Evolutionary Psychological Science

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Participants’ willingness to divert trolley toward target
Article
  • Carey J. FitzgeraldCarey J. Fitzgerald
  • Jody A. ThompsonJody A. Thompson
  • Brittany LorentzBrittany Lorentz
The present study examined whether the induction of a mindful state would influence ethical decision making in a trolley problem that was modified to contain variables relevant to one’s inclusive fitness. N = 312 participants – half of which were presented with a guided mindfulness meditation – were presented with a modified trolley problem in which they were given a choice: let five strangers die, or divert the trolley toward a single target who will be killed by the trolley instead of the five strangers. This single target was manipulated to be one of the following five individuals: a stranger, the participant’s friend, cousin, sibling, or romantic partner. Participants in a mindful state were more likely to divert the trolley away from the five strangers when the individual target was a stranger, friend, or cousin. However, individuals in a mindful state were no more likely than controls to divert the trolley when the single target was a sibling or romantic partner. These results indicate that mindfulness may increase utilitarian decision making when the sacrificial target is not the participant’s close kin member or romantic partner.
 
Predicted direction of parameter estimates computed with a cascade model examining the effects of Military Technology, Military Technology Differentiation-Integration, and Sociopolitical Complexity on Sociopolitical Differentiation-Integration
Parameter estimates computed with a cascade model examining the effects of Military Technology Complexity, Military Technology Differentiation-Integration, and Sociopolitical Complexity on Sociopolitical Differentiation-Integration
Article
Limiting similarity theory (LST) and the principle of competitive exclusion (PCE) affirm that the degree of allowable niche overlap predicts the occurrence of tolerant coexistence between two or more biotic entities. Attribute variation reduces conflict, whereby two biological systems in direct competition for the same type of finite resources are incapable of peacefully existing under conditions of constant population increase. Complex biotic systems often face trade-offs regarding the allocation of relevant bioenergetics resources to different facets of their organization, further increasing the likelihood of attribute differentiation-integration. Evidence in support of the aforementioned perspectives has been found across biological entities, including human societies. Multilevel selection (MLS) theory provides a complementary framework for understanding the evolution of human sociopolitical systems, whereby within-group cooperation is sustained by ultrasocial institutions that can be employed for competition with other groups, such as in warfare. We gathered and analyzed data on sociopolitical complexity, military technologies, and differentiation-integration effects for 360 historical polities (13,000 BC-1895 AD) from the Equinox 2020 database. A cascade model detected a positive effect of Time on the evolution of military technologies. In turn, Military Technology negatively influenced the level of Military Technology Differentiation-Integration, indicating that some polities specialized in developing military technologies in response to local challenges, a finding consistent with LST and PCE. The model revealed that whereas Military Technology increases Sociopolitical Complexity, a result supportive of MLS, Military Technology Differentiation-Integration had a significant and negative influence on this criterion variable. Greater Sociopolitical Complexity also negatively influenced the degree of Sociopolitical Differentiation-Integration.
 
Article
Among four proposed origins of individualism-collectivism, modernization theory, rice versus wheat theory, climato-economic theory, and pathogen stress theory, the latter has gained more attention in cross-cultural and evolutionary psychology. Since the parasite stress theory of values and sociality makes a connection between infectious diseases and cultural orientations, it gained even more popularity during the COVID pandemic. But despite extensive research on parasite stress theory, it is not still clear what kind of infectious disease contributes more to the emergence of cultures, what are the possible mechanisms through which pathogenic threat gives rise to cultural systems, and how parasite stress might affect vertical vs. horizontal dimensions of individualism-collectivism. This review summarizes and integrates major findings of parasite stress theory related to individualism-collectivism and its closely related variables and discusses future directions that researchers can take to answer the remaining questions.
 
Mean discounting behaviour for naturally cycling (NC) women grouped by phase of the ovulatory cycle, for each of the 3 commodities (top row). The y-axis represents the probability of choosing immediate rewards as computed through Bayesian binomial regression. For example, a value of 0.2 equates to 20%. Error bars represent 95% Bayesian credible intervals. Distribution plots (middle, bottom rows) show posterior distributions over the effect size, Cohen’s h. Mean and 95% credible intervals are rounded to 2 significant figures
Mean discounting behaviour as a function of days since onset for naturally cycling (NC) and hormonal contraception (HC) groups, resulting from Bayesian quadratic binomial regression analyses. Solid lines represent posterior means, and the shaded regions represent 95% credible intervals in the mean probability of choosing the immediate reward. Note: the functions may not look exactly quadratic because the quadratic term is passed through the inverse logistic function to constrain probabilities between 0 and 1
Mean discounting behaviour as a function of fertility for naturally cycling (NC) and hormonal contraception (HC) groups, obtained from Bayesian binomial regression models. NC women were fitted with a slope and intercept model while HC women were fitted with an intercept only model, as fertility is held constant in the HC group
Article
Sexual desire, physical activity, economic choices and other behaviours fluctuate over the menstrual cycle. However, we have an incomplete understanding of how preferences for smaller sooner or larger later rewards (known as delay discounting) change over the menstrual cycle. In this pre-registered, cross-sectional study, Bayesian linear and quadratic binomial regression analyses provide compelling evidence that delay discounting does change over the menstrual cycle. Data from 203 naturally cycling women show increased discounting (preference for more immediate rewards) mid-cycle, which is at least partially driven by changes in fertility. This study provides evidence for a robust and broad-spectrum increase in delay discounting (Cohen’s h ranging from 0.1 to 0.4) around the fertile point in the menstrual cycle across multiple commodities (money, food, and sex). We also show, for the first time, that discounting changes over the menstrual cycle in a pseudo-control group of 99 women on hormonal contraception. Interestingly, such women increase their discounting of sex toward the end of the menstrual phase — possibly reflecting a prioritisation of bonding-related sexual activity before menstrual onset.
 
Article
Cellular sensitivity to testosterone is influenced by a gene located on the X chromosome called the androgen receptor gene (AR gene). Because males have just one X chromosome, whereas females have two, the functionality of the androgen receptor gene can be more precisely assessed in males. Male AR genes vary in terms of what is known as CAG repeats. The greater the number of repeats a male has, the less sensitive his cells tend to be to whatever testosterone is being produced (primarily by the testes). Studies have found substantial national variations in the average number of male AR CAG repeats. Of course, customs and laws regarding equal treatment of the sexes (gender equality) also vary a great deal between countries. The present study was undertaken to determine if national traditions of gender equality might be related to the national average number of AR CAG repeats among males. We hypothesized that the associations would be positive; i.e., the greater the number of average AR CAG repeats (and therefore the less cellular responsiveness to testosterone), the more a country's traditions and laws should favor gender equality. Even after introducing covariates, results provide substantial support for the hypothesis, thus suggesting that national variations in cultural practices might be genetically influenced.
 
Mediation model for intrasexual competitiveness explaining the link between global sociosexuality with same-sex indirect aggression
Mediation model for intrasexual competitiveness explaining the link between the desire facet of sociosexuality with same-sex indirect aggression
Article
The constellation of co-adapted traits that facilitate short-term mating promote the use of riskier and interpersonally antagonistic intrasexual competition tactics. Aggressive behavior can be used to vie against rivals for mates and resources that facilitate reproductive success; however, there is limited research regarding whether individual differences in a short-term mating orientation (i.e., unrestricted sociosexuality) are reliably associated with same-sex aggression, particularly indirect aggression. There is also some research suggesting that short-term mating tendencies are linked to inter-individual variability in the desire to compete with same-sex others for access to mates and reproductive resources (i.e., intrasexual competitiveness). We therefore speculated that intrasexual competitiveness might help to explain why those pursuing a short-term mating strategy may perpetrate more indirect aggression toward same-sex peers. In a sample of 290 Canadian heterosexual young adults, unrestricted sociosexuality positively predicted same-sex indirect aggression and intrasexual competitiveness, and intrasexual competitiveness mediated the positive link between unrestricted sociosexuality and indirect aggression. Exploratory analyses revealed that the desire facet of sociosexuality was driving the effect. These findings suggest that those with a short-term mating orientation, particularly those with unrestricted sociosexual desires, engage in more indirect aggression against same-sex peers, and that this association is, in part, explained by an inclination to be combative with same-sex rivals over social and mating resources.
 
