| 1. |
- Kaar, P, et al.
(författare)
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Sexual conflict and remarriage in preindustrial human populations: Causes and fitness consequences
- 1998
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Ingår i: Evolution and human behavior. - 1090-5138 .- 1879-0607. ; 19:3, s. 139-151
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Tidskriftsartikel (refereegranskat)abstract
- Sexual conflict is said to occur when one mating partner has an opportunity to increase its fitness at the cost of the other. We analyzed the effect of remarriage on lifetime reproductive success (LRS) in three preindustrial (1700–1900) socially monogamous Sami populations. In all populations, ever-married women’s age-specific mortality rates exceeded those of ever-married men during reproductive years. After the death of a spouse, men had a higher probability of remarriage than did women of the same age. Remarried men had a higher LRS than men who married only once, but this was not true for women. The higher LRS of the twice-married men was probably due to their longer (+5 years; p < .05) reproductive lifespan (RLS) as compared to once-married men. There was no difference in the RLS of women who married once or twice. These results suggest the sexual conflict in these populations was won by men because women paid a higher cost from reproduction (i.e., reduced survival), and men were able to remarry more often than women, thereby realizing more of their higher reproductive potential. Consequently, serial monogamy seem to have been an important male reproductive strategy in these historical populations.
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| 2. |
- Anikin, Andrey
(författare)
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Why do people make noises in bed?
- 2024
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Ingår i: Evolution and Human Behavior. - 1090-5138. ; 45:2, s. 183-192
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Tidskriftsartikel (refereegranskat)abstract
- Many primates produce copulation calls, but we have surprisingly little data on what human sex sounds like. I present 34 h of audio recordings from 2239 authentic sexual episodes shared online. These include partnered sex or masturbation, but each recording has only one main vocalizer (1950 female, 289 male). Both acoustic features and arousal ratings from an online perceptual experiment with 109 listeners recruited on Prolific follow an inverted-U curve, revealing the likely time of orgasm. Sexual vocalizations become longer, louder, more high-pitched, voiced, and unpredictable at orgasm in both men and women. Men are not less vocal overall in this sample, but women start moaning at an earlier stage; speech or even minimally verbalized exclamations are uncommon. While excessive vocalizing sounds inauthentic to listeners, vocal bursts at peak arousal are ubiquitous and less verbalized than in the build-up phase, suggesting limited volitional control. Human sexual vocalizations likely include both consciously controlled and spontaneous moans of pleasure, which are perhaps best understood as sounds of liking rather than signals specific to copulation.
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| 3. |
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| 4. |
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| 5. |
- Bolund, Elisabeth
(författare)
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The challenge of measuring trade-offs in human life history research
- 2020
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Ingår i: Evolution and human behavior. - : Elsevier BV. - 1090-5138 .- 1879-0607. ; 41:6, s. 502-512
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Tidskriftsartikel (refereegranskat)abstract
- Life history theory has become a prominent framework in the evolutionary social sciences, and the concept of trade-offs, the cornerstone of life history theory in studies on non-human taxa, has likewise been widely adopted. Yet, human life history research often assumes trade-offs without demonstrating them. This is not surprising given the practical difficulties in measuring trade-offs in long-lived animals, like humans. Four main methods are used to demonstrate trade-offs: phenotypic correlations, experimental manipulations, genetic correlations and correlated responses to selection. Here, I discuss challenges with these methods along with potential solutions. For example, individual heterogeneity within a population in quality or access to resources can mask underling trade-offs, and this can be accounted for by careful experimental manipulation or proper statistical treatment of observational data. In general, trade-offs have proven more difficult than expected to measure, and evidence across species is mixed, but strong evidence exists in some cases. I use the key trade-off between reproduction and survival to exemplify methods, challenges and solutions, and review the mixed evidence for a cost of reproduction in humans. I conclude by providing directions for future research. Promising avenues are opening thanks to recent advances in quantitative genetic and genomic methods coupled with the availability of high-quality large-scale datasets on humans from different populations, allowing the study of the evolutionary implications of life history trade-offs in humans.
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| 6. |
- Campbell, Benjamin, et al.
(författare)
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The 7R polymorphism in the dopamine receptor D(4) gene (DRD4) is associated with financial risk taking in men
- 2009
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Ingår i: Evolution and Human Behavior. - : Elsevier. - 1090-5138. ; 30:2, s. 85-92
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Tidskriftsartikel (refereegranskat)abstract
- Individuals exhibit substantial heterogeneity in financial risk aversion. Recent work on twins demonstrated that some variation is influenced by individual heritable differences. Despite this, there has been no study investigating possible genetic loci associated with financial risk taking in healthy individuals. Here, we examined whether there is an association between financial risk preferences, elicited experimentally in a game with real monetary payoffs, and the presence of the 7-repeat allele (7R+) in the dopamine receptor D(4) gene as well as the presence of the Al allele (Al+) in the dopamine receptor D(2) gene in 94 young men. Although we found no association between the Al allele and risk preferences, we did find that 7R+ men are significantly more risk loving than 7R- men. This polymorphism accounts for roughly 20% of the heritable variation in financial risk taking. We suggest that selection for the 7R allele may be for a behavioral phenotype associated with risk taking. This is consistent with previous evolutionary explanations suggesting that selection for this allele was for behaviors associated with migration and male competition, both of which entail an element of risk. (C) 2009 Elsevier Inc. All rights reserved.
