allows an individual to maintain two needs that would otherwise conflict: mating control over his/her partner(s) and cooperation with those group members that are prevented from mating with these partner(s).

Thus, the CMH elaborates factors that were previously proposed to select for concealed mating—jealousy [2,6], reproductive competition [2,3,11] and social harmony/male–male cooperation [3,11]—and combines them as necessary premises of a coherent argument. According to the CMH, explanations that rely solely on avoiding reproductive competition [2,6] are not sufficient, since the question of concealed mating is only applied to individuals who do not expect interference from conspecifics (e.g. dominant individuals). In addition, in social systems without cooperation, dominant animals settle conflicts with aggression and often mate in public (e.g. Rocky Mountain bighorn sheep Ovis Canadensis [30]). But where competitors also cooperate, aggression may eliminate future cooperation (for ethnographic examples in Yanomamö see [31]). The CMH differs from previous explanations by requiring both a specific form of reproductive competition (i.e. attempting to prevent group members from mating with one's partner) and reliance on cooperation between group members. It thereby highlights the need to manoeuvre between these conflicting motives as the crucial selective pressure.

The CMH further stands up to evolutionary critiques that previous explanations failed to address. Namely, it can explain why dominant individuals of non-human great apes seldom conceal mating: because they rarely monopolize a specific partner (bonobos and chimpanzees use other forms of reproductive competition, e.g. sperm competition [32]; electronic supplementary material, appendix S7]) or they do not depend on cooperation with subordinate group members (mountain gorillas; electronic supplementary material, appendix S7)—at least not to the same extent as humans and Arabian babblers (but see §4d(iv)).

(c) Explaining the human case
In the following, I discuss the evidence that supports the three premises of the CMH in humans.

(i) Sensory stimuli of mating between conspecifics evoke sexual arousal and trigger mating behaviour in witnesses
Visual [33] and auditory [34] stimuli of mating activate the reward system in the human brain and trigger mating behaviour in males and females via mirror neurons. For ethnographic examples, see the Goajiro [35] and Lesu [16].

Knowing that a desired group member has a legitimate mating tie with another person may also trigger jealousy (see the Muria for ethnographic examples [18]). Yet, the sensory stimulus of mating is another powerful trigger of sexual arousal that can be prevented by sensory concealment. The benefits of sensory concealment therefore do not rely on individuals being ignorant of the existence of mating ties between group members.

(ii) X (a male and/or a female) tries to control mating access to his/her partner(s)
Various scholars have claimed that in virtually all cultures, husbands and/or wives try to control mating access to their spouse(s)—at least to a certain degree [1,2,9,36]. Three clarifications should be made regarding this claim. First, mating control should not be confused with monogamy. For instance, a man/woman may marry several wives/husbands and forbid them to have extramarital sex. Second, it has been argued that even in cultures where some extramarital sex is allowed (e.g. in cultures with ‘shared paternity'), husbands and/or wives are still entitled to restrict the trysts of their spouse(s) to specific individuals and/or limit extramarital sex to the greatest possible extent [9]. Third, this premise requires an attempt, not a success, to control mating access to X's spouse(s). As adultery is evident across human societies [10], this emphasizes the importance of behavioural strategies to reduce its occurrence.

Although it has been claimed repeatedly that restrictive sexual norms are virtually universal, there is a dearth of supporting evidence (but see [1,9]). Hence, I analysed whether social norms in this study's dataset entitle husbands and/or wives to at least some control over mating access to their spouse(s), or, in contrast, if both spouses are allowed to have unrestricted extramarital sex (see electronic supplementary material, appendix S1 for methodology). I found social norms that entitle mating control over spouse(s) in 100% of cultures for which data were available (survey dataset: n = 210; SCCS/EA dataset: n = 145; see electronic supplementary material, appendix S8 for full account). Cultures had diverse norms of sexual control; for instance, norms that forbid both spouses to have extramarital sex (e.g. orthodox Jews [37]); cultures where wives are required to stay faithful to their husbands, but husbands are allowed to have extramarital sex (e.g. Malekula [38]); and cultures where husbands and/or wives are allowed to have extramarital sex, but only with specific partners (e.g. Huaorani [39]). I found no culture in which social norms entitle both husbands and wives unrestricted freedom to engage in extramarital sex. These norms suggest that in virtually all human societies, group members are prevented (sometimes or always) from mating with spouses of others.