Article
Friendship constitutes a human universal, with people across different times and places forming friendly relationships. Yet, people are selective in whom they befriend. The current research aimed to identify friendship preferences, that is, the traits that people find desirable or undesirable in a friend. More specifically, Study 1 employed open-ended questionnaires and identified 50 traits that participants preferred their friends to have, and 43 traits that they preferred their friends not to have. Study 2 employed a sample of 706 Greek-speaking participants and classified desirable traits into 10 broader factors; the most important one was being honest, followed by being ethical, pleasant, and available. Study 3 employed a sample of 865 Greek-speaking participants and classified undesirable traits into three broader factors. The most undesirable one was being dishonest, followed by being competitive and being impatient. In both studies, women tended to give higher scores than men. In addition, significant age effects were found for most factors in both studies.
 
Model results for Latter-day Saints
Model results for any religion
Article
There is solid evidence that human populations have been selecting against intelligence-related genetic variants since the mid to late 1800s. The selection is generally weak, but varies by ethnic group and sex. Since religious teachings usually include strong pro-natalist components, we investigated whether this might also affect the selection for intelligence among different religious groups. We found that Latter-day Saints in the USA show slightly positive selection for intelligence, whereas all other religious groups examined did not robustly differ from the average. We similarly found that conservatives, in general, show a weaker selection against intelligence than do liberals.
 
Article
The question of whether or not cranial hair affects perceptions of attractiveness, personality, career success, and other traits related to fitness for men in two populations was investigated in two experiments. Experiment 1 used a 2 (race) × 2 (cranial hair of man) design, and examined attractiveness, fitness, and socially desirable personality measures. Experiment 2 used a 2 (race) × 2 (cranial hair) design to determine perceived attractiveness, fitness-related traits, and the Big-5 dimensions of personality. Amount of cranial hair did not affect personality ratings on the dimensions of the Big-5 but did affect perceived socially desired aspects of personality (such as warmth, sophistication, kindness, etc.). In Experiment 1, the White man with hair received higher perceived attractiveness, personality, and fitness ratings than the bald White man, while no differences occurred for the Black men. For Experiment 2, when differences for amount of cranial hair occurred, the White man with hair and the Black man without hair received higher perceived fitness and career success ratings. These results are discussed in terms of prior research on male cranial hair.
 
Article
According to life history theory, as resources and energy are not infinite, individuals show behavioural and psychological variations on a fast-slow continuum associated to their life strategies. Fast strategies are associated with short-term gains and more opportunistic attitudes, while slow strategies are associated with delayed gratification and investment in long-term goals and plans. Art production, including music making, is a costly activity, demanding time and money for training, as well as an investment in a non-secure future. Hypothesizing that artistic production is an indicator of slow life strategy and should be more prevalent in safer and more affluent environments, we investigate whether music production is more prevalent and successful in higher socioeconomic environments. Across two studies, we investigated the effects of parasite stress and Human Development Index (HDI) on different indicators of metal music production (i.e. number of bands and labels) across the USA and the world. We found that HDI is a better predictor of metal music production than parasite stress. Our results suggest that individuals from harsher environments (including poorer health, education and wealth) are less likely to be able to afford resources to engage in artistic activities that include delayed gratifications.
 
A simple two-factor model
Violation of local independence and a case where the common interpretation of the manifest variables is jeopardized
A common pathway model
An independent pathways model
MIMIC models to be considered
Article
Recent research has advanced a socioecological theory to account for differences in the strengths of covariances among disparate personality measurements in different cultures. According to this socioecological complexity hypothesis, niche diversity is greater in more complex societies and this relaxes the covariances among personality traits (e.g., see Lukaszewski et al., 2017). While the socioecological complexity hypothesis is novel and interesting, we suggest that approaches used to test it thus far are conceptually and methodologically flawed. Accordingly, extant findings should be considered cautiously and not construed as evidence against alternative explanations for differences in personality or other behavioral trait covariances within or across countries. To advance the literature, here we review measurement issues that require attention in efforts to test the socioecological complexity hypothesis and then describe approaches that may aide researchers in overcoming them.
 
Between-mating strategy comparison: influence of male dater’s mating strategy on the displays of dependents on dating profiles; asterisks denote significant difference between comparison (ΔAICC ≥ 2). (a) Comparison of proportion of daters with dependent present on their profile; vertical lines denote 95% confidence interval. (b) Comparison of daters who displayed a dependent regarding the frequency of such displays; plot thickness proportional to density of corresponding y-values, diamonds denote mean, dots denote median
Asterisks denote significant difference between comparison, diamond denotes mean, dot denotes median. (a) Between-mating strategy comparison: influence of male dater’s mating strategy on the displays of dependent types on dating profiles. (b) Between-sex comparison: influence of sex regarding daters adopting a long-term mating strategy on the displays of dependent types on dating profiles
Between-sex comparison: influence of sex regarding daters adopting long-term mating strategies on the displays of dependents on dating profiles; asterisks denote significant difference between comparison (ΔAICC ≥ 2). (a) Comparison of proportion of daters with dependent present on their profile; vertical lines denote 95% confidence interval. (b) Comparison of daters who displayed a dependent regarding the frequency of such displays; plot thickness proportional to density of corresponding y-values, diamonds denote mean, dots denote median
Note. The influence of dater’s sex and mating strategy on the displays of dependents on POF profiles, asterisks denote significant difference between comparison, diamond denotes mean, dot denotes median. (a) Presence of dependent. (b) Frequency dependents were displayed.
Different letters denote significant difference between comparison, diamond denotes mean, dot denotes median. (a) Between-mating strategy comparison: influence of male dater’s mating strategy on the displays of dependent types on POF profiles. (b) Between-sex comparison: influence of sex regarding daters adopting a long-term mating strategy on the displays of dependent types on POF profiles.
Article
Sexual strategies theory indicates women prefer mates who show the ability and willingness to invest in a long-term mate due to asymmetries in obligate parental care of children. Consequently, women’s potential mates must show they can provide investment – especially when women are seeking a long-term mate. Investment may be exhibited through financial and social status, and the ability to care for a mate and any resulting offspring. Men who care for children and pets (hereafter “dependents”) are perceived as high-quality mates, given that dependents signal an ability to invest; however, no studies have examined how dependents are associated with short-term and long-term mating strategies. Here, online dating profiles were used to test the predictions that an interactive effect between sex and mating strategy will predict displays of dependents, with long-term mating strategy predicting for men but not women. Moreover, this pattern should hold for all dependent types and, due to relative asymmetries in required investment, differences will be strongest regarding displays of children and least in non-canine pets. As expected, men seeking long-term mates displayed dependents more than men seeking short-term mates, but both men and women seeking long-term mates displayed dependents similarly. This pattern was driven mostly by canines. These findings indicate that men adopting a long-term mating strategy display their investment capabilities more compared to those seeking short-term mates, which may be used to signal their mate value.
 
