Review evidence challenging the hypothesis that memories are processed/consolidated in sleep; the brain is in an unconscious state in sleep, akin to general anesthesia, & is incapable of meaningful cognitive processing

No cognitive processing in the unconscious, Anesthetic‐Like, state of sleep. Robert P. Vertes,  Stephanie B. Linley. Journal of Comparative Neurology, May 30 2020. https://doi.org/10.1002/cne.24963

Abstract: We review evidence challenging the hypothesis that memories are processed or consolidated in sleep. We argue that the brain is in an unconscious state in sleep, akin to general anesthesia, and hence is incapable of meaningful cognitive processing – the sole purview of waking consciousness. At minimum, the encoding of memories in sleep would require that waking events are faithfully transferred to and reproduced in sleep. Remarkably, however, this has never been demonstrated, as waking experiences are never truly replicated in sleep but rather appear in very altered or distorted forms. General anesthetics (GAs) exert their effects through endogenous sleep‐wake control systems and accordingly GAs and sleep share several common features: sensory blockade, immobility, amnesia and lack of awareness (unconsciousness). The loss of consciousness in non‐REM (NREM) sleep or to GAs is characterized by: (1) delta oscillations throughout the cortex; (2) marked reductions in neural activity (from waking) over widespread regions of the cortex, most pronounced in frontal and parietal cortices; and (3) a significant disruption of the functional connectivity of thalamocortical and corticocortical networks, particularly those involved in “higher order” cognitive functions. Several (experimental) reports in animals and humans have shown that disrupting the activity of the cortex, particularly the orbitofrontal cortex, severely impairs higher order cognitive and executive functions. The profound and widespread deactivation of the cortex in the unconscious states of NREM sleep or GA would be expected to produce an equivalent, or undoubtedly a much greater, disruptive effect on mnemonic and cognitive functions. In conclusion, we contend that the unconscious, severely altered state of the brain in NREM sleep would negate any possibility of cognitive processing in NREM sleep.

Infidelity, chastity/purity, and long-term mating success increase women’s status more than men’s; promiscuity lowers the status of both sexes, but lowers it more dramatically for women than for men

Buss, D. M., Durkee, P. K., Shackelford, T. K., Bowdle, B. F., Schmitt, D. P., Brase, G. L., Choe, J. C., & Trofimova, I. (2020). Human status criteria: Sex differences and similarities across 14 nations. Journal of Personality and Social Psychology, May 2020. https://doi.org/10.1037/pspa0000206

Abstract: Social status is a central and universal feature of our highly social species. Reproductively relevant resources, including food, territory, mating opportunities, powerful coalitional alliances, and group-provided health care, flow to those high in status and trickle only slowly to those low in status. Despite its importance and centrality to human social group living, the scientific understanding of status contains a large gap in knowledge—the precise criteria by which individuals are accorded high or low status in the eyes of their group members. It is not known whether there exist universal status criteria, nor the degree to which status criteria vary across cultures. Also unknown is whether status criteria are sex differentiated, and the degree of cross-cultural variability and consistency of sex-differentiated status criteria. The current article investigates status criteria across 14 countries (N = 2,751). Results provide the first systematic documentation of potentially universal and sex-differentiated status criteria. Discussion outlines important next steps in understanding the psychology of status.

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[T]he content-level analyses further confirmed that all components of attractiveness (i.e., hygiene, appearance) and domestic skills (i.e., cooking ability, parenting skill, and cleanliness) are more central to women’s status than men’s status across the countries sampled. Sex differences in the effects of women’s sexual strategy on status are especially clear at the content level. Infidelity, chastity/purity, and long-term mating success increase women’s status more than men’s. Sexual promiscuity lowers the status of both sexes, but lowers it more dramatically for women than for men (see Figure 11).

How Financial News Affects Prosocial Behavior

Kang, Polly and Daniels, David and Schweitzer, Maurice E., How Financial News Affects Prosocial Behavior (April 22, 2020). SSRN: https://ssrn.com/abstract=3583884

