Evolutionary Psychology

Kruger, Daniel J.; Schlemmer, Erin

2009 Evolutionary Psychology

doi: 10.1177/147470490900700210

If marriage markets were only subject to the influences of numerical supply and demand, one would expect that the scarcer sex in a population would have a greater proportion married. Previous research has demonstrated that when males are scarce, they are actually less likely to be married, presumably because their market scarcity enhances their short term mating success and decreases incentives for commitment. However, males in modern societies appear to shift from mating effort to parental investment across the life course. Also, women preferentially value indicators of phenotypic quality for short term relationships, and these signals may be increasingly difficult to display with progressive physiological senescence. We predicted that men in low sex ratio populations would use market scarcity to their advantage for mating effort when young, but would shift towards commitment strategies when older. Data from the 50 largest Metropolitan Statistical Areas in the USA confirmed that a female biased sex ratio was associated with a lower proportion of men married between ages 20 and 29, but a higher proportion of men married between ages 35 and 74.

Moroschan, Gail; Hurd, Peter L.; Nicoladis, Elena

2009 Evolutionary Psychology

doi: 10.1177/147470490900700201

Evolutionary psychologists have argued that the emergence of language was associated with reducing direct physical aggression and easing social functioning in small groups. If this is so, then males should use verbal or indirect aggression more frequently than females since they engage in more direct aggression. A recent study found no significant differences between men and women's self-reports of indirect aggression in a U.K. sample. We administered the same questionnaire to 175 male and 311 female Canadian university students. Men in this population reported using indirect aggression more frequently than women. The Canadian participants generally reported using indirect aggression less frequently than the U.K. study sample did, particularly the women. These results suggest that there are cultural differences in adults' frequency of use of indirect aggression. We review a number of possible reasons to account for these different results.

Fitzgerald, Carey J.; Colarelli, Stephen M.

2009 Evolutionary Psychology

doi: 10.1177/147470490900700207

We examined how different types of reproductive limitations — functional (schizoid personality disorder and schizophrenia), physical (malnutrition), and sexual (bisexuality and homosexuality) — influenced altruistic intentions toward hypothetical target individuals of differing degrees of relatedness (r = 0, .25, and .50). Participants were 312 undergraduate students who completed a questionnaire on altruism toward hypothetical friends, half-siblings, and siblings with these different types of reproductive limitations. Genetic relatedness and reproductive limitations did not influence altruistic decision-making when the cost of altruism was low but did as the cost of altruism increased, with participants being more likely to help a sibling over a half-sibling and a half-sibling over a friend. Participants also indicated they were more likely to help a healthy (control) person over people with a reproductive limitation. Of the three types of reproductive limitations, functional limitations had the strongest effect on altruistic decision-making, indicating that people were less likely to help those who exhibit abnormal social behavior.

Gummerum, Michaela; Takezawa, Masanori; Keller, Monika

2009 Evolutionary Psychology

doi: 10.1177/147470490900700212

Evolutionary theories of altruism have suggested that reciprocal exchanges and ingroup favoritism have been important strategies leading to the evolution of altruistic behavior among strangers. This study investigates whether minimal information about an interaction partner's membership in a trivial social group affects the allocations of adults and children in dictator game, reciprocity in a sequential prisoner's dilemma, and altruistic punishment in a third-party punishment game. In all, 155 adults and 157 students from second and sixth grade played these three economic games in either an ingroup, outgroup, or neutral condition. Adults and sixth-grade children allocated more to ingroup than to outgroup receivers in the dictator game, and adults punished ingroup non-cooperators more in the third-party punishment game than outgroup non-cooperators. When additional information about the other player's past behavior was presented, adults reciprocated equally with ingroup, outgroup, and neutral players, whereas children from sixth grade reciprocated more with ingroup and neutral than with outgroup players. Overall, the results of this study support the importance of group membership and reciprocity for adults' and older elementary school children's altruistic behavior. For younger elementary school children, however, reciprocity and group membership do not serve as salient social information that influence their altruistic behavior.