Models examining the moderating effects of expectations on the mediational relationship between life history indicators and psychopathology through dysfunctional schemas
Article
Although there have been recent advances in knowledge and thinking regarding life history conceptualizations of psychopathology, there is still a missing link. That is, although life history strategies may set the stage for the development of various psychopathologies, we believe there is a missing key factor in understanding individuals’ risk profiles of psychopathology. This study explored whether schemas and expectations might help differentiate between those who experience psychopathology and those who do not in a student and community sample. In the current cross-sectional study (N = 378), we examined the associations between life history indicators and experiences of anxiety, depression, obsessive–compulsive symptomatology, and substance use, as well as the possible mediating and moderating effects of schema and expectations on the associations, respectively. We found several significant mediational pathways with indicators of a faster life strategy predicting increased levels of dysfunctional schemas, and in turn predicting increased experiences of depression, anxiety, and obsessive–compulsive symptomatology, but not substance use. Moreover, although expectations did not significantly moderate the mediational pathways, expectations were a significant predictor of depression and anxiety, with those who reported having their expectations rarely met reporting increased experiences of depression and anxiety. Although this research is preliminary in nature, it has provided initial insight into how our schemas and expectations might play a role, alongside life history strategies, in better understanding individuals’ risk profiles for psychopathology.
 
Envy mediated the link between appearance comparison and negative gossip
Article
Physical attractiveness is a central component of women’s mate value. However, the extent to which women possess attractive physical traits varies between individuals, placing less attractive women at a mating disadvantage. Researchers have suggested that envy may have evolved as an emotion that promotes intrasexual competition in response to unfavorable social comparisons on important mate value traits, such as physical attractiveness. Previous research has shown that envy mediates links between unfavorable appearance comparisons and women’s intended appearance-enhancement behavior. In the current research, we extended this framework to examine the link between upward appearance comparisons and women’s intrasexual gossip. Women were assigned to either an appearance comparison or control advertisement rating task, and subsequently completed measures of state envy and gossip toward a same-sex rival. Results found that induced appearance comparisons predicted increased envy, which in turn predicted greater willingness to spread negative (but not positive) gossip about an attractive woman. Two cross-sectional survey studies (online supplement) replicated the model whereby more self-reported upward appearance comparisons predicted more self-reported gossip (Supplemental Study 1) and indirect aggression toward other women (Supplemental Study 2), and these links were mediated by dispositional envy. These results support the hypothesis that envy is an adaptation that promotes intrasexual competition using social aggression in response to unfavorable social comparisons on important mate value traits.
 
Article
This study examined how cyber and traditional aggression and victimization were differentially related to adolescent reports of using aggression to pursue evolutionarily relevant functions. To consider variations in the power balance between perpetrators and victims, the study examined bullying, in which the power of the perpetrator exceeded that of the victim, and adversarial aggression, in which the perpetrator had equal or less power than the victim. Participants included 379 adolescents, ages 11–14 (M = 12.86; SD = .84). As expected, cyberbullying and traditional bullying were consistently associated with proactive functions, including dominance, aggression deterrence and intrasexual competition (competitive), seeking status and mates (impression management), and enjoyment (sadistic), in line with the goal-directed nature of bullying. In contrast, cyber and traditional forms of adversarial aggression and victimization were associated with competitive and reactive functions (for boys only in cyber form), consistent with expectations that adversarial aggression would occur in the context of intrasexual competition. Relations with functions differed by gender only for cyber aggression. Cyberbullying was more strongly linked to competitive functions for girls, whereas adversarial cyber aggression related to competitive functions only for boys, and linked more strongly with reactive functions for girls, suggesting that girls may be more risk averse in their use of cyber aggression. In addition, traditional bullying was associated with both proactive and reactive motives, whereas cyberbullying was related only to proactive functions. The implications of differentiating the evolutionarily relevant aggressive functions associated with adolescents’ experiences of bullying and adversarial aggression are discussed.
 
concept of capital as a predictor of long-term reproductive success and inclusive fitness
Article
According to evolutionary theory, human cognition and behaviour are based on adaptations selected for their contribution to reproduction in the past, which in the present may result in differential reproductive success and inclusive fitness. Because this depiction is broad and human behaviour often separated from this ultimate outcome (e.g., increasing childlessness), evolutionary theory can only incompletely account for human everyday behaviour. Moreover, effects of most studied traits and characteristics on mating and reproductive success turned out not to be robust. In this article, an abstract descriptive level for evaluating human characteristics, behaviour, and outcomes is proposed, as a predictor of long-term reproductive success and fitness. Characteristics, behaviour, and outcomes are assessed in terms of attained and maintained capital, defined by more concrete (e.g., mating success, personality traits) and abstract (e.g., influence, received attention) facets, thus extending constructs like embodied capital and social capital theory, which focuses on resources embedded in social relationships. Situations are framed as opportunities to gain capital, and situational factors function as elicitors for gaining and evaluating capital. Combined capital facets should more robustly predict reproductive success and (theoretically) fitness than individual fitness predictors. Different ways of defining and testing these associations are outlined, including a method for empirically examining the psychometric utility of introducing a capital concept. Further theorising and empirical research should more precisely define capital and its facets, and test associations with (correlates of) reproductive success and fitness.
 
The Prophylactic Dehumanization Model
Effect of behavioral immune system (BIS) sensitivity on dehumanization of Chinese people, mediated by disgust. SDO, social conservatism, prejudice toward Chinese people, and dehumanization of ingroup (Americans) were entered as covariates. Values reflect standardized coefficients. ***p < .001
Effect of BIS sensitivity on anti-immigrant attitudes, mediated by disgust and dehumanization, and moderated by condition (0 = Control, 1 = Pathogen Threat). The dashed lines indicate moderated pathways. The value above each dashed line shows the effect for those in the pathogen threat condition, while the italicized value below each line shows the effect for those in the control condition. Values reflect unstandardized coefficients. ***p < .001
Article
The behavioral immune system (BIS) is an evolved psychological mechanism that motivates prophylactic avoidance of disease vectors by eliciting disgust. When felt toward social groups, disgust can dampen empathy and promote dehumanization. Therefore, we investigated whether the BIS facilitates the dehumanization of groups associated with disease by inspiring disgust toward them. An initial content analysis found that Nazi propaganda predominantly dehumanized Jews by portraying them as disease vectors or contaminants. This inspired three correlational studies supporting a Prophylactic Dehumanization Model in which the BIS predicted disgust toward disease-relevant outgroups, and this disgust in turn accounted for the dehumanization of these groups. In a final study, we found this process of prophylactic dehumanization had a downstream effect on increasing anti-immigrant attitudes during the COVID-19 pandemic. However, consistent with the evolutionary logic of a functionally flexible BIS, this effect only occurred when the threat of COVID-19 was salient. The implications of these results for the study of dehumanization and evolutionary theories of xenophobia are discussed. Supplementary information: The online version contains supplementary material available at 10.1007/s40806-021-00296-8.
 
Attractiveness as a long-term partner as a function of duration of previous relationship. Error bars are + / − 1 SEM
Attractiveness as a short-term partner as a function of duration of previous relationship, interval of past relationships, and participants’ experience of romantic relationships. Error bars are + / − 1 SEM
Attractiveness as a friend as a function of duration of previous relationship, interval of past relationships, and participants’ experience of romantic relationships. Error bars are + / − 1 SEM
Article
Mate-choice copying is a phenomenon whereby females assess the mate quality of males based on the mating decisions of other females. Previous studies demonstrated that the presence of a partner enhanced men’s attractiveness. Mate assessment is, however, error-prone, and the accepted male may turn out to be of poor quality after the relationship has progressed. This study extended the previous research by focusing on more reliable social information about male quality as a long-term partner: duration and interval of past relationships. Japanese female students (N = 201) were presented with a male profile containing information about past relationships, and they rated the target males as long- and short-term partners. The results confirm that information about a man’s long past relationship enhances the women’s desirability ratings for that man as a long-term partner. It was also found that a man with a long relationship was preferred by sexually inexperienced women, even in the short-term mating context, if the interval between the man’s past relationships was long. The study findings show that female mate choice is influenced by information about males’ past relationships, in addition to the information about male’s past partners discussed in previous studies. The finding for short-term mating suggests that it is used as a foothold for long-term relationships by females who may have lower mate value. The findings of this study add a new aspect to the non-independent mechanism of human mate choice.
 