Abstract: A fundamental puzzle in the social and natural sciences is why humans, in contrast to other animals, routinely help strangers at substantial personal cost. Scholars assert that humans’ hyper-prosociality can be explained by the “warm glow” prosocial actors derive from helping others, and predict that people with greater resources will help more. We challenge these assertions. Many prosocial behaviors involving feedback, like volunteering, are actually warm glow gambles: first, prosocial actors invest affective resources trying to help others; then, positive feedback (e.g., feedback suggesting “success”) boosts affective resources but negative feedback (e.g., feedback suggesting “failure”) diminishes affective resources. We theorize that either negative affect shocks (by depleting affective resources) or positive affect shocks (by triggering risk aversion) can decrease people’s likelihood of taking warm glow gambles. We test this by studying the influence of a complex human institution, the stock market, which broadcasts negative affect shocks when the market falls (suggesting bad financial news) and positive affect shocks when it rises (suggesting good financial news). Analyzing a unique, massive five-year dataset of nearly 3 million text messages sent by volunteer crisis counselors, we show that significantly fewer people volunteer when stock returns are either extremely negative or extremely positive; prosocial behavior peaks on “normal” days when returns approach zero. Further supporting our theory, these effects are moderated by the level of positive affect in volunteers’ geographical areas. Our findings contradict existing theories and lay beliefs. Ironically, an institution designed for economic efficiency broadcasts signals that profoundly influence humans’ hyper-prosocial behavior.

Keywords: prosocial behavior; warm glow; prospect theory; financial markets

France: Ideological extremity is associated with a reduced adherence to public health recommendations; at the same time, compliance increases as one moves from Left to Right

Sociodemographic and Psychological Correlates of Compliance with the COVID-19 Public Health Measures in France. Sylvain Brouard, Pavlos Vasilopoulos & Michael Becher. Canadian Journal of Political Science, April 23 2020. : https://doi.org/10.1017/S0008423920000335

Extract: The COVID-19 disease was first identified in Wuhan, China, in December 2019, having since spread rapidly across the world. The infection and mortality rates of the disease have forced governments to implement a wave of public health measures. Depending on the context, these range from the implementation of simple hygienic rules to measures such as social distancing or lockdowns that cause major disruptions in citizens’ daily lives. The success of these crucial public health measures rests on the public's willingness to comply. However, individual differences in following the official public health recommendations for stopping the spread of COVID-19 have not yet to our knowledge been assessed. This study aims to fill this gap by assessing the sociodemographic and psychological correlates of implementing public health recommendations that aim to halt the COVID-19 pandemic. We investigate these associations in the context of France, one of the countries that has been most severely affected by the pandemic, and which ended up under a nationwide lockdown on March 17. In the next sections we describe our theoretical expectations over the associations between sociodemographics, personality, ideology, and emotions with abiding by the COVID-19 public health measures. We then test these hypotheses using data from the French Election Study.

COVID-19 paradoxical duality: there is a tendency to be optimistic about one’s own risk of infection (private optimism) & at the same time to be pessimistic about the risk to others (public pessimism)

Globig, Laura K., Bastien Blain, and Tali Sharot. 2020. “When Private Optimism Meets Public Despair: Dissociable Effects on Behavior and Well-being.” PsyArXiv. May 29. psyarxiv.com/gbdn8. Final version Perceptions of personal and public risk: Dissociable effects on behavior and well-being. Laura K. Globig, Bastien Blain & Tali Sharot. Journal of Risk and Uncertainty, Apr 2 2022. https://link.springer.com/article/10.1007/s11166-022-09373-0

Abstract: When faced with a threat, peoples’ estimate of risk guides their response. When danger is to the self as well as to others two estimates are generated: the risk to oneself and the risk to others. As these estimates likely differ, it is unclear how exactly they drive a response. To answer this question, we studied a large representative sample of Americans facing the COVID-19 pandemic at two time points (N1=1145, N2=683). We discover a paradoxical duality: a tendency to be optimistic about one’s own risk of infection (private optimism) while at the same time to be pessimistic about the risk to others (public pessimism). These two estimates were found to be differentially related to affect and choice. First, private optimism, but not public pessimism, was associated with people’s positive feelings. The association between private optimism and positive affect was mediated by people’s sense of agency over their future. However, negative affect was related to both private risk perception and public risk perception. Second, people predominantly engaged in protective behaviors based on their estimated risk to the population rather than to themselves. This suggests that people were predominantly engaging in protective behaviors for the benefit of others. The findings are important for understanding how people’s beliefs about their own future and that of others are related to protective behaviors and well-being.

