Evolution and Human Behavior最新文献

The Reproductive Compensation (RC) hypothesis and the Differential Allocation (DA) hypothesis predict that parents who mate under constraint will either increase or decrease, respectively, their reproductive effort and investment in offspring. One possible type of mate choice constraint in humans is arranged marriage in which parents or others choose mates. To test the RC and DA hypotheses in humans, we examine whether there are differences in parental investment between women in arranged marriages and those in self-choice marriages using data from the Indonesian Family Life Survey (n = 8393). Marriage type does not significantly correlate with parental investment except for fertility outcomes where women in self-choice marriages had more live births, living children, and greater marital fertility than woman in arranged marriages. Our findings better support the DA hypothesis than the RC hypothesis. We conclude that, like many other species, free mate choice is associated with increased reproductive success in this sample of humans.

Individuals consistently report preferring humour in a romantic partner; but it is unclear why. The ‘fitness indictor hypothesis’ proposes that attraction to humour evolved because it is an indicator of genetic fitness. Studies testing predictions from this hypothesis, mostly based on stated preferences regarding a hypothetical ideal partner or on artificial tasks or scenarios, have so far yielded conflicting evidence. Here, we assessed a sample of 554 participants' (291 women) stated preferences for various traits including humour production and receptiveness, and their revealed preferences for the same traits through speed dates (i.e. a naturalistic, face-to-face setting). Dates were audio-recorded for a subset of 350 participants (188 women), enabling additional assessment of revealed preferences based on an objective measure of humour in the form of laughter frequency. We tested the predictions that 1) humour is an attractive trait, and 2) men are more attracted to humour receptivity compared to women, and women are more attracted to humour production compared to men. Stated preferences from men and women largely replicated those found in the existing literature and are consistent with the fitness indicator hypothesis. Results from revealed preferences found a main effect of funniness on ratings of overall partner attractiveness, but there was no significant effect of laughter on attractiveness. Revealed preferences, using both funniness ratings and laughter, also found no main effect of humour receptivity on overall attractiveness. Finally, we observed no sex differences in the effects of humour production and humour receptivity, as measured by both funniness ratings and laughter, on ratings of overall attractiveness.

Mate choice is a fitness-relevant decision, that can be informed by the mate choices of others. Such mate-choice copying has been documented across multiple species, including humans. However, so has copying in many other contexts. As such, the exent to which mate-choice copying is underpinned by the same psychological mechanisms as copying in other contexts remains unclear. To test these hypotheses, we conducted an online experiment (recruiting from M-Turk, n = 165) to examine whether human mate choice copying is prestige and/or conformist biased (both of which are documented in other domains), and whether it differs between men and women. If mate choice copying is underpinned by broad-context mechanisms, we predict it will be similar in men and women, with both groups also exhibiting prestige-biased and conformist transmission. Our results match these predictions, exhibiting no evidence of a difference in mate-choice copying between men and women, and evidence of prestige-biased and conformist transmission. These results suggest that mate choice copying is the product of adaptive, broad-context copying mechanisms.

Life history theory applied to human development stipulates that humans have evolved to detect and encode information from the early developmental environment that entrain coordinated development pathways. One possible mechanism is epigenetic age acceleration but few studies have prospectively examined associations between epigenetic aging and life-history related phenotypes. The purpose of this study was to examine the relations between epigenetic age acceleration when children were age 7 years and indices of reproductive development during adolescence using a sample of N = 512 youth from the Avon Longitudinal Study of Parents and Children (ALSPAC). A path model was used to test direct and indirect associations between epigenetic age acceleration and age at menarche (AAM), age at first sex, and lifetime and past year sexual partner number. Results showed epigenetic age acceleration was directly associated with earlier age at first sex and increased sexual partner number. There were further indirect associations with sexual partner number via age at first sex. Epigenetic age acceleration was not associated with AAM. Follow-up analyses to determine if aspects of the early developmental environment were associated with age acceleration were null. Implications for life history theory and the need for additional research are discussed.

Gender inequalities in status and prestige are common across many populations, but while considerable attention has been paid to understanding the drivers of men's status, the causes and consequences of women's status have received scant attention, particularly outside industrialized contexts. We combine demographic, health and dyadic rating data from an endogamous community to show that women of higher status have improved outcomes for themselves and their children. We find perceptions of generosity, intelligence, and respectfulness best predict women's status. Women of greater status marry higher quality partners and have children with better growth outcomes, results similar to those found for men across cultures, but rarely demonstrated in women. The results suggest women's status can be an important driver of fitness-related outcomes, and should be considered alongside men's status in evolutionary studies.

Within evolutionary psychology, a dominant assumption is that adaptive variation in fast versus slow life history strategies centrally includes variation in sociosexual orientations. Fast reproductive strategies—prioritizing current reproduction and high number of low-quality offspring—are purportedly facilitated by short-term, uncommitted sexual relationships with multiple partners and investing little in resulting offspring (a high mating effort, low parental effort strategy). Slow strategies—of producing few, high-quality offspring—purportedly entails having few lifetime sexual partners and forming long-term, committed pair-bonds in which both parents invest heavily in offspring (a high parental effort, low mating effort strategy). Notably, proposals for individual variation in human life history strategies are inspired by cross-species evidence on covariation of traits related to reproduction and longevity. However, examination of evidence across mammals, birds, and primates reveals that variations in mating versus parental effort are not central to the interspecies dimensions of fast-slow strategies. Variations in pair-bonding and biparental care likewise do not map onto the fast-slow continuum or offspring quantity versus quality dimension. Indeed, in human foraging groups, male provisioning appears to increase offspring quantity. For several reasons, sex with multiple partners does not promote women's fertility rate. Alternative selection pressures are more likely to have led to adaptive variation in human mating strategies.