The centipede game
The centipede game with Trivers-payoffs
The centipede game with Trivers-payoffs: average expected payoffs per game for the period (14 encounters) for a- and b-genotype players randomly playing X and Z, the number of a-genotype players in the group ranging from zero (0) to fifteen (15)
Article
Reciprocal altruism is a fact. There are many within-species and between-species examples of such strategic interaction. At the same time, reciprocal altruism would appear to be impossible. In deep evolutionary time, exceedingly small differences in costs will suffice to make the difference between life and death. Genotypes carrying extra costs will perish. How could individuals carrying extra altruistic costs survive? This study searches for the answer by looking at the mathematical features of the centipede game with what we call Trivers-payoffs. The notion refers to the reciprocally asymmetrical structure of costs and benefits between two players. There is an altruist individual X who gives significant benefits to another individual Z at a negligible cost to herself, getting similarly weighted favors back from Z. (1) When relative payoffs of the centipede game are defined as Trivers-payoffs, when the game is modeled in a finite population of players, and when strategies are depicted as genetically hard-wired operational instructions, the originally lone altruist mutation is capable of surviving and reproducing for quite some time, and (2) when the lone altruist mutation gets her first partner, changes in payoffs are dramatic. The altruist mutation begins to gain in payoffs and hence also in frequency.
 
Classification of diseases into ancestors and moderns categories and divided into two groups (chronic and acute) and categorized into four subgroups (chronic of high or low incidence and acute of high and low incidence)
Article
Human beings have an adaptive memory that adjusts to different threats in the environment; however, we know little about the factors that modulate this plasticity in memory. Using challenges related to disease threats as a research model, we investigated whether the regularity of occurrence and previous experience with diseases would be factors responsible for predicting memory performance. To test the hypothesis that information regarding diseases that affect with regularity over evolutionary time is better remembered, we grouped diseases into chronic and acute. To investigate the hypothesis that information about diseases that affect regularly in the current environment is better remembered, we grouped diseases into high-and low-incidence. Furthermore , to test the hypothesis that information about illnesses from previous experiences is better remembered, we grouped illnesses into experienced and unexperienced by the participants in this study. As an alternative hypothesis, we investigated whether the recall could be influenced by diseases that originated in ancestral environments or are simply explained by regularity and previous experience with diseases. For this purpose, we grouped the acute and chronic diseases into ancestral and modern. Information about illnesses was presented to university students through fictional stories, followed by an unexpected memory test to identify the best-remembered information. We found that information about diseases that affect regularly over evolutionary time (acute) and from previous experiences was remembered more, whereas ancestral and regular diseases in the current environment (high incidence) were remembered less. This was possibly because diseases that affect humans regularly over evolutionary time spawned greater earlier experiences, increasing people's perception of risk and facilitating its evoca-tion in memory. In addition, regular diseases in human evolutionary history may have generated greater selective pressure on memory, contributing to a better retention of information. Human beings have developed an adaptability to deal with different environmental adversities, favoring those challenges in memory that affect them regularly and from previous experiences and not necessarily those challenges that refer only to threats from ancestral environments.
 
Example item from a questionnaire
Article
One of the most important decisions an individual can make involves investing in a mating relationship. For women, the process of mate selection can be time-intensive and fraught with costs and dangers. However, these risks can be minimised by attending to relevant social information and modelling the mate choices of others. The propensity of imitating another’s mate choices is referred to as mate copying. Most research has focused on this behaviour in non-humans, but evidence of its existence in humans is emerging. The current study sought to determine conditions that modify a man’s desirability. The present study examined 267 women’s evaluations of men depicted in silhouetted images who varied in terms of their intentions for fatherhood and relationship history. Results showed that a man’s desirability as a long term mate was enhanced if he wished to become a father, and/or if he had a previous relationship experience, indicating he had been formerly chosen or preferred. These findings add to the existing body of knowledge on mate copying and attention to social information by demonstrating how women incorporate social learning and innate evolutionary predispositions to facilitate decision-making and behaviour relating to mate selection.
 
Article
Mothers’ fathers consistently invest more in their grandchildren than fathers’ mothers. This pattern was explained by Laham et al. in Personality and Social Psychology Bulletin , 31(1), 63-72. (2005) via the preferential investment hypothesis —the idea that fathers’ mothers invest less in grandchildren than mothers’ fathers because the former typically have more certain alternate investment outlets available. In two studies of prolific workers (combined N = 4086), we first failed to replicate the findings of Laham et al. and then successfully replicated them. In the combined sample, mothers’ fathers received more positive ratings than fathers’ mothers when participants had cousins through fathers’ sisters, but this difference between grandparents disappeared when participants did not have cousins through fathers’ sisters. We also found that people spent more time with their maternal and paternal grandparents to the degree that they were not maternal grandparents to someone else, which mediated the closer feelings.
 
Bar plots showing the sex-difference in frequency and intensity of comments on child resemblance. That is, when interviewees (The Participant) answered that both themselves and their sibling of the opposite sex (The Sibling) had made comments on resemblance, they were subsequently asked about who had made such comments most often and most intense. (A) Comments about one’s own child: In these cases, brothers (Males) reported that their sister (The Sibling) had commented most often and most intense, while sisters (Female) not found more proactive reporting among brothers (The Sibling). (B) Comments about their niece’s/nephew’s resemblance to their sibling: In these cases sisters (The Participant, Female) self-reported to have commented most often and most intense, wheras brothers (The Participant, Male) reported that their sibling sister commented most often and intence. Interviewees that reported no difference between themselves and the opposite sexed sibling are included in “Both the same.”
Article
The asymmetric grandparental investment in humans may ultimately be explained by the paternity uncertainty hypothesis. The proximate mechanisms leading to grandparental bias in investment in grandchildren are, however, unclear. In a study of 233 males and females with an opposite sexed sibling, we examined whether comments on resemblance regarding one’s own child, or one’s sibling’s child, changed in frequency after both siblings became parents. We found that comments among siblings on resemblance of children occurred more frequently after both became parents, compared to when only one of the siblings had children, suggesting that resemblance descriptions may become more important after both siblings have children. Furthermore, and in line with the suggestion that mothers may mentally exploit the alloparenting environment by holding a stronger belief about resemblance, brothers reported that their sisters commented on resemblance concerning their own child more often and more intensely. Additionally, sisters corroborated this finding by self-reporting that they were the most proactive during resemblance descriptions of their brothers’ child. Thus, sisters might, through more frequent voicing of stronger opinions on parent–child resemblance than their brothers, influence alloparents’ perception of resemblance to their children and thus influence alloparental investments.
 