Discussion

Surveying a representative sample of Americans over two time points during the pandemic of 2020 we found that many people believed COVID-19 posed a significant health danger to humans and perceived the risk of an average person to get COVID-19 as high. However, the majority did not consider their own risk to be high in absolute terms, nor higher relative to others their age and gender (see also Kuper-Smith et al., 2020; Wise et al., 2020). The question we posed was how these different perceptions of risk were related to psychological well-being and behavior. We found that individuals who believed they were less at risk of being infected by COVID-19 than others were happier. However, believing COVID-19 posed a great danger to humanity was unrelated to people’s happiness. This suggest that one’s perceived risk relative to others is especially important for people’s positive affect, while perceived risk to humanity is not. At the same time, both risk perceptions were related to anxiety. People who believed COVID-19 was a risk to themselves and/or to the human race tended to be more anxious. This suggests that while perceived relative personal risk relates to both positive and negative affect, perceived public risk relates only to negative affect.

Surprisingly, the likelihood that individuals complied with behavioral recommendations to mitigate the risk of COVID-19 was related to their views regarding the danger the virus poses to people in general, but not significantly related to whether they believed they themselves were at high risk. That is, people who believed the virus posed a great danger to humanity reported putting greater effort in social distancing, handwashing and avoiding touching their faces. Believing that the virus posed an especially high risk to the self was, however, unrelated to these behaviors. This effect remained even when accounting for anxiety and replicated across both time points. We thus speculate that the main motive for behavioral compliance was reducing the risk to the population as a whole, rather than the risk to the self. This in accordance with recent findings suggesting that public health messaging which focus on the concern for the greater good and responsibilities towards others may help induce behavioral compliance (Everett et al., 2020). Indeed, this may explain the success of the British Government’s message during the pandemic—"Stay Home. Protect the NHS. Save Lives” -which focused not on saving oneself but on saving “lives” and saving the national health service.

We tested the same subjects across two times—at the beginning of the crisis when states were moving into lockdown (time 1) and a month later when states were under lockdown (time 2). Interestingly, we observed a positive change in subjects’ well-being. A month into lockdown anxiety was lower than it was when states were just entering lockdown, happiness was greater and participants’ perception of the danger of COVID-19 to humanity was lower. These results align with past studies showing that humans adapt well to adversities and environmental change (Bonanno et al., 2002, 2004; Brickman et al., 1978; Dijkers, 1997; Frederick & Loewenstein, 1999).

In general people exhibited significant resilience during the pandmic with half of the population indicating they were as, or more happy as other times in their lives. The strongest predictor of happiness was a sense of control. Those who believed they had agency over their own life were happier, less anxious and perceived the danger COVID poses to themsleves and others as lower. In fact, the positive relationship between perceived personal risk and happiness was partially related to people’s sense of control. These results align with the suggestions that a sense of control is related to both optimism (Harris, 1996; Helweg-Larsen & Shepperd, 2001; Klein & Helweg-Larsen, 2002; Zakay, 1984) and overall well-being (Lachman & Weaver, 1998; Larson, 1989).

Here we examined people’s attitudes regarding a specific threat—COVID-19. There is some evidence, however, that the results generalize to other threats. For example, following the financial collapse of 2008 polls showed that people were pessimistic about the financial future of their country, less so about their own financial prospects (Ipsos MORI, 2008). Moreover, people perceive their fatality risk from natural disasters as below average (Viscusi & Zeckhauser, 2006), and with regards to climate change, people express little concern about the likely effects of climate change in their own region, but are more pessimistic with regards to the effects on their nation and the planet as a whole (Dunlap and Gallup, 1993). Such markedly different estimates of risk to oneself and others may arise because when estimating their own risk individuals assign more weight to their direct experience than to the experience of others (Viscusi & Zeckhauser, 2015). In other words, as most individuals were not infected by COVID themselves nor experienced a natural disaster, they estimate their own future risks in these domains as lower than the known risk in the population. Another factor contributing to this dissociation is people’s tendency to be overly optimistic about their own prospects relative to others (Sharot, 2011; Weinstein, 1980), which arises as people update their beliefs about their own vulnerability to a larger extent when receiving good news than when receiving bad news (Sharot et al., 2011). Moreover, past studies have shown that different moderators influence people’s perception of risk to oneself and to others, with factors associated with negative affect and sense of control primarily influencing personal risk estimates (for review see Helweg-Larsen & Shepperd, 2001).

Future studies are needed to examine whether the effects on well-being and behavior reported in this study generalize to other threats such as war, financial collapse and climate change. The results of such studies would be important for predicting the impact of such threats on people’s well-being and for understanding when and why people are likely to change their behavior to mitigate risk. For example, similar to the findings reported here, it is possible that the likelihood that people make “green choices” is related to their belief that climate change poses a threat to humanity, regardless of whether they believe it poses a perceived relative personal risk. Such knowledge can be useful for advocates and policy makers in framing information to nudge individuals to select actions that protect themselves and others from natural and man-made threats.

