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When someone violates a social norm, others may think that some sanction would be appropriate. We examine how the experience of emotions like anger and disgust relate to the judged appropriateness of sanctions, in a pre-registered analysis of data from a large-scale study in 56 societies. Across the world, we find that individuals who experience anger and disgust over a norm violation are more likely to endorse confrontation, ostracism and, to a smaller extent, gossip. Moreover, we find that the experience of anger is consistently the strongest predictor of judgments of confrontation, compared to other emotions. Although the link between state-based emotions and judgments may seem universal, its strength varies across countries. Aligned with theoretical predictions, this link is stronger in societies, and among individuals, that place higher value on individual autonomy. Thus, autonomy values may increase the role that emotions play in guiding judgments of social sanctions.

The emergence of COVID-19 dramatically changed social behavior across societies and contexts. Here we study whether social norms also changed. Specifically, we study this question for cultural tightness (the degree to which societies generally have strong norms), specific social norms (e.g. stealing, hand washing), and norms about enforcement, using survey data from 30,431 respondents in 43 countries recorded before and in the early stages following the emergence of COVID-19. Using variation in disease intensity, we shed light on the mechanisms predicting changes in social norm measures. We find evidence that, after the emergence of the COVID-19 pandemic, hand washing norms increased while tightness and punishing frequency slightly decreased but observe no evidence for a robust change in most other norms. Thus, at least in the short term, our findings suggest that cultures are largely stable to pandemic threats except in those norms, hand washing in this case, that are perceived to be directly relevant to dealing with the collective threat. Tightness-looseness theory predicts that social norms strengthen following threat. Here the authors test this and find that, after the emergence of the COVID-19 pandemic, hand washing norms increased, but no evidence was observed for a robust change in most other norms.

Using a common pool resource game protocol with voting we examine experimentally how cooperation varies with the level at which (binding) votes are aggregated. Our results are broadly in line with theoretical predictions. When players can vote on the behavior of the whole group or when leaders from each group can vote for the group as a whole, extraction levels from the common resource pool are close to the social optimum. When players extract resources individually, there is substantial overextraction. When players vote in subgroups, there is initially less overextraction but it increases over time. This suggests that in order for binding voting to overcome the tragedy of the commons in social dilemmas, it should ideally affect the group as a whole.

To examine the evolutionary basis of a behavior, an established approach (known as the phenotypic gambit) is to assume that the behavior is controlled by a single allele, the fitness effects of which are derived from a consideration of how the behavior interacts, via life-history, with other ecological factors. Here we contrast successful applications of this approach with several examples of an influential and superficially similar line of research on the evolutionary basis of human cooperation. A key difference is identified: in the latter line of research the focal behavior, cooperation, is abstractly defined in terms of immediate fitness costs and benefits. Selection is then assumed to act on strategies in an iterated social context for which fitness effects can be derived by aggregation of the abstractly defined immediate fitness effects over a lifetime. This approach creates a closed theoretical loop, rendering models incapable of making predictions or providing insight into the origin of human cooperation. We conclude with a discussion of how evolutionary approaches might be appropriately used in the study of human social behavior. (C) 2017 Elsevier Inc. All rights reserved.

Game theory is a formal approach to behavior that focuses on the strategic aspect of situations. The game theoretic approach originates in economics but has been embraced by scholars across disciplines, including many philosophers and biologists. This approach has an important weakness: the strategic aspect of a situation, which is its defining quality in game theory, is often not its most salient quality in human (or animal) cognition. Evidence from a wide range of experiments highlights this shortcoming. Previous theoretical and empirical work has sought to address this weakness by considering learning across an ensemble of multiple games simultaneously. Here we extend this framework, incorporating artificial neural networks, to allow for an investigation of the interaction between the perceptual and functional similarity of the games composing the larger ensemble. Using this framework, we conduct a theoretical investigation of a population that encounters both stag hunts and prisoner's dilemmas, two situations that are strategically different but which may or may not be perceptually similar.

BACKGROUND: Medical treatments with no direct effect (like homeopathy) or that cause harm (like bloodletting) are common across cultures and throughout history. How do such treatments spread and persist? Most medical treatments result in a range of outcomes: some people improve while others deteriorate. If the people who improve are more inclined to tell others about their experiences than the people who deteriorate, ineffective or even harmful treatments can maintain a good reputation.

OBJECTIVE: The intent of this study was to test the hypothesis that positive outcomes are overrepresented in online medical product reviews, to examine if this reputational distortion is large enough to bias people's decisions, and to explore the implications of this bias for the cultural evolution of medical treatments.