Minimal outgroup categorization as a factor of target ethnicity and experimental condition. Error bars are SE
Article
Pathogen avoidance has been linked to biases against various groups of people, including ethnic outgroups. The present research explored how a non-hypothetical pathogen threat associated with a specific foreign ecology may differentially prompt biases against different ethnic groups. Two studies used an experimental design to examine how the salience of the COVID-19 threat (in early 2020, before COVID-19 was labeled a pandemic) affected perceptions of targets from different racial groups. Study 1 (N = 375; Prime Panels) found that participants in the COVID-19 threat condition, compared to those in the non-pathogen threat condition, perceived all social targets to be more contagious, with the effect being stronger for Asian targets relative to Latino, Black, and White targets. Study 2 (N = 167; undergraduate sample) found that participants in the COVID-19 threat condition, compared to those in the non-pathogen threat condition, were more likely to categorize Asian (but not Latino, Black, or White) targets as outgroup members in a modified minimal group paradigm. Data suggest that the patterns of biases prompted by pathogen avoidance may dynamically change depending on salient heuristic associations. Supplementary information: The online version contains supplementary material available at 10.1007/s40806-022-00321-4.
 
The Adapa Categories
The Tuxtla Categories
Concentric Circles Model for the Adapa Tablets and the Tuxtla Glyphs
Article
The purpose of this study was to examine how attitudes toward different nonhuman animal species (including emotional empathy, cognitive empathy, and harm avoidance) are shaped by the coevolutionary histories between the ancestors of contemporary humans and these different nonhuman animal species. We compared the explanatory power of alternative categorization frameworks for classifying attitudes toward animals across several cross-cultural samples (Arizona, California, Costa Rica, Spain, and Mexico). Analytical Approach 1 directly compared two alternative frameworks. Adapa categories were generated as purely functional ones based upon the ecological niches occupied by each species within the biotic community generated by human–nonhuman animal relations, and Tuxtla categories were generated as cognitive ones based upon the degrees of consciousness commonly ascribed to the constituent species. Analytical Approach 2 tested the alternative hypothesis that both categories were part of a general scheme organized into three superordinate categories reflecting concentric circles around our own, consistent with fitness interdependence theory. Results supported this alternative hypothesis. The concentric circles model (Kith & Kin Animals, Domesticated Animals, and Wild Animals) better explained empathy and harm avoidance scores, suggesting that attitudes toward specific animal species are partly shaped by which circles they fall into, the product of the coevolutionary relationship shared between them and humans.
 
Behavioral attitude SEM of psychopathic traits and demographics predicting investment domains. N = 254. For paths, only statistically significant standardized parameters are shown in figure. Non-statistically significant standardized parameters with 95% CI are mating behavioral attitude on age (0.076 [–0.077, 0.230], p = 0.328) and relationship status (0.134 [–0.035, 0.304], p = 0.121) and parental behavioral attitude on age (0.107 [–0.030, 0.245], p = 0.127) and relationship status (0.114 [–0.039, 0.268], p = 0.145). Somatic behavioral attitude on age (0.073 [–0.063, 0.209], p = 0.294) and parental status (0.056 [–0.106, 0.217], p = 0.497). Fit statistics: CFI = 0.90, RMSEA = 0.07. ***p < 0.001. **p < 0.01. *p < 0.05
Perception SEM of psychopathic traits and demographics predicting investment domains. N = 254. For paths, only statistically significant standardized parameters are shown in figure. Non-statistically significant standardized parameters with 95% CI are positive mating perception on age (0.110, [–0.041, 0.261], p = 0.153), relationship status (0.097 [–0.057, 0.251], p = 0.217), and parental status (–0.069 [–0.225, 0.086], p = 0.380); positive parental perception on age (–0.049 [–0.171, 0.073], p = 0.428), psychopathic traits (0.062 [–0.064, 0.189], p = 0.336), and relationship status (0.115 [–0.029, 0.260], p = 0.117); positive perception of direct somatic on age (0.041 [–0.103, 0.184], p = 0.578), psychopathic traits (0.024 [–0.019, 0.289], p = 0.710), relationship status (0.135 [–0.019, 0.289], p = 0.086), and parental status (0.027 [–0.128, 0.182], p = 0.731); and positive perception of indirect somatic on age (0.056 [–0.090, 0.202], p = 0.452) and parental status (0.054 [–0.100, 0.208], p = 0.491). Fit statistics: CFI = 0.95, RMSEA = 0.04. ***p < 0.001. **p < 0.01. *p < 0.05
Article
Psychopathic traits are sometimes viewed as an alternative reproductive strategy that prioritizes mating over parental investment , particularly in men. Two aspects of this research receiving less attention are (1) the inclusion of somatic investment, which refers to the growth and maintenance of oneself, and (2) measuring perceptions of investment domains in addition to behavior and attitude outcomes. In this study, we used a sample of 255 young adult men from MTurk (M age = 29.55, SD = 2.97) to examine how the three domains of investment (mating, parental, and somatic) relate to individual differences in men's psychopathic traits, relationship/parental status, and age using outcome measures of (1) behavioral attitudes and (2) perceptions of stimuli associated with each investment domain (e.g., attractive women's faces and cute infants). Results showed that while they were associated with being a parent, psychopathic traits were associated with higher mating and lower parental and somatic behavioral attitudes. Psychopathic traits were associated with negative perceptions of indirect somatic cues (e.g., working and forming friendships), positive perceptions of mating cues, and no relationship with perceptions of direct somatic (e.g., exercising) or parental cues. Our results agree with previous research but extend them by showing that while they engage in lower somatic behavior, men higher in psychopathic traits do not appear to have aversive reactions towards infant stimuli and are more likely to be parents themselves. We argue that these patterns are consistent with a parasitic parenting strategy that focuses on mating while depending on others to invest in their children.
 
Article
A great deal of research has focused on women’s attention to the physical and behavioral cues of potential romantic partners. Comparatively little work has investigated how these cues influence women’s sexual risk-taking. The current study investigated the relationship between women’s perceptions of various factors associated with their partner’s genetic or investment quality, and women’s risky sexual behaviors (i.e., behaviors that could lead to unintended pregnancy). This work also investigated the influence of estimated menstrual cycle phase using a between-subject design. Analyses failed to reveal menstrual cycle effects, but women reported a greater tendency to engage in risky sexual behaviors when they had more physically attractive partners and when they use sexual inducements as a mate retention strategy. Also, conception-risking behaviors occurred most often when the woman reported being more socially dominant and she reported being less upset by a potential pregnancy. Moreover, the self-reported likelihood that women would carry an unintended pregnancy to term with their partner was predicted by feeling less upset by a potential pregnancy, taking fewer social risks, religiosity, and by more favorable ratings of their partners’ masculinity. These results are discussed in line with evolutionary theory surrounding mate choice.
 
Sequential canonical analysis for the social biogeography of firearm suicides and homicides (Note: Effects shown only among the immediately successive criterion variables)
Article
The present research investigates relations among social-biogeographic factors (i.e., temperature, parasite burden, poverty rate, firearm possession rate, psychopathology rate, and estimated IQ), firearm homicide rate, and firearm suicide rate in each of the 50 states of the United States of America. Analysis of archival state-level data showed that local parasite burden strongly and positively predicted firearm homicide rate (sR = .58, p = < .0001). In contrast, both firearms possession rate (sR = −.18, p = .008) and State psychopathology rate (sR = −.34, p = < .0001) negatively predicted firearm homicide rate. In contrast, State psychopathology rate alone positively predicted suicide rate (sR = .42, p = < .0001). These results, which we discuss in terms of Thornhill’s and Fincher’s Parasite-Stress Model (2011), can be used to provide behavior-driven alternative models of behavior to guide political policy making and therapeutic interventions.
 