Mental health consequences of minority political positions: The case of brexit

Mental health consequences of minority political positions: The case of brexit. Christopher W. N. Saville. Social Science & Medicine, May 29 2020, 113016. https://doi.org/10.1016/j.socscimed.2020.113016

Highlights
• Previous group density studies correlational and unable to establish causation.
• Novel identities from UK's EU referendum allow study of formation of this effect.
• Density effect evident post-referendum but not beforehand.
• Effect robust to adjustment for a number of possible confounding variables.

Abstract:
The group density effect, where a group member's psychiatric risk is associated with the proportion of the local population their group comprises, demonstrates the importance of minority group status to mental health. Previous research, focusing on ethnicity, has been correlational, but newly-formed identities provide opportunities for natural experiments, with greater scope for causal inference. This study examines whether such a group density effect can be found for the novel Brexit identities of ‘leaver’ and ‘remainer’ following the UK's divisive 2016 referendum on EU membership. Mixed effects models were fitted to the Understanding Society panel survey series (N = 25,555, 19,767 for analyses controlling for pre-referendum mental health data), predicting mental health as a function of individual opinion on EU membership and local referendum results. These interacted such that those holding the local majority opinion had better mental health (Odds ratio (OR):875 [0.766- 0.9995]), compared to those in the minority. This result survived adjustment for individual and area-level economic circumstances (OR:866 [0.758-0.989]), and, strikingly, pre-referendum mental health (OR: 0.841 [0.709-0.998]), as well as a number of other potential confounding variables. The results provide evidence for rapidly forming group density effects based on de novo identities, and suggest that identity may be a causal mechanism for group density effects more broadly. They also speak to the extent of polarisation in the Brexit-era UK, and its public health consequences.

Keywords: UKBrexitEthnic densitySocial identity theoryInter-group relationsGroup densitySocial epidemiologyPublic mental health

Negative views of transgressors can be countered by them thinking that unethical behavior is morally unacceptable & emotions such as guilt; there is a moral superadditivity effect: less negative views from combination

Paruzel-Czachura, Mariola, and Michal Bialek. 2020. “The Moral Superadditivity Effect: Transgressors’ Beliefs and Emotions Influence the Perception of Their Morality.” PsyArXiv. May 28. doi:10.31234/osf.io/e8nbt

Abstract: Negative impressions of moral transgressors can be countered by them expressing socially desirable beliefs (thinking that unethical behavior is morally unacceptable) and emotions (such as guilt). Across four experiments with N = 1178, we establish a moral superadditivity effect, whereby jointly signaling socially desirable beliefs and emotions adds more than one could gain from them separately. This effect is visible when directly comparing the moral character of several transgressors (Studies 1 and 2) but disappears when judging them independently (Studies 3 and 4). Additionally, internal metanalysis showed that the benefits of expressing guilt and desirable beliefs are of similar strength, and that both are much larger when participants compare different types of transgressors directly.

Only about 41% of US adults indicated awareness of the race gap in IQ

US Public Perceptions of an Intelligence Quotient Test Score Gap Between Black Americans and White Americans. LJ Zigerell. Political Studies Review, May 27, 2020. https://doi.org/10.1177/1478929920917843

Abstract: Intelligence quotient (IQ) is a common measure of intelligence that associates with many important life outcomes. Research over several decades has indicated that the average IQ test score among Black Americans is lower than the average IQ test score among White Americans, but in weighted results from a national nonprobability survey, only about 41% of US adults indicated awareness of this IQ gap. Results from a follow-up convenience survey indicated that, in the aggregate, White participants’ rating of White Americans’ average IQ and average intelligence is higher than Blacks Americans’ average IQ test score and average intelligence and was not driven by White participants’ belief in a universal White intellectual superiority. These and other results could have implications regarding the US public’s perceptions about the reasons for Black/White inequality and implications for the use of intelligence stereotype scales as measures of racial prejudice.