METHODS: We compared outcomes of weight loss treatments and fertility treatments in clinical trials to outcomes reported in 1901 reviews on Amazon. Then, in a series of experiments, we evaluated people's choice of weight loss diet after reading different reviews. Finally, a mathematical model was used to examine if this bias could result in less effective treatments having a better reputation than more effective treatments.

RESULTS: Data are consistent with the hypothesis that people with better outcomes are more inclined to write reviews. After 6 months on the diet, 93% (64/69) of online reviewers reported a weight loss of 10 kg or more while just 27% (19/71) of clinical trial participants experienced this level of weight change. A similar positive distortion was found in fertility treatment reviews. In a series of experiments, we show that people are more inclined to begin a diet with many positive reviews, than a diet with reviews that are representative of the diet's true effect. A mathematical model of medical cultural evolution shows that the size of the positive distortion critically depends on the shape of the outcome distribution.

CONCLUSIONS: Online reviews overestimate the benefits of medical treatments, probably because people with negative outcomes are less inclined to tell others about their experiences. This bias can enable ineffective medical treatments to maintain a good reputation.

In this article, we outline the current state of research concerning cooperation in the cross-national context. We present several theoretical approaches and empirical findings regarding national differences in cooperation, as well as how cooperation may depend on the national background of the interaction partner. In addition, we discuss the influence of (national) group norms, cultural similarity, and ingroup membership. This review concludes with a call for research on cooperation to include more non-WEIRD nations and more systematically cover national background as one important social category determining the willingness to cooperate.

Cross-cultural studies have found national differences in how concerned people are about online privacy. However, it has not yet been settled what causes this variation, and several factors have been proposed in the literature, including internet habituation, individualism, and uncertainty avoidance. Here we investigate these factors by two studies. In the first, we examine the association between online privacy concerns and a new measure of online self-disclosure norms that we introduce. We find that this measure is significantly associated with two established instruments of online privacy concerns in the literature. In the second, we analyze previously unpublished data from a questionnaire on online self-disclosure norms as assessed by this new measure. It includes replies from 18,046 adult respondents from 57 countries and six continents. We find that norms in favor of more restrictive online self-disclosure are weaker in countries with higher levels of internet penetration (r = −0.56, p < .001). Our findings suggest that higher internet penetration in a country reduces online privacy concerns. The results support the idea that habituation to online environments decreases privacy risk perceptions. An implication is that preferences for online privacy are likely to decline over time in countries where internet penetration is still low. Lastly, in conflict with previous studies, our analyses do not support the theory that online privacy concerns are associated with national cultures related to individualism or uncertainty avoidance as measured by Hofstede's indices. 

Alan Rogers (1988) presented a game theory model of the evolution of social learning, yielding the paradoxical conclusion that social learning does not increase the fitness of a population. We expand on this model, allowing for imperfections in individual and social learning as well as incorporating a "critical social learning" strategy that tries to solve an adaptive problem first by social learning, and then by individual learning if socially acquired behavior proves unsatisfactory. This strategy always proves superior to pure social learning and typically has higher fitness than pure individual learning, providing a solution to Rogers's paradox of nonadaptive culture. Critical social learning is an evolutionarily stable strategy (ESS) unless cultural transmission is highly unfaithful, the environment is highly variable, or social learning is much more costly than individual learning. We compare the model to empirical data on social learning and on spatial variation in primate cultures and list three requirements for adaptive culture. © 2007 by the American Anthropological Association.

Previous work on mathematical models of cultural evolution has mainly focused on the diffusion of simple cultural elements. However, a characteristic feature of human cultural evolution is the seemingly limitless appearance of new and increasingly complex cultural elements. Here, we develop a general modelling framework to study such cumulative processes, in which we assume that the appearance and disappearance of cultural elements are stochastic events that depend on the current state of culture. Five scenarios are explored: evolution of independent cultural elements, stepwise modification of elements, differentiation or combination of elements and systems of cultural elements. As one application of our framework, we study the evolution of cultural diversity (in time as well as between groups).