(iii) X depends on cooperation with group members that he/she prevents from mating with his/her partner(s)
Humans depend on cooperation with group members in various aspects, such as hunting and between-group competition (e.g. [31]). Furthermore, an individual's fitness critically depends on systematic alloparental care from kin and non-kin [40]. For example, the survival of parents and offspring in hunter–gatherers Hiwi (Venezuela) and Ache (Paraguay) depends on food obtained by young, unrelated males [41]; infants of the Aka people in central  Africa are carried by kin and non-kin helpers for roughly 30% of the time [42]. Humans are thus considered a communal, and even cooperatively breeding, species [40].

(iv) Summary
In conclusion, visual and audile stimuli of human mating trigger sexual arousal and sexual behaviour in both male and female observers [33,34]; across cultures, husbands and/or wives attempt to control mating access to their spouse(s) (electronic supplementary material, Appendix S8, [9]); humans live in social systems where fitness crucially depends on cooperation between group members [40,41]. I therefore suggest that the habitual concealment of legitimate mating in humans is a relatively non-costly behavioural strategy to prevent unnecessary sexual arousal in group members (proximate explanation). This simultaneously maintains control over mating access to their spouse(s) as well as cooperation with group members that are prevented from mating with their spouse(s) (ultimate explanations).

Undergraduates enrolled in introductory psychology courses: Certain misconceptions about mental illness & treatments are widely held; tend to possess weaker critical thinking skills & accept more some paranormal claims

Basterfield, C., Lilienfeld, S. O., Cautin, R. L., & Jordan, D. (2020). Mental illness misconceptions among undergraduates: Prevalence, correlates, and instructional implications. Scholarship of Teaching and Learning in Psychology, Aug 2020. https://doi.org/10.1037/stl0000221

Abstract: Although several published studies have examined students’ misconceptions about psychology in general, only 1 study has focused exclusively on misconceptions about mental illness, and that study examined only 5 such misconceptions. To overcome this gap in our knowledge and to devise effective teaching strategies to disabuse college students of false information, an up-to-date survey of current misconceptions and their correlates among students is necessary. In this study, 375 undergraduates enrolled in introductory psychology courses completed an abnormal psychology misconceptions questionnaire, as well as measures assessing critical thinking, attitudes toward science, beliefs in paranormal phenomena, and vocational interests. Results revealed that certain misconceptions about mental illness and its treatment are widely held, and that compared with other students, students who endorse mental illness misconceptions tend to possess weaker critical thinking skills, are more inclined to accept paranormal claims, and are less likely to endorse scientific and behavioral views of psychology. Given the prevalence of abnormal psychology misconceptions among introductory students, we provisionally recommend assessing mental illness misconceptions early in an introductory course and utilizing empirically supported refutational methods to reduce student levels of mental illness misconceptions.




The intertemporal cortex of untrained primates can serve as a precursor of orthographic processing; the acquisition of reading in humans seems to rely on the recycling of a brain network evolved for other visual functions

The inferior temporal cortex is a potential cortical precursor of orthographic processing in untrained monkeys. Rishi Rajalingham, Kohitij Kar, Sachi Sanghavi, Stanislas Dehaene & James J. DiCarlo. Nature Communications volume 11, Article number: 3886. Aug 4 2020. https://www.nature.com/articles/s41467-020-17714-3