Keywords: intelligence quotient, IQ, intelligence, stereotypes, race, perceptions, inequality

Contemporary attitudes toward migration are rooted in our evolutionary past; behavioral patterns from an evolutionary perspective—a negative attitude as well as openness—make sense

Factors affecting attitudes toward migrants—An evolutionary approach. Alexander Schahbasi  Susanne Huber  Martin Fieder. American Journal of Human Biology, May 26 2020. https://doi.org/10.1002/ajhb.23435

Abstract
Objective: To understand migration from an evolutionary perspective, this phenomenon has so far been mainly investigated in animal species. We therefore aim to investigate the potential evolutionary roots of attitudes toward migrants in humans.

Methods: We used data from the European Social Survey (n = 83 734), analyzing attitudes toward migrants by performing ordinal mixed models.

Results: We found that men have a more restrictive attitude toward migration than women, which increases with age and is stronger with a child in the household. Attitude toward migrants is also more skeptical if migrants have a different ethnicity and are from poorer countries. Increasing education and religiousness are associated with a more positive attitude toward migrants, particularly toward migrants of different ethnicity and from poorer countries.

Discussion: Although migration flows are a hallmark of the human species, previous findings suggest that (pre‐)historic migration flows were at times accompanied by conflict and violence, while at the same time, they insured survival by allowing cultural exchange and the avoidance of inbreeding. Accordingly, we assume that contemporary attitudes toward migration are rooted in our evolutionary past. We discuss the respective behavioral patterns from an evolutionary perspective, arguing that both—a negative attitude as well as openness—make sense.

4 DISCUSSION

Overall (integrating all countries and rounds of the ESS), we find that the majority of respondents prefer moderate migration (ie, “allow some to come”), particularly if migrants have the same ethnic background. A very open attitude toward migration (“allow many to come”) is only favored by a minority, and this open attitude is declining the more “out‐group” the migrants are (from 24.56% for migrants of the same ethnicity to 14.94% and 13.99% for migrants of different ethnicity and poorer countries, respectively). We further find that men are generally more skeptical toward migration than women. Odds ratios further indicate that this difference between men and women is higher if migrants have different ethnic background or come from poorer countries.

We would argue that these differences in attitudes between men and women may also be rooted in our evolutionary past. The genome—as a chronicler of past sexual encounters—reveals much about past (and particularly prehistoric) human interactions. In Europe, for instance, the main genetic component before the arrival of the Yamnaya consisted of the Anatolian farmers and small populations of ancient hunter gatherers. The arrival of the Yamnaya people in Europe about 5000 years age (Fu et al., 2016; Goldberg et al., 2017; Reich, 2018) dramatically changed the genetic landscape of Europe, particularly the paternal lines of heredity: the proportion of Y‐chromosomes inherited from the residential Anatolian farmers (who entered Europe approximately 8000 years ago) and the remaining ancient hunter gatherer populations (being in Europe since 40.000 years) declined rapidly after the arrival of the male‐biased Yamnaya migration (Goldberg et al., 2017) and even became extinct in some regions (Olalde et al., 2019). Both in Europe and also the Indian subcontinent, the Y‐chromosomal data indicate that the newly arriving migrants mixed with the resident female population, to the massive disadvantage of the local male population, leading to a virtual extinction of the residential male population (described in Reich, 2018). The Yamnaya themselves emerged out of an admixture of two populations some 7000 to 5000 years ago formed through a steady genetic influx from two populations from the south into the Steppe (Ukraine/Russia) (Haak et al., 2015). They grew in size and eventually headed west and also south‐east as far as India. But not only the Yamnaya expansion is an impressive example for a displacement of ancient residential male populations but also the Anglo Saxon invasion in Britain (Weale, Weiss, Jager, Bradman, & Thomas, 2002) and most recently the male dominated colonization of the Americas (Reich et al., 2012).

On the other hand, there are also numerous examples of—presumably—less violent prehistoric migrations, which eventually led to the admixture of different populations in the long run; such as the migration of Anatolian farmers, that led to an almost replacement of the resident hunter‐gatherer population and a very slow admixture among both groups. This rather slow migration of agriculturalist families over a longer period of time from Anatolia to Europe ~8000 years ago (Fu et al., 2016; Goldberg et al., 2017; Nielsen, Akey, Jakobsson, et al., 2017; Skoglund et al., 2012) first resulted in “parallel societies” of resident hunter‐gatherers and agriculturalist but later led to an admixture of both populations. In this case, no evidence of the sex‐specific admixture has been found. However, in both cases, after the Anatolian expansion as well as after the Yamnaya spread, data indicate a resurgence of the genetic representation of the residential inhabitants: during the Middle Neolithic, hunter‐gatherer ancestry rose again after its Early Neolithic decline, and then between the Late Neolithic and the present, when farmer and hunter‐gatherer ancestry rose after its Late Neolithic decline (Haak et al., 2015). Archeological evidence indicates that the rather slow migration wave from Anatolia seems to have been less violent compared to the Yamnaya expansion, but recent data also suggest that violence also has been occurred during the Anatolian expansion (Alt et al., 2020).