The ability to acquire knowledge and skills from others is widespread in animals and is commonly thought to be responsible for the behavioural traditions observed in many species. However, in spite of the extensive literature on theoretical analyses and empirical studies of social learning, little attention has been given to whether individuals acquire knowledge from a single individual or multiple models. Researchers commonly refer to instances of sons learning from fathers, or daughters from mothers, while theoreticians have constructed models of uniparental transmission, with little consideration of whether such restricted modes of transmission are actually feasible. We used mathematical models to demonstrate that the conditions under which learning from a single cultural parent can lead to stable culture are surprisingly restricted ( the same reasoning applies to a single social-learning event). Conversely, we demonstrate how learning from more than one cultural parent can establish culture, and find that cultural traits will reach a nonzero equilibrium in the population provided the product of the fidelity of social learning and the number of cultural parents exceeds 1. We discuss the implications of the analysis for interpreting various findings in the animal social-learning literature, as well as the unique features of human culture.

For a random graph on n vertices where the edges appear with individual rates, we give exact formulas for the expected time at which the number of components has gone down to k and the expected length of the corresponding minimal spanning forest.

For a random bipartite graph we give a formula for the expected time at which a k-assignment appears. This result has a bearing on the random assignment problem.

We give expressions for the expected number of inversions after t random adjacent transpositions have been performed on the identity permutation in Sn+1 The problem is a simplification of a problem motivated by genome evolution. For a fixed t and for all n greater than or equal to t, the expected number of inversions after t random adjacent transpositions is

E-nt = t - 2/n ((t)(2)) + Sigma(r=2)(t) (-1)(r)/n(r) [2(r)C(r)((t)(r+1)) + 4d(r) ((t)(r))]

where d(2) = 0, d(3) = 1, d(4) = 9, d(5) = 69,... is a certain integer sequence. An important part of the our method is the use of a heat. conduction analogy of the random walks, which guarantees certain properties of the solution.

We answer some questions concerning the so-called sigma -game of Sutner [Linear cellular automata and the Garden of Eden, Math. Intelligencer 11 (1989), 49-53]. It is played on a graph where each vertex has a lamp, the light of which is toggled by pressing any vertex with an edge directed to the lamp. For example, we show that every configuration of lamps can be lit if and only if the number of complete matchings in the graph is odd. In the special case of an orthogonal grid one gets a criterion for whether the number of monomer-dimer tilings of an m x n grid is odd or even. 

Kessler and Livingstone proved an asymptotic formula for the expected length of the largest part of a partition drawn uniformly at random. As a first step they gave an exact formula expressed as a weighted sum of Euler's partition function. Here we give a short bijective proof of a generalization of this exact formula to the expected length of the kth part.

Previous research shows that individuals with Asperger syndrome or high-functioning autism tend to have impaired processing of humor and laugh at things that are not commonly found funny. Here the relationship between humor styles and the broader autism phenotype was investigated in a sample of the general population. The autism-spectrum quotient (AQ) and the humor styles questionnaire (HSQ) were administered to six hundred US participants recruited through an Internet-based service. On the whole, high scores on AQ were negatively related to positive humor styles and unrelated to negative humor styles. However, AQ subscales representing different autism-spectrum traits exhibited different patterns. In particular, the factor "poor mind-reading" was associated with higher scores on negative humor styles and the factor "attention to detail" was associated with higher scores on all humor styles, suggesting a more nuanced picture of the relationship between autism-spectrum traits and humor.

At the end of their thoughtful target article, Andersson and Read conclude that formal models of cultural evolution are “useful but must be kept in perspective.” As a mathematician with a great interest in social science, I have some experience of working with such models. Based on this experience, I very much agree with the “but” part of the above conclusion. I see a clear tendency in the cultural evolution literature to put too much trust in the value of formal models.

Matematik är inte bara torra siffror. Det är resonemang och teori som är ämnets kärna. Matematiken erbjuder metoder som gör det svåra lättare att förstå. Därför behöver även humanister få sig lite matte till livs, menar matematikprofessorn Kimmo Eriksson.

This document presents a survey of the statistical and combinatorial aspects of four areas of comparative genomics: gene order based measures of evolutionary distances between species, construction of phylogenetic trees, detection of horizontal transfer of genes, and detection of ancient whole genome duplications.

Jasso (1978) proposed a universal law of justice evaluations describing a logarithmic relationship between the perceived injustice of a reward and the ratio between this reward and the just reward. In applications this model is treated as if it were exact, whereas analogous models in psychophysics have empirically established degrees of uncertainty. In this article I make the first assessment of the magnitude of error in the logarithmic model of justice evaluations, using published data and a novel experiment. For the standard application of the model, where just rewards are inferred from justice evaluations, I find that the inherent inaccuracy leads to errors of about 15% on average. I also compared the logarithmic model to 2 nonlogarithmic models. Almost 20% of my respondents made justice evaluations that were more consistent with one of the latter models, suggesting that no single model is really universal.