Example target strong (left) and weak bodies
Perceived effectiveness of strong and weak targets in protection and nurturance domains (with standard error bars)
Perceived likelihood of strong and weak targets to employ physical and verbal disciplinary tactics (with standard error bars)
Article
The selection of formidable male allies within coalitional settings is partially in the service of ensuring protection from physical threats for group members. Within these inferences could include specific judgments of formidable men as being effective at providing protection for their offspring, a judgment that could facilitate identification of prospective fathers who satisfy parenting goals. The current study sought to identify the specific value of men’s physical strength in shaping perceptions of their effectiveness in domains or protection and nurturance of offspring. Participants evaluated physically strong and weak in their effectiveness in these domains. Strong men were perceived as more effective in protecting their offspring than weak men, with this advantage corresponding with strong men being perceived as less effective in nurturance. We frame results from an affordance management framework considering the role of functional inferences shaping interpersonal preferences.
 
Examples of male and female targets connoting high (left) and low levels of psychopathy (right)
Examples of male and female targets connoting high (left) and low levels of narcissism (right)
Article
Despite the adaptive advantages of social affiliation in humans, the benefits of interpersonal contact are nonetheless bounded. The experience of crowding can emerge from an oversaturation of social affiliation, fostering avoidant behaviors and heightening vigilance toward interpersonal threats. Among these features indicative of threat includes facial structures connoting dark personality traits associated with a proclivity toward exploitative behavior. Despite the potential costs imposed by those exhibiting these features, individuals could nonetheless enjoy coalitional benefits from exploitative humans (i.e., protection). Two studies investigated whether crowding would foster aversion or interest toward facial structures connoting psychopathy and narcissism. Although crowd salience heightened tolerance for psychopathy (Study 1), providing evidence for a bodyguard hypothesis, narcissism was similarly aversive regardless of motivational state (Study 2). We frame results from an evolutionary perspective and provide tentative explanations for discrepant signal values through psychopathy and narcissism that could elicit disparate findings.
 
Examples of David statue with contrappostos − 2 on left, 0 in the middle, and + 2 on right
A screenshot of a computer’s rendering of the VR environment showing a Cicero statue and a displayed question
Article
A contrapposto pose, as exemplified by Michelangelo's David statue, is an asymmetric body posture known for its beauty and prevalence throughout the world of art. Past research has revealed that contrapposto poses are perceived to be more attractive than an upright, erect pose. Yet, this empirical work has only considered perceptions of the female body. There has been no systematic, empirical examination of the effect of male contrapposto poses on human perception. Therefore, across three studies differing in experimental methodology (2D vs. 3D stimuli), we investigated the effect of contrapposto poses in male statues on perceived attractiveness, masculinity, dominance, dynamicity, and naturalness. Four classical statues known for their contrapposto postures were manipulated in their degree of contrapposto, creating five stimuli in total for each statue (two decreased and 2 exaggerated from the original). In two studies, participants observed and rated 2D renderings of the statues. In another study, participants rated 3D statues while being immersed in a virtual reality environment. Results showed that 2D images varying in degrees of contrapposto poses did not affect the perception of the male statues. However, in the VR study, significant differences in ratings of attractiveness, dynamicity and masculinity were revealed. Specifically, an erect posture (decreased contrapposto) compared to exaggerated contrapposto poses increased the perception of attractiveness and masculinity but decreased the perception of dynamicity. Collectively, the results provide the first experimental evidence that variations in contrapposto poses in male models affect people's perception across a range of values, including on their attractiveness. We also provide evidence demonstrating the enhanced sensitivity of art perception within a VR environment.
 
Article
Relationships with genetic relatives have been extensively studied in the evolutionary social sciences, but affinal, i.e., in-laws, relationships have received much less attention. Yet, humans have extensive interactions with the kin of their mates, leading to many opportunities for cooperative and conflictual interactions with extended kinship networks. To contribute to the scholarship on affinal bonds, and particularly on perceptions of affinal conflict, we collected empirical data on cooperation and conflict among affines. Here, we report empirical evidence of self-reported cooperative and conflictual aspects in affinal relationships in a Western sample. US men and women both reported more conflict with mothers-in-law than with mothers, and mothers reported more conflict with their daughters-in-law than with their daughters. We discuss the implications of this work and directions for future research.
 
Mean ratings by target group, Study 1
Mean ratings by target group, Study 2
Mean ratings, centered within target group, and adjusted for baseline (the average person), Study 2
Article
We develop a general measure of stigmatization based on an evolutionary analysis of social exclusion (Kurzban & Leary, 2001)—the General Evolutionary Motives for Stigmatization (GEMS) scale. The measure includes subscales for contagion, dangerousness, dishonesty, lack of mental resources, and lack of material resources. Study 1 provided initial validity information in the form of “stigma profiles” for different disparaged groups. Study 2 replicated and extended those findings and highlighted the utility of including an “average person” baseline. Studies 1 and 2 further demonstrated that the GEMS, together with a humanitarianism-egalitarianism measure (Katz & Hass, 1988), can predict ambivalent feelings about stigmatized groups. Limitations and potential uses of the measure are discussed.
 
Simple slopes and 95% confidence bands of regression of slow LH strategy on the prevalence of infectious diseases at 1 SD above (A) and 1 SD below (B) the mean of fatality of infectious diseases
Simple slopes and 95% confidence bands of regression of COVID-19 behavioral control on the prevalence of infectious diseases at 1 SD above (A) and 1 SD below (B) the mean of fatality of infectious diseases
Article
The COVID-19 pandemic caught the world by surprise and raised many questions. One of the questions is whether infectious diseases indeed drive fast life history (LH) as the extent research suggests. This paper challenges this assumption and raises a different perspective. We argue that infectious diseases enact either slower or faster LH strategies and the related disease control behavior depending on disease severity. We tested and supported the theorization based on a sample of 662 adult residents drawn from all 32 provinces and administrative regions of mainland China. The findings help to broaden LH perspectives and to better understand unusual social phenomena arising from the COVID-19 pandemic.
 
The relation between fast HS and destructive responses at low, medium, and high levels of psychopathy trait/interactive values
Article
This study aimed to test the predictive power of individual differences in life history strategies (HS) on responses to conflicts in romantic relationships in a Brazilian sample (N = 251). Additionally, we investigated the moderator role of psychopathy and endorsement of basic values in the relationship between life HS and responses to conflicts. The results showed that fast HS (vs. slow HS) predicted less constructive responses to conflict. In addition, the psychopathy trait and interactive values moderated the relationship between the fast HS and destructive responses to conflicts: when medium and high on psychopathy, individuals employ more destructive responses. In turn, when medium and high on interactive values, individuals respond less destructively to conflict. Overall, these empirical findings are theoretically sound within evolutionary assumptions. In conclusion, the current results support that individual differences in life HS may predict relationship outcomes. In addition, this study adds to the literature on romantic relationships by connecting individual variables like personality and human values to evolutionary hypotheses for the understanding of romantic interactions.
 
Diagram representing the genetic-environmental pathways leading to the expression of parental and offspring phenotypes. Gene swarms are related to the parental genes that affect the offspring environment leading to the expression of the offspring phenotype
Article
Adverse Childhood Experiences (ACEs) are situated as the foundation of a six-tier pyramid, above which rests: (1) disrupted neurodevelopment; (2) social, emotional, and cognitive impairment; (3) adoption of health-risk behaviors; (4) disease, disability, and social problems; and (5) early death. ACEs purportedly initiate a causal sequence of negative developmental, behavioral, social, and cognitive outcomes, culminating in heightened mortality risk. Militating against this causal explanation, life history evolution is herein hypothesized to be the true foundation of any such pyramid. Subsuming ACEs within a life history framework has two broad implications: First, to some extent, ACEs are effectively changed from cause to correlate; second ACEs are seen as markers of strategic life history variation, not markers of dysfunction.
 