From the perspective of evolutionary psychology, however, the examples of violent encounters (Jantzen et al., 2011; Wild et al., 2004) might at least partially explain why men are more skeptical toward migration. In addition, the Y‐chromosomal asymmetric mixing contributes evidence to the long debated question if male aggression and violence would be adaptive or not, in particular, inter‐group aggression and killing (Archer, 2009, Daly, 2015, Macfarlan, Walker, Flinn, & Chagnon, 2014, Glowacki & Wrangham, 2015, reviewed in Wrangham, 2018). Clearly, the invading Yamnaya mended have reproductive and thus evolutionary benefits.

Our data also show that women are not per se more migration friendly compared tome but that in women more than in men, attitude toward migration changes with age. As women grow older, they become increasingly more skeptic of migration, whereas younger women are on average more migration friendly. This “friendliness” in younger women might be interpreted in the light of female dispersal (Huber, Zahourek, & Fieder, 2017). In the Paleolithic, hunter‐gatherer mating networks (Sikora et al., 2017) may have existed, which may have helped to avoid inbreeding by “marriage migration” between groups. Particularly, young women may have left their natal group to live with their husband's family (Seielstad, Minch, & Cavalli‐Sforza, 1998; Sterck, 1998; Towner, 2002), a scenario, where friendliness toward strangers would probably be advantageous. In addition, in the case of hostile group encounters, women have faced a substantially lower danger of being injured or killed (Wrangham, 2018) which was particularly true if they had a more out‐group friendly attitude. Furthermore, openness toward strangers may have fostered cultural exchange between groups that in terms of acquired and transmitted practices and techniques may have been advantageous for survival in hostile environments (Henrich, 2015). The finding that women may become more skeptical toward migration with increasing age, may also be interpreted on the basis of theory on general intelligence with a ability to learn new information and seek novel experiences at younger ages and a later life combination of these information and experiences to a “crystallized knowledge” (Geary, 2004). These findings indicate that selection may be acting at least to some extent antagonistically in men and in women (Connallon, Cox, & Calsbeek, 2010).

Overall, increasing age is associated with a more skeptical attitude toward migrants in both men and women. Although odds ratios indicate that the increase per year of life is rather small, over the whole life span, this effect accumulates to result in a substantial shift from a more positive to a more skeptic attitude. This finding is in line with the literature on changes of attitudes during the course of life (Visser & Krosnick, 1998).

The finding that having at least one child in the household (a rough proxy of ever reproducing) is associated with a more skeptical attitude toward migration of people of different ethnicity and from poorer countries indicates that individuals who have reproduced have a more critical attitude toward some kinds of migration compared to never reproducing individuals. We can only speculate why this is the case. Maybe parents are worrying for the future of their progeny, if the social tensions that are at times associated with migration are taken into account.

Our data further show that two parameters may have the potential to lower skepticisms toward migration: education and religiousness. Higher education is not only associated with a positive attitude toward migration, in particular toward migration of different ethnic background. Indicated by the odds ratios, the size of the effect of education, increasing from the lowest to the highest education level and leading to a higher acceptance of migrants particularly from a different culture, is comparable to that of sex. This migration‐friendly attitude may be interpreted as an effect of education per se, as education particularly in western societies is usually strong emphasizing mutual understanding and tolerance (Craft, 2017). However, individuals with higher education are usually better off in terms of resources compared to less educated people. As a result, higher educated individuals are usually less directly affected by migration, for instance, in terms of competition on the job or housing market (Collier, 2013).

Also religiousness is associated with a more positive attitude toward migration. Odds ratios indicate that over the full scale, religiousness has a comparable effect size as sex and education. This more positive attitude may be interpreted by the charitable characteristics of religion and the highly inclusive potential of some religions (Huber & Fieder, 2018; Norenzayan, 2013). This view is supported by the finding that the positive attitude is even higher if migrants have different ethnic background or come from poorer countries. Hence, this finding could be an indication for the integrative power of some religions even though religions also have a clearly excluding character, leading to intergroup conflicts (Seul, 1999). Nonetheless, the tendency to integrate individuals from different ethnic background maybe interpreted by the integrative power of religions during the agricultural revolution—when people with a different ethnic and cultural background settled into larger agglomerations (Norenzayan et al., 2016)—as well as inherent moral dogmas. However, our sample is by far mostly from predominantly “Christian countries.” In the models we calculated separately for the only predominantly Muslim country in our sample “Turkey” (only Muslims, parents born in Turkey and no experience of discrimination reported), we found no significant association between religious intensity and attitude to migrants whatsoever (data not shown).