Mathematics is a fundamental tool of research. Although potentially applicable in every discipline, the amount of training in mathematics that students typically receive varies greatly between different disciplines. In those disciplines where most researchers do not master mathematics, the use of mathematics may be held in too much awe. To demonstrate this I conducted an online experiment with 200 participants, all of which had experience of reading research reports anda postgraduate degree (in any subject). Participants were presented with the abstracts from two published papers (one inevolutionary anthropology and one in sociology). Based on these abstracts, participants were asked to judge the quality of the research. Either one or the other of the two abstracts was manipulated through the inclusion of an extra sentence taken from a completely unrelated paper and presenting an equation that made no sense in the context. The abstract that included the meaningless mathematics tended to be judged of higher quality. However, this "nonsense math effect" was not found among participants with degrees in mathematics, science, technology or medicine.

Recent studies have found disapproval of peer punishment of norm violations. This seems puzzling, given the potential benefits peer punishers contribute to the group. We suggest part of the answer is that peer punishers tend to come across as aggressive and as such may be viewed as more problematic than beneficial to have around. We used simple computer animations of geometric shapes to enact 15 precise variations of social sanctions against a norm violator. More than 1,800 subjects were recruited to watch an animation and judge the behavior and character of the animated agents. They also completed a trait aggression measure. Across the variations peer punishment was typically disapproved of, especially when severe or openly aggressive, and especially by subjects low on trait aggression. We conclude that there seems to be a social norm against peer punishment and that dislike of aggressiveness seems to be part of the reason why.

Experiments on economic games typically fail to find positive reputational effects of using peer punishment of selfish behavior in social dilemmas. Theorists had expected positive reputational effects because of the potentially beneficial consequences that punishment may have on norm violators’ behavior. Going beyond the game-theoretic paradigm, we used vignettes to study how various social factors influence approval ratings of a peer who reprimands a violator of a group-beneficial norm. We found that ratings declined when punishers showed anger, and this effect was mediated by perceived aggressiveness. Thus the same emotions that motivate peer punishers may make them come across as aggressive, to the detriment of their reputation. However, the negative effect of showing anger disappeared when the norm violation was sufficiently severe. Ratings of punishers were also influenced by social distance, such that it is less appropriate for a stranger than a friend to reprimand a violator. In sum, peer punisher ratings were very high for a friend reprimanding a severe norm violation, but particularly poor for a stranger showing anger at a mild norm violation. We found no effect on ratings of whether the reprimand had the beneficial consequence of changing the violator’s behavior. Our findings provide insight into how peer punishers can avoid negative reputational effects. They also point to the importance of going beyond economic games when studying peer punishment. 

In the present article, we studied approximating pairs of numbers (a, b) that were used to estimate quantity in a single phrase ("two, three years ago"). Pollmann and Jansen (1996) found that only a few of the many possible pairs are actually used, suggesting an interaction between the ways in which people estimate quantity and their use of quantitative phrases in colloquial speech. They proposed a set of rules that describe which approximating pairs are used in Dutch phrases. We revisited this issue in an analysis of Swedish and American language corpora and in a series of three experiments in which Swedish and American adults rated the acceptability of various approximating pairs and created approximating pairs of their own in response to various estimation tasks. We found evidence for Pollmann and Jansen's rules in both Swedish and English phrases, but we also identified additional rules and substantial individual and cross-language variation. We will discuss implications for the origin of this loose "grammar" of approximating pairs.

Gender differences in achievement exhibit variation between domains and between countries. Much prior research has examined whether this variation could be due to variation in gender equality in opportunities, with mixed results. Here we focus instead on the role of a society's values about gender equality, which may have a more pervasive influence. We pooled all available country measures on adolescent boys' and girls' academic achievement between 2000 and 2015 from the Program for International Student Assessment (PISA) and Trends in International Mathematics and Science Study (TIMSS) assessments of math, science, and reading. We then analyzed the relation between gender differences and country levels of gender egalitarian values, controlling for country levels of living standards and indicators of gender equality in opportunities. Gender egalitarian values came out as the most important predictor. Specifically, more gender egalitarian values were associated with improved performance of boys relative to girls in the same countries. This pattern held in reading, where boys globally perform substantially worse than girls, as well as in math and science where gender differences in performance are small and may favor either boys or girls. Our findings suggest a previously underappreciated role of cultural values in moderating gender gaps in academic achievement.