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| 7. |
- Conroy-Beam, Daniel, et al.
(författare)
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Assortative mating and the evolution of desirability covariation
- 2019
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Ingår i: Evolution and human behavior. - : Elsevier. - 1090-5138 .- 1879-0607. ; 40:5, s. 479-491
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Tidskriftsartikel (refereegranskat)abstract
- Mate choice lies dose to differential reproduction, the engine of evolution. Patterns of mate choice consequently have power to direct the course of evolution. Here we provide evidence suggesting one pattern of human mate choice-the tendency for mates to be similar in overall desirability-caused the evolution of a structure of correlations that we call the d factor. We use agent-based models to demonstrate that assortative mating causes the evolution of a positive manifold of desirability, d, such that an individual who is desirable as a mate along any one dimension tends to be desirable across all other dimensions. Further, we use a large cross-cultural sample with n = 14,478 from 45 countries around the world to show that this d-factor emerges in human samples, is a cross-cultural universal, and is patterned in a way consistent with an evolutionary history of assortative mating. Our results suggest that assortative mating can explain the evolution of a broad structure of human trait covariation.
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| 8. |
- Cownden, Daniel, et al.
(författare)
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A popular misapplication of evolutionary modeling to the study of human cooperation
- 2017
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Ingår i: Evolution and human behavior. - : Elsevier BV. - 1090-5138 .- 1879-0607. ; 38:3, s. 421-427
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Tidskriftsartikel (refereegranskat)abstract
- To examine the evolutionary basis of a behavior, an established approach (known as the phenotypic gambit) is to assume that the behavior is controlled by a single allele, the fitness effects of which are derived from a consideration of how the behavior interacts, via life-history, with other ecological factors. Here we contrast successful applications of this approach with several examples of an influential and superficially similar line of research on the evolutionary basis of human cooperation. A key difference is identified: in the latter line of research the focal behavior, cooperation, is abstractly defined in terms of immediate fitness costs and benefits. Selection is then assumed to act on strategies in an iterated social context for which fitness effects can be derived by aggregation of the abstractly defined immediate fitness effects over a lifetime. This approach creates a closed theoretical loop, rendering models incapable of making predictions or providing insight into the origin of human cooperation. We conclude with a discussion of how evolutionary approaches might be appropriately used in the study of human social behavior.
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| 9. |
- de Barra, Mícheál, et al.
(författare)
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Illness in childhood predicts face preferences in adulthood
- 2013
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Ingår i: Evolution and human behavior. - : Elsevier BV. - 1090-5138 .- 1879-0607. ; 34:6, s. 384-389
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Tidskriftsartikel (refereegranskat)abstract
- The value of different mate choices may depend on the local pathogen ecology and on personal infection susceptibility: when there is a high risk of infection, choosing a healthy or immunocompetent mate may be particularly important. Frequency of childhood illness may act as a cue of the ecological and immunological factors relevant to mate preferences. Consistent with this proposal, we found that childhood illness - and frequency of diarrhea in particular - was positively correlated with preferences for exaggerated sex-typical characteristics in opposite-sex, but not same-sex, faces. Moreover, this relationship was stronger among individuals with poorer current health. These data suggest that childhood illness may play a role in calibrating adult mate preferences and have implications for theories of disease-avoidance psychology, life-history strategy and cross-cultural differences in mate preferences.
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| 10. |
- Ellingsen, Tore, et al.
(författare)
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Anticipated verbal feedback induces altruistic behavior
- 2008
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Ingår i: Evolution and Human Behavior. - : Elsevier. - 1090-5138. ; 29:2, s. 100-105
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Tidskriftsartikel (refereegranskat)abstract
- A distinctive feature of humans compared to other species is the high rate of cooperation with nonkin. One explanation is that humans are motivated by concerns for praise and blame. In this paper we experimentally investigate the impact of anticipated verbal feedback on altruistic behavior. We study pairwise interactions in which one subject, the “divider,” decides how to split a sum of money between herself and a recipient. Thereafter, the recipient can send an unrestricted anonymous message to the divider. The subjects' relationship is anonymous and one-shot to rule out any repeated interaction effects. Compared to a control treatment without feedback messages, donations increase substantially when recipients can communicate. With verbal feedback, the fraction of zero donations decreases from about 40% to about 20%, and there is a corresponding increase in the fraction of equal splits from about 30% to about 50%. Recipients who receive no money almost always express disapproval of the divider, sometimes strongly and in foul language. Following an equal split, almost all recipients praise the divider. The results suggest that anticipated verbal rewards and punishments play a role in promoting altruistic behavior among humans.
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