As expected, a more right wing political attitude is associated with a more restrictive attitude toward migrants, particularly if migrants have a different ethnicity or are from poorer countries. As political attitude is encoded on an 11‐item scale, over the total range of the scale, despite rather small odds ratios, the association of the political attitude with the attitude toward migration is substantial. An association between right wing orientation and skepticism toward migration has also been demonstrated by Hatemi and McDermott (2012). Also, twin studies have shown that political attitude has a genetic basis (Hatemi & McDermott 2012) and in‐group favoritism has in part a genetic basis that may contribute to this trait. The variance in “in‐group favoritism” explained by inheritance in twin studies is varying greatly from 18% to 79% depending on the actual trait surveyed and how the in‐group has been defined (Kandler, Lewis, Feldhaus, & Riemann, 2015; Lewis, Kandler, & Riemann, 2014; Loehlin, 1993). Constructing a sum indicator of all three questions on the attitudes toward migrants and regressing political attitude on this indicator, attitude toward migrants explains about 16% of the variance in political attitude of the survey participants. Hence, as expected, the attitude toward strangers and political orientation is associated and explains a certain proportion of variance. Overall, we assume that political orientation is a trait that evolved in an interplay between genes and the environment (Alford et al., 2011; Hatemi & McDermott, 2012), that is, as a process of a cultural genetic coevolution (Richerson, Boyd, & Henrich, 2010). As political orientation has a rather strong genetic basis, both left wing and right wing political orientation should have brought benefits to the bearer from an evolutionary point of view. Accordingly, political orientation (both left and right) is related to the number of offspring, indicating reproductive advantages for the political extreme (Fieder & Huber, 2018). However, this pattern shifted in Western industrial countries to only a reproductive advantage for the political right (Fieder & Huber, 2018). In line with Stearns, Byars, Govindaraju, and Ewbank (2010), it can be assumed that this reproductive differential maybe suitable to indicate selective forces for political orientation.

The overall more reluctant attitude to migrants of a different ethnicity compared with the attitude toward migrants of the same ethnicity may indicate some sort of ethnic nepotism toward more similar individuals (Rushton, 1989, Salter & Harpeding, 2013), thus humans may have preferred individuals where they detected genetic similarity and that such a behavior may have overall enhanced fitness (Rushton et al., 1985, Rushton, 1989, Salter & Harpeding, 2013). On basis of data from 183 countries worldwide, Vanhanen found evidence that ethnic division tends to lead to conflicts of interest between ethnic groups and that the more a society is ethnically divided, the more political and other conflicts arise along ethnic line (Vanhanen, 1999), as well as intensities along religious borders (Salter, 2018). Also, ethnic nepotism maybe adaptive if it helps to secure resources and territory (Salter, 2002). Furthermore, religious and ethnic homogamy increases the average number of children and decreases childlessness (Fieder & Huber, 2016b; Huber & Fieder, 2018). It has been demonstrated on the basis of data from Iceland, that average offspring number decreases with genetic relatedness from second‐order cousins on (Helgason, Pálsson, Guðbjartsson, & Stefánsson, 2008) and thus during our evolutionary past moderate inbreeding may have led to reproductive benefits (Fox, 2015).

Ethnic nepotism may have some serious drawbacks, as individuals may become overall—or for certain traits—more homozygote with all the known consequences (Clark et al., 2019, Fieder, Huber, & Martin, n.d., submitted). Particularly in small‐scale societies of mostly not more than 150 individuals (Dunbar, 1993), the burden of inbreeding may have been large in the case of ethnic nepotism. Ethnic nepotism and the rejection of strangers, as well as a more open attitude toward strangers, always depend on the actions of others. Therefore, such an adopted strategy may lead to an evolutionary stable strategy under certain conditions (Smith, 1976) with different characteristics within a group. Ethnic nepotism has no concept of “ethnic kinship” (such as kinship between parents and children) that would make this more distant “altruism” reasonable. A way out of this dilemma has been proposed by Jones (2018), indicating that ethnic is nepotism expressed by a group toward their own kin and thus individuals of similar phenotypes. In‐group marriages in small groups fostered genetic relatedness also among individuals that are more distantly related than close kin and thus in‐group cooperation among individuals that are genetically more related as indicated by simple kinship. An argument quite closely related to Hamilton (Hamilton, 1964, 1971) and West et al. (2011). Accordingly, William D. Hamilton also argued that successfully expanding groups are expected to evolve to some extent a degree of xenophobia (Hamilton, 1996). But ethnic nepotism may have resulted in high levels of inbreeding with all the related consequences and thus a process of balancing selection may have been beneficial: some individuals with a propensity for an increased out‐group cooperation.