Research on cultural transmission among Americans has established a bias for transmitting stories that have disgusting elements (such as exposure to rats and maggots). Conceived of as a cultural evolutionary force, this phenomenon is one type of emotional selection. In a series of online studies with Americans and Indians we investigate whether there are cultural differences in emotional selection, such that the transmission process favours different kinds of content in different countries. The first study found a bias for disgusting content (rats and maggots) among Americans but not among Indians. Four subsequent studies focused on how country interacts with kind of emotional content (disgusting vs. happy surprises and good news) in reactions to transmission of stories or information. Whereas Indian participants, compared to Americans, tended to be less interested in, and excited by, transmission of stories and news involving common disgust-elicitors (like rats), the opposite pattern held for transmission of happy surprises and good news (e.g., the opening of a new public facility). We discuss various possible explanations and implications. 

According to an influential theory in cultural evolution, within-group similarity of culture is explained by a human conformist-bias, which is a hypothesized evolved predisposition to preferentially follow a member of the majority when acquiring ideas and behaviours. However, this notion has little support from social psychological research. In fact, a major theory in social psychology (Latan and Wolf (1981) argues for what is in effect a nonconformist-bias: by analogy to standard psychophysics they predict minority sources of influence to have relatively greater impact than majority sources. Here we present a new mathematical model and an experiment on social influence, both specifically designed to test these competing predictions. The results are in line with nonconformism. Finally, we discuss within-group similarity and suggest that it is not a general phenomenon but must be studied trait by trait.

In one conception of cultural evolution, the evolutionary success of cultural units that are transmitted from individual to individual is determined by forces of cultural selection. Here we argue that it is helpful to distinguish between several distinct phases of the transmission process in which cultural selection can operate, such as a choose-toreceive phase, an encode-and-retrieve phase, and a choose-to-transmit phase. Here we focus on emotional selection in cultural transmission of urban legends, which has previously been shown to operate in the choose-to-transmit phase. In a series of experiments we studied serial transmission of stories based on urban legends manipulated to be either high or low on disgusting content. Results supported emotional selection operating in all three phases of cultural transmission. Thus, the prevalence of disgusting urban legends in North America may be explained by emotional selection through a multitude of pathways. 

Recent mathematical modeling of repeated cultural transmission has shown that the rate at which culture is lost (due to imperfect transmission) will crucially depend on whether individuals receive transmissions from many cultural parents or only from one. However, the modeling assumptions leading up to this conclusion have so far not been empirically assessed. Here we do this for the special case of transmission chains where each individual either receives the same story twice from one cultural parent (and retransmits twice to a cultural child) or receives possibly different versions of the story from two cultural parents (and then retransmits to two cultural children). For this case, we first developed a more general mathematical model of cultural retention that takes into account the possibility of dependence of error rates between transmissions. In this model, under quite plausible assumptions, chains with two cultural parents will have superior retention of culture. This prediction was then tested in two experiments using both written and oral modes of transmission. In both cases, superior retention of culture was found in chains with two cultural parents. Estimation of model parameters indicated that error rates were not identical and independent between transmissions; instead, a primacy effect was suggested, such that the first transmission tends to have higher fidelity than the second transmission.

A requirement of culture, whether animal or human, is some degree of conformity of behavior within populations. Researchers of gene-culture coevolution have suggested that population level conformity may result from frequency-biased social learning: individuals sampling multiple role models and preferentially adopting the majority behavior in the sample. When learning from a single role model, frequency-bias is not possible. We show why a population-level trend, either conformist or anticonformist, may nonetheless be almost inevitable in a population of individuals that learn through social enhancement, that is, using observations of others' behavior to update their own probability of using a behavior in the future. The exact specification of individuals' updating rule determines the direction of the trend. These results offer a new interpretation of previous findings from simulations of social enhancement in combination with reinforcement learning, and demonstrate how results of dynamical models may strongly depend on seemingly innocuous choices of model specifications, and how important it is to obtain empirical data on which to base such choices.

Three major theories could potentially explain why hygiene norms vary across societies: tightness-looseness theory, disease threat theory, and theory of a civilizing process driven by how self-control is valued. We test these theories using data from a study of 56 countries across the globe, in which almost 20,000 participants reported their norms about spitting in six different contexts, hand washing in six different contexts, and tooth brushing. Participants also reported the perceived tightness of their society, whether they perceived diseases as a threat to their society, and their valuation of self-control. In support of the civilizing process, most of the norms in our study (including most hand washing norms and most spitting norms) were stricter in countries where self-control is valued more highly. A few norms did not follow this main pattern and these norms were instead stricter in countries where disease was perceived as a greater threat. Thus, while the theory of a civilizing process received the strongest support, our data indicate that some combination with the disease threat theory may be required to fully explain country-variation in hygiene norms.