Descriptive statistics relating to all variables (study 1)
Descriptive statistics relating to all variables (study 2)
Article
Cyber dating abuse involves the use of electronic communication technology to direct abuse towards a romantic partner. Research has explored the perpetration of cyber dating abuse through an evolutionary lens, suggesting people use technology to perform mate retention tactics. Namely, previous research has found that mate value discrepancy and intrasexual competition predict the perpetration of cyber dating abuse. However, we do not yet know whether there is a direct relationship between cost-inflicting mate retention tactics and cyber dating abuse. Here, we directly explored whether cost-inflicting mate retention behaviours predict the perpetration of cyber dating abuse across two studies (study 1, n = 132; study 2, n = 124), finding strong support. We also explored the role of the Dark Triad in the perpetration of cyber dating abuse, and contrary to previous literature, we found no support. Our research furthers our understanding of the factors that drive cyber dating abuse from an evolutionary perspective.
 
Examples of feminized (left) and masculinized (right) versions of a male face image used in this study
The relationships between adverse childhood experiences and facial masculinity preference. The shaded areas around the regression line are 95% confidence intervals
Article
Life history theory posits that individuals with high early life stress tend to adopt a fast life history strategy and prefer short-term relationships. Evidence indicates that early life stress is associated with increased preference for sex-typical opposite-sex facial characteristics in heterosexual men and women. Indirect evidence suggests that early life stress might also affect facial preference in gay men; however, this has not been directly tested. This study aimed to examine whether early life stress is related to facial masculinity preference in gay men in China. Two hundred and ninety gay men completed self-reported measures of facial masculinity preference and early life stress (i.e., childhood socioeconomic status (SES), parental investment, abuse, and household dysfunction). The results revealed that adverse childhood experiences (childhood abuse and household dysfunction) were associated with facial masculinity preference. Individuals who had adverse childhood experiences were more likely to prefer masculinized male faces. There were no significant associations between facial masculinity preference and SES or parental investment. The findings indicated that life history strategy is associated with partner choice in gay men.
 
Interaction between genetic relatedness and duration of co-residence on frequency of sibling conflict
Interaction between genetic relatedness and duration of co-residence on intensity of sibling conflict
Article
While siblings can be close allies, they can also be significant competitors. They are also family members that are typically with us for most of our lives. Research has raised questions about the factors shaping sibling relationships, and an adaptationist perspective would predict a role for a number of factors including sex, genetic relatedness, and childhood co-residence. Recent work has highlighted sex differences with regard to conflict and emotional closeness, greater conflict among full-siblings than half-siblings, and a role for co-residence in increasing sibling altruism. This study examines levels of both sibling conflict and sibling cooperation as a function of respondent sex, sex of sibling, birth interval (or absolute age difference), co-residence, and relatedness. Results indicate that sibling conflict and cooperation may not be shaped by the same set of factors. Sibling conflict was predicted by own sex, sex of sibling, birth interval, duration of co-residence, and the degree of relatedness. Greater levels of conflict were reported by sisters, those closer in age, those who have co-resided longer, and full-siblings compared to half-siblings. However, sibling prosocialness was only predicted by sex and relatedness with females and full siblings reporting greater levels of sibling prosocialness. More research investigating patterns of conflict and cooperation within families using more ecologically valid cues are necessary to determine whether the two are operating under the same mechanism, sensitive to the same cues, or are, indeed, operating under different mechanisms.
 
Article
Mate copying (MC) refers to the increased probability of preferring an individual as a mate, as a result of them having been chosen by same-sex peers previously. How changes in the world, such as the increased use of social networking sites, affect MC has not received much attention. Participants were shown photographs of opposite-sex target individuals, and told that the profiles had a high, moderate, or low number of opposite-sex Facebook friends. A two-way analysis of variance (ANOVA) indicated that opposite-sex profiles were considered the most desirable when no information was given about thegender distribution of their Facebook friends. Both men and women found opposite-sex profiles to be least desirable when they had a high number of opposite-sex friends. The findings contribute to the literature by providing further information about the mate selection processes for both sexes, and how social networking sites have changed the way interpersonal relationships are formed.
 
Simple slope plot for the moderating role of mate value in the relationship between the Dark Triad traits and jealousy
Simple slopes plot for the moderating role of short-term mating in the relationship between psychopathy and behavioral jealousy
Article
The motivation to mate is a universal motive for all sexually dimorphic species, of which humans belong, that facilitates reproductive success. Jealousy is a universal emotion that is adaptive in the context of mate retention. We tested the relationship between the Dark Triad traits and jealousy as well as the moderating effect of mate value (study 1; N = 441) and mating orientation (study 2; N = 298) on the association between the Dark Triad traits and jealousy. We found that perceived mate value moderated the relationship between the Dark Triad traits and jealousy. As such, people high on the Dark Triad traits were more jealous if they had high mate value. Further, mating orientation moderated the relationship between psychopathy and romantic jealousy. Individuals high on psychopathy that were oriented to long-term mating were more jealous compared to individuals high on psychopathy but oriented to short-term mating.
 
Article
Children’s nighttime fear is hypothesized as a cognitive relict reflecting a long history of natural selection for anticipating the direction of nighttime predatory attacks on the presumed human ancestor, Australopithecus afarensis , whose small-bodied females nesting in trees would have anticipated predatory attacks from below. Heavier males nesting on the ground would have anticipated nighttime predatory attacks from their sides. Previous research on preschool children and adults supports this cognitive-relict hypothesis by showing developmental consistencies in their remembrances of the location of a “scary thing” relative to their beds. The current study expands this research by investigating whether nighttime fear in childhood, including the effect of parental threats to behave, influenced adult spatial fears in different biotic and abiotic situations. A 25-item questionnaire employing ordinal scales was given to 474 foreign-born Vietnamese and ethnic Chinese adults living in the USA. Univariate analyses of adult remembrances of childhood indicated that females were more fearful of something scary below their beds than males. To examine the influence of childhood nighttime fear on adult fears, exploratory factor analyses supported three factors: (1) indeterminate agents, indicated something scary under the bed, the difficulty locating unspecific threats, and the brief appearances of large apparitions; (2) environmental uncertainty, indicated by potential encounters with unseen animate threats; (3) predictable animals, as the relative comfort of viewing animals in zoo exhibits. Using structural equation modeling, the results suggest that childhood nighttime fear influenced only the latent variable, indeterminate agents, in both groups via the mediating variable, parental threats.
 
Article
People frequently adopt extra-pair mating strategies, which could be potentially harmful for their legitimate partners. In order to protect themselves from the costs of cheating, people need first to detect infidelity, and for this purpose, they employ specific infidelity-detection strategies. By using a combination of qualitative research methods, we identified 47 acts that people perform in order to detect their partners’ infidelity. Using quantitative methods, we classified these acts into six broader strategies for detecting infidelity. Participants indicated that they were more likely to employ the “Observe changes in her/his behavior,” followed by the “Ask and observe her/his reactions,” and the “Check where she/he is” strategies. Almost 58% of the participants indicated that they would use three or more strategies in order to detect their partners’ infidelity. We also found that higher scorers in Machiavellianism and psychopathy were more likely to employ the identified strategies than lower scorers. In addition, sex and age effects were found for most strategies.
 