Abstract: The ability to recognize written letter strings is foundational to human reading, but the underlying neuronal mechanisms remain largely unknown. Recent behavioral research in baboons suggests that non-human primates may provide an opportunity to investigate this question. We recorded the activity of hundreds of neurons in V4 and the inferior temporal cortex (IT) while naïve macaque monkeys passively viewed images of letters, English words and non-word strings, and tested the capacity of those neuronal representations to support a battery of orthographic processing tasks. We found that simple linear read-outs of IT (but not V4) population responses achieved high performance on all tested tasks, even matching the performance and error patterns of baboons on word classification. These results show that the IT cortex of untrained primates can serve as a precursor of orthographic processing, suggesting that the acquisition of reading in humans relies on the recycling of a brain network evolved for other visual functions.


Discussion
A key goal of human cognitive neuroscience is to understand how the human brain supports the ability to learn to recognize written letters and words. This question has been investigated for several decades using human neuroimaging techniques, yielding putative brain regions that may uniquely underlie orthographic abilities7,8,9. In the work presented here, we sought to investigate this issue in the primate ventral visual stream of naïve rhesus macaque monkeys. Non-human primates such as rhesus macaque monkeys have been essential to study the neuronal mechanisms underlying human visual processing, especially in the domain of object recognition where monkeys and humans exhibit remarkably similar behavior and underlying brain mechanisms, both neuroanatomical and functional13,14,15,16,39,40. Given this strong homology, and the relative recency of reading abilities in the human species, we reasoned that the high-level visual representations in the primate ventral visual stream could serve as a precursor that is recycled by developmental experience for human orthographic processing abilities. In other words, we hypothesized that the neural representations that directly underlie human orthographic processing abilities are strongly constrained by the prior evolution of the primate visual cortex, such that representations present in naïve, illiterate, non-human primates could be minimally adapted to support orthographic processing. Here, we observed that orthographic information was explicitly encoded in sampled populations of spatially distributed IT neurons in naïve, illiterate, non-human primates. Our results are consistent with the hypothesis that the population of IT neurons in each subject forms an explicit (i.e., linearly separable, as per ref. 21) representation of orthographic objects, and could serve as a common substrate for learning many visual discrimination tasks, including ones in the domain of orthographic processing.

We tested a battery of 30 orthographic tests, focusing on a word classification task (separating English words from pseudowords). This task is referred to as “lexical decision” when tested on literate subjects recognizing previously learned words (i.e., when referencing a learned lexicon). For nonliterate subjects (e.g., baboons or untrained IT decoders), word classification is the ability to identify orthographic features that distinguish between words and pseudowords and generalize to novel strings. This generalization must rely on specific visual features whose distribution differs between words and pseudowords; previous work suggests that such features may correspond to specific bigrams17, position-specific letter combinations41, or distributed visual features42. While this battery of tasks is not an exhaustive characterization of orthographic processing, we found that it has the power to distinguish between alternative hypotheses. Indeed, these tasks could not be accurately performed by linear readout decoders of the predominant input visual representation to IT (area V4) or by approximations of lower levels of the ventral visual stream, unlike many other coarse discrimination tasks (e.g., contrasting orthographic and nonorthographic stimuli). We note that the successful classifications from IT-based decoders do not necessarily imply that the brain exclusively uses IT or the same coding schemes and algorithms that we have used for decoding. Rather, the existence of this sufficient code in untrained and illiterate non-human primates suggests that the primate ventral visual stream could be minimally adapted through experience-dependent plasticity to support orthographic processing behaviors.