Strict norms about hygiene may sometimes have health benefits but may also be a burden. Based on research in the United States, it has been suggested that women traditionally shoulder responsibility for hygiene standards and therefore tend to have stricter views on hygiene. However, there is little systematic research on sex differences in hygiene norms at the global scale. We set up two hypotheses: (1) Stricter hygiene norms among women than among men is a global phenomenon. (2) The size of this sex difference varies across nations with the level of sex equality. We examine these hypotheses using data from a recent international survey (N = 17,632). Participants in 56 countries were asked for their views of where it is not appropriate for people to spit and in which situations people should wash their hands. As a measure of sex equality, we use an existing country-level measure of attitudes to equality between the sexes, available for 49 nations in the study. Stricter hygiene norms among women than among men are observed almost everywhere, but there are a few exceptions (most notably Nigeria and Saudi Arabia). The size of the sex difference in hygiene norms varies strongly with the level of sex equality, but in a non-linear way. The sex difference is most pronounced in moderately egalitarian countries with the highest recorded difference being in Chile. In more egalitarian parts of the world, more sex equality is associated with a smaller sex difference in hygiene norms. In the less egalitarian parts of the world, the opposite relation holds. We offer an interpretation in terms of what different levels of sex equality mean for the content of sex roles.

Summary.: The Braess Paradox is the counterintuitive fact that creation of a shortcut may make travel slower. As each driver seeks to minimize his/her travel time, the shortcut may become so popular that it causes congestion elsewhere in the road network, thereby increasing the travel time for everyone. We extend the paradox by considering a shortcut that is a single-lane but two-way street. The conflict about which drivers get to use the single-lane shortcut is an example of a game theoretic situation known as Chicken, which merges with the Braess Paradox into the novel Chicken Braess Paradox: meeting traffic may make travel quicker. 

Existing mathematical models suggest that gene-culture coevolution favours a conformist bias in social learning, that is, a psychological mechanism to preferentially acquire the most common cultural variants. Here we show that this conclusion relies on specific assumptions that seem unrealistic, such as that all cultural variants are known to every individual. We present two models that remove these assumptions, showing that: 1) the rate of cultural evolution and the adaptive value of culture are higher in a population in which individuals pick cultural variants at random ( Random strategy) rather than picking the most common one ( Conform strategy); 2) in genetic evolution the Random strategy out-competes the Conform strategy, unless cultural evolution is very slow, in which caseConform and Random usually coexist; 3) the individuals’ ability to evaluate cultural variants is a more important determinant of the adaptive value of culture than frequency-based choice strategies. We also review existing empirical literature and game-theoretic arguments for conformity, finding neither strong empirical evidence nor a strong theoretical expectation for a general conformist bias. Our own vignette study of social learning shows that people may indeed use different social learning strategies depending on context.

The "above-average effect" is the phenomenon that people tend to judge themselves above average on desirable traits. Based on social identity theory, we propose that a "below-average effect" may arise when individuals rate themselves and the average ingroup member on traits stereotypically associated with the ingroup. In two studies, Republican and Democrat participants rated themselves and the average political ingroup member on possession of desirable traits related to warmth and competence. Current political stereotypes in America associate the former dimension with Democrats and the latter with Republicans. Consistent with our hypothesis, the above-average effect was moderated by political group and dimension in interaction. In particular, Democrats rated themselves below the average Democrat on warmth and Republicans rated themselves below the average Republican on competence. 

Prior research has linked religiosity to certain forms of self-enhancement. We extend this literature by three studies linking religiosity to the well-established better-than-average effect (BAE). First, a reanalysis of self-judgments of desirable characteristics in 15 nations showed that the BAE was stronger in more religious countries, even taking into account gross domestic product, interdependence, and economic inequality. Second, in two online surveys totaling 1,000 Americans, the BAE was stronger among more religious individuals. Several observations indicated that this relation was due to individuals self-stereotyping with respect to their religious in-groups. In particular, the relation was restricted to characteristics on the warmth dimension, consistent with the religious stereotype, and the average religious in-group member tended to be judged even more favorably than self. The latter phenomenon, which we term humble self-enhancement, is consistent with other studies linking stronger religiosity to greater favoritism of the religious in-group and greater derogation of religious out-groups.