Frequency of conjunction errors for both long-term and short-tem mating strategy questions (Study 1)
Frequency of conjunction errors for both long-term and short-tem mating strategy questions (Study 2)
Frequency of conjunction errors for long-term tem mating strategy questions for religious vs. nonreligious participants (Study 3)
Article
Recent evidence suggests that the adoption of religious beliefs and values may be used strategically to enhance long-term mating strategies, which implies an intuitive connection between differences in mating strategy and religiosity. This connection was investigated in a two-part primary hypothesis: perception of long-term mating strategies should increase association with religiosity and decrease association with nonreligiosity, while perception of short-term mating strategies should decrease association with religiosity and increase association with nonreligiosity. This was studied using a novel methodology of developing two mating strategy narratives (short-term vs. long-term) constructed from a preestablished measure and exploiting the tendency to use the representativeness heuristic and conjunction error to study the intuitive links between mating strategies and religiosity. Study 1 served as a pilot study using undergraduates and confirmed the primary hypothesis. Studies 2 and 3 expanded on study 1 by using a more representative sample through a larger Qualtrics panel of participants more closely matched to the general US population and also added the variables of participant religiosity and gender to the analysis. These studies not only confirmed the primary hypothesis but also demonstrated that how religiosity is described has an effect on whether or not it is associated with long-term strategies. Gender did not have an effect on the association between mating strategy and religiosity, but in study 3, nonreligious individuals did not associate long-term mating strategies with religiosity.
 
Example high-(left) and low-fWHR targets
Perceived capability for high-and low-fWHR targets to experience primary and secondary emotions (with standard error bars)
Mean assessments of primary and secondary emotion capa- bilities (and standard deviations)
Mediation pathways for formidability assessments and perceived mental distress on suicide assessments and medication recommendations. We conducted an item-level analysis for each of the 14 target emotions to identify potential granularity in the emotions for which high- and low-fWHR targets appear most capable of experiencing. We set our significance level to α = 0.001, given the number of comparisons we made. Paired-sample t-tests indicated that low-fWHR targets were perceived as significantly more capable of experiencing every emotion compared to high-fWHR targets, except for desire, repentance, and anger. High-fWHR targets were perceived as more capable of anger than low-fWHR targets. However, because of the overall reliability these items exhibited across both categories, we found it prudent to consider these capabilities as singular constructs of primary and secondary emotions. Results from this analysis are available as a supplementary file in the OSF link
Article
Humans infer men’s formidability through their facial width-to-height ratio (fWHR), subsequently eliciting perceptions of men’s capability to engage in aggressive physical conflict. Inferring formidable men as being particularly resistant to mental distress from physical conflict may pose downstream consequences, such as biasing mental health assessments that impede optimal treatment recommendations. Participants assessed potential mental distress of hypothetical military service members who varied in fWHR and indicated their willingness to assess and treat these symptoms. Formidable men were inferred as mentally tough, further biasing perceptions of them as not experiencing mental distress and not receiving subsequent care. We further replicated infrahumanization effects surrounding formidable men demonstrating individuals perceive them as less capable of feeling complex emotions, though treatment recommendations were driven by mental toughness perceptions rather than infrahumanization. Results are framed from an evolutionary perspective of affordance judgments. We discuss translational implications for clinical mental health.
 
Percentage of women and of men in the various ranks. The percentages refer to the percentage within each sex in a given rank. Numbers in white represent sample sizes in each rank
Police rank and height for men and women. The grey dots are the raw data points. The black dot and error bars represent the mean and 95% confidence interval. The black dashed line represents the mean height in the sample for that sex. Numbers in grey represent sample sizes per rank
Article
This study among 725 male and 247 female police officers from The Netherlands examined the association between self-reported height and occupational rank from the perspective of sexual selection. Male and female police officers were taller than the average population. A larger percentage of women than of men was found in the lowest ranks, but in the leadership positions, there was a similar percentage of women as of men. Overall, but especially among women, height was linearly associated with occupational rank: the taller one was, the higher one’s rank. These effects were independent of educational level and age. The implications for evolutionary theorizing from the perspective of sexual selection on the effect of tallness on status and dominance among women are discussed.
 
Support for Travel Bans on High Risk Nations (China and Italy) between Conditions
Article
Given the persistent threat posed by infectious disease throughout human history, people have a sophisticated suite of cognitive and behavioral strategies designed to mitigate exposure to disease vectors. Previous research suggests that one such strategy is avoidance of unfamiliar outgroup members. We thus examined the relationship between dispositional worry about disease and support for COVID-19-related travel bans across three preregistered studies (N = 764) conducted at the outset of the pandemic in the United States and Singapore. Americans higher in Perceived Infectability were more supportive of travel bans, whereas Singaporeans higher in Germ Aversion were more supportive of travel bans. In Study 2, priming saliency of the pandemic increased support for travel bans from high (but not low) pandemic-risk countries. This prime did not increase general xenophobia. These results are consistent with threat-specific perspectives of outgroup avoidance, and provide an ecologically-valid test of the implications of perceived disease threat for policy-related attitudes and decision-making. Supplementary information: The online version contains supplementary material available at 10.1007/s40806-021-00283-z.
 
Article
While a great deal of psychological research has been conducted on sex-specific mate choice preferences, relatively little attention has been directed toward how heterosexual men and women solicit short-term sexual partners, and which acts are perceived to be the most effective. The present research relied on an act nomination methodology with the goal of determining which actions are used by men and women to solicit a short-term “hook-up” partner (study 1) and then determine which of these actions are perceived as most effective by men and women (study 2). Using sexual strategy theory, we hypothesized that actions that suggest sexual access would be nominated most often by women whereas actions that suggest a willingness to commit were expected to be nominated most often by men. Additionally, men and women were predicted to rate actions by men that suggest a willingness to commit as most effective and actions by women that suggest sexual access as most effective. The results were consistent with these hypotheses. These findings are discussed in the context of both short- and long-term mating strategies and mate solicitation. The relationship between motivation, sexual strategies, and sexual behavior are examined, along with the need for research on the hookup tactics and motivations of self-identifying gay, lesbian, and bisexual individuals.
 
Article
David F. Bjorklund, Professor of Psychology at Florida Atlantic University, has influentially contributed to the development of evolutionary developmental psychology as a field. The general argument of Bjorklund in How Children Invented Humanity: The Role of Development in Human Evolution is that ontogeny has shaped the evolution of humans.
 
Article
A significant open issue in the field of comparative psychology is the apparent inability to reconcile the existence of ‘little g’ (general intelligence) common factor variance among cognitive performance data involving individuals within species, with the existence of higher-level ‘Big G’ factor variance among species-level cognitive aggregates. Here, using a cognitive individual differences dataset of three Lemur species (grey mouse lemur; Microcebus murinus, ruffed lemur, Varecia variegata, and ring-tailed lemur, Lemur catta), we replicate a previously published solution to this problem. This is based on the hypothesis that there does exist g or g-like variance that is predictive of species differences, but that many of the measures employed in cross-species cognition tests impose floor or ceiling effects on one or more of the species being compared. These will obscure the alignment between g and G when individuals of multiple species are compared. An iterative latent variable moderation model is used, whereby sequentially removing subtests based on lowest coefficient of variance (CV) increases the degree to which g-loadings moderate the species differences among the remaining subtest pool. The correlation between moderator effect magnitude and rising CV across twelve iterations (from fourteen to three subtests) ranges from .710 to .854 based on which pairs of species are being compared. This result is consistent with the expectation that across species, g is highly predictive of species differences (and thus, g and G are one and the same), although significant ‘modular’ differences doubtlessly also exist. Predictions stemming from these observations are outlined using simulations. Finally, the implication of these findings for constructing trans-species valid measures of g and ‘IQ’ for use in future research (such as trans-species GWAS) is discussed.
 
Top-cited authors
Mitch Brown
  • University of Arkansas
Menelaos Apostolou
  • University of Nicosia
Michael Anthony Woodley of Menie
Todd K Shackelford
  • Oakland University
Thomas Pollet
  • Northumbria University