Thus we assume that balancing selection may help to explain the attitudes toward strangers: both a more open attitude as well as a more guarded attitude may have led to benefits for the bearer, and so both attitudes have been kept in the population (Charlesworth, 2006; Fieder & Huber, 2018)—presumably at different frequencies, depending on the environment and circumstances. Evidence for a balancing selection on the “attitudes to strangers” maybe found in the polymorphisms of alleles that are associated with this attitude. If balancing selection would have been acting on alleles associated with attitudes toward strangers, balancing selection may have increased the polymorphism of loci that are associated with the trait “attitude toward strangers”. We are not aware of any GWA study that already identified loci associated with the attitude toward in‐group vs out‐group members; hence, this argument remains speculative at the moment. One hint for balancing selection is evidence from the World Value Survey: as in the case of political attitude, individuals with a more critical attitude toward strangers have on average more children (data not published). Balancing selection may explain different attitudes toward strangers, while differences between men and women may be additionally explained by a “sex‐specific selection”. The same trait may lead to different reproductive outcomes for men and women and thus for different selection pressures on the sexes (Connallon et al., 2010).

Our data set provides no information on the attitude toward strangers and pathogen prevalence, but pathogens may have also been important in shaping our attitude toward strangers. Infectious diseases clearly increased morbidity and mortality throughout human history; this may particularly hold true since the rise of agricultural societies and thus more dense human populations (Wolfe, Dunavan, & Diamond, 2007). Previous research demonstrated worldwide variability in pathogen prevalence, predicting some cultural differences ranging from food habits (Sherman & Billing, 1999), marriage structures (Low, 1990), parenting practices (Quinlan, 2007), and mate choice (Gangestad & Buss, 1993). Interestingly, it seems that attitudes of collectivism (eg, ethnocentrism, conformity) can inhibit the transmission of pathogens. Fincher, Thornhill, Murray, and Schaller (2008) demonstrated on the basis of worldwide data that the regional prevalence of pathogens correlates strongly positive with cultural indicators of collectivism but strongly negative with individualism. However, admixture and thus heterozygosity may help to cope better with diseases and infections, as heterozygosity seems to improve also the health condition of individuals and thus may increase protection against pathogens (Clark et al., 2019). This may especially hold true for major histocompatibility complex heterozygosity (Penn, Damjanovich, & Potts, 2002; Xu et al., 2019).

From an evolutionary point of view, a more negative attitude toward migrants and a positive attitude toward migrants make sense: In some cases, migration may include violence with detrimental outcomes for certain groups (particularly men). On the other hand, isolation may lead to lack of cultural exchange and to an increase in inbreeding.1Considering the size of populations in contemporary Europe, inbreeding avoidance has to be considered an evolutionary inherited trait as it has limited relevance today. Also, the necessity of cultural exchange to thrive (Henrich, 2015) has been altered by contemporary technology allowing global communication and information exchange.

Our findings are also in line with Eibl‐Eibesfeldt, who suggested that with regard to strangers, humans are “an ambivalent species,” displaying both timidity and interest—particularly in the case of recurring interactions (Eibl‐Eibesfeldt, 1986). Thus, in our evolutionary history, both traits may have been crucial for survival and we assume that both—evolutionary acquired—predispositions are still present in contemporary populations and influence the perception of migration flows. Migration‐friendly vs migration‐skeptical attitude may serve as an example of a genetic cultural coevolution (Henrich, 2015; Richerson et al., 2010). As our data are based on European populations, our conclusions are, of course, limited to this group.

To conclude, we would like to stress that it is of utmost importance to note that evolutionary acquired mind‐sets are not a predicament. Human behavior has in many ways improved during the history of our species, taming detrimental instincts and making us “better angels or our nature” as Steven Pinker put it (Pinker, 2011).