These results are consistent with a variant of the “neuronal recycling” theory, which posits that the features that support visual object recognition may have been coopted for written word recognition5,6,24. Specifically, this variant of the theory is that humans have inherited a pre-existing brain system (here, the ventral visual stream) from recent evolutionary ancestors, and they either inherited or evolved learning mechanisms that enable individuals to adapt the outputs of that system during their lifespan for word recognition and other core aspects of orthographic processing. Consistent with this, our results suggest that prereading children likely have a neural population representation that can readily be reused to learn invariant word recognition. Relatedly, it has been previously proposed that the initial properties of this system may explain the child’s early competence and errors in letter recognition, e.g., explaining why children tend to make left-right inversion errors by the finding that IT neurons tend to respond similarly to horizontal mirror images of objects36,37,43. Consistent with this, we here found that the representation of IT-based decoders exhibited a similar signature of left-right mirror symmetry. According to this proposal, this neural representation would become progressively shaped to support written word recognition in a specific script over the course of reading acquisition, and may also explain why all human writing systems throughout the world rely on a universal repertoire of basic shapes24. As shown in the present work, those visual features are already well encoded in the ventral visual pathway of illiterate primates, and may bias cultural evolution by determining which scripts are more easily recognizable and learnable.

A similar “neuronal recycling hypothesis” has been proposed for the number system: all primates may have inherited a pre-existing brain system (in the intraparietal sulcus) in which approximate number and other quantitative information is well encoded44,45. It has been suggested that these existing representations of numerosity may be adapted to support exact, symbolic arithmetic, and may bias the cultural evolution of numerical symbols6,46. Likewise, such representations have been found to spontaneously emerge in neural network models optimized for other visual functions47. Critically, the term “recycling,” in the narrow sense in which it was introduced, refers to such adaptations of neural mechanisms evolved for evolutionary older functions to support newer cultural functions, where the original function is not entirely lost and the underlying neural functionality constrains what the brain can most easily learn. It remains to be seen whether all instances of developmental plasticity meet this definition, or whether learning may also simply replace unused functions without recycling them48.

In addition to testing a prediction of this neuronal recycling hypothesis, we also explored the question of how orthographic stimuli are encoded in IT neurons. Decades of research has shown that IT neurons exhibit selectivity for complex visual features with remarkable tolerance to changes in viewing conditions (e.g., position, scale, and pose)19,22,23. More recent work demonstrates that the encoding properties of IT neurons, in both humans and monkeys, is best explained by the distributed complex invariant visual features of hierarchical convolutional neural network models30,49,50. Consistent with this prior work, we here found that the firing rate responses of individual neural sites in macaque IT was modulated by, but did not exhibit strong selectivity to orthographic properties, such as letters and letter positions. In other words, we did not observe precise tuning as postulated by “letter detector” neurons, but instead coarse tuning for both letter identity and position. It is possible that, over the course of learning to read, experience-dependent plasticity could fine-tune the representation of IT to reflect the statistics of printed words (e.g., single-neuron tuning for individual letters or bigrams). Moreover, such experience could alter the topographic organization to exhibit millimeter-scale spatial clusters that preferentially respond to orthographic stimuli, as have been shown in juvenile animals in the context of symbol and face recognition behaviors18,51. Together, such putative representational and topographic changes could induce a reorientation of cortical maps towards letters at the expense of other visual object categories, eventually resulting in the specialization observed in the human visual word form area (VWFA). However, our results demonstrate that, even prior to such putative changes, the initial state of IT in untrained monkeys has the capacity to support many learned orthographic discriminations.

In summary, we found that the neural population representation in IT cortex in untrained macaque monkeys is largely able, with some supervised instruction, to extract explicit representations of written letters and words. This did not have to be so—the visual representations that underlie orthographic processing could instead be largely determined over postnatal development by the experience of learning to read. In that case, the IT representation measured in untrained monkeys (or even in illiterate humans) would likely not exhibit the ability to act as a precursor of orthographic processing. Likewise, orthographic processing abilities could have been critically dependent on other brain regions, such as speech and linguistic representations, or putative flexible domain-general learning systems, that evolved well after the evolutionary divergence of humans and Old-World monkeys. Instead, we here report evidence for a precursor of orthographic processing in untrained monkeys. This finding is consistent with the hypothesis that learning rests on pre-existing neural representations which it only partially reshapes.