Liddle, James R.; Shackelford, Todd K.

2009 Evolutionary Psychology

doi: 10.1177/147470490900700211

Bell, Raoul; Buchner, Axel

2009 Evolutionary Psychology

doi: 10.1177/147470490900700213

The present experiment shows that source memory for names associated with a history of cheating is better than source memory for names associated with irrelevant or trustworthy behavior, whereas old-new discrimination is not affected by whether a name was associated with cheating. This data pattern closely replicates findings obtained in previous experiments using facial stimuli, thus demonstrating that enhanced source memory for cheaters is not due to a cheater-detection module closely tied to the face processing system, but is rather due to a more general bias towards remembering the source of information associated with cheating.

Del Giudice, Marco

2009 Evolutionary Psychology

doi: 10.1177/147470490900700209

A comprehensive evolutionary theory of sex differences will benefit from an accurate assessment of their magnitude across different psychological domains. This article shows that mainstream research has severely underestimated the magnitude of psychological sex differences; the reason lies in the common practice of measuring multidimensional differences one dimension at a time, without integrating them into a proper multivariate effect size (ES). Employing the Mahalanobis distance D (the multivariate generalization of Cohen's d) results in more accurate, and predictably larger, estimates of overall sex differences in multidimensional constructs. Two real-world examples are presented: (1) In a published dataset on Big Five personality traits, sex differences on individual scales averaged d = .27, a typical ES conventionally regarded as “small.” However, the overall difference was D = .84 (disattenuated D = .98), implying considerable statistical separation between male and female distributions. (2) In a recent meta-analytic summary of sex differences in aggression, the individual ESs averaged d = .34. However, the overall difference was estimated at D = .75 – .80 (disattenuated D = .89–1.01). In many psychological domains, sex differences may be substantially larger than previously acknowledged.

Pawlowski, Boguslaw

2009 Evolutionary Psychology

doi: 10.1177/147470490900700202

Geher, Glenn

2009 Evolutionary Psychology

doi: 10.1177/147470490900700214

This research focuses on mating-relevant judgments within an evolutionary framework. Using a methodology that employs personal ads as stimuli, the current study tested predictions from Error Management Theory (Haselton and Buss, 2000) suggesting that males will oversexualize females' desires, showing a tendency to think women are more interested in unrestricted sexual encounters than is warranted. This work further tested whether women's judgments represent an oversexualization of males' desires, which may reflect the adaptive bias of commitment skepticism. This work also tested whether overall accuracy in these judgments was sex-differentiated. 481 young male and female heterosexual adults judged which personal ads (written by opposite-sex individuals) were most desirable as short and long-term mates. All participants then engaged in a cross-sex mind-reading task by guessing which ads were most strongly endorsed by opposite-sex individuals. Males were more accurate than females in guessing long-term desires; females were more accurate than males in guessing short-term desires. Male oversexualization of females' desires was not pronounced in these data. However, female oversexualization of males' was quite pronounced for both short and long-term judgments. Discussion addresses how the sexes may be tuned into different strategic mating cues in the domain of cross-sex mind-reading in addition to how oversexualization of opposite-sex judgments may serve discrete adaptive functions across the sexes.

Camilleri, Joseph A.; Quinsey, Vernon L.

2009 Evolutionary Psychology

doi: 10.1177/147470490900700203

Evolutionary theory has informed the investigation of male sexual coercion but has seldom been applied to the analysis of sexual coercion within established couples. The cuckoldry risk hypothesis, that sexual coercion is a male tactic used to reduce the risk of extrapair paternity, was tested in two studies. In a community sample, indirect cues of infidelity predicted male propensity for sexual coaxing in the relationship, and direct cues predicted propensity for sexual coercion. In the forensic sample, we found that most partner rapists experienced cuckoldry risk prior to committing their offence and experienced more types of cuckoldry risk events than non-sexual partner assaulters. These findings suggest that cuckoldry risk influences male sexual coercion in established sexual relationships.