Adaptive Human Behavior and Physiology最新文献

Biological differences between men and women mandate that women’s obligatory investment in reproduction is significantly greater than that of men. As a result, women have evolved to be the “choosier” of the two sexes and men have evolved to compete for female choice. To the degree that overconfidence is an effective tool for attracting mates and driving away competitors, greater competition among men suggests that they should express more overconfidence than women. Thus, sexual selection may be the primary reason why overconfidence is typically more pronounced in men than it is in women. Sexual selection may also be a distal, causal factor in what we describe as a cult of overconfidence pervading modern organizations and institutions. Whereas overconfidence was once regulated and constrained by features of ancestral life, levels of social mobility and accountability in contemporary society and modern organizations make it increasingly difficult to keep this gendered bias in check.

Objective

A growing body of research has begun investigating the relationship between hormones and female competitiveness. Many researchers have focused on the effect of the menstrual cycle and hormonal contraceptives. Despite many attempts at understanding hormone-behavior associations, contradictory findings have made it difficult to determine the existence of true effects. The aim of the current research was to use a robust methodological design to investigate the effect of fertility probability on four competitive orientations in naturally cycling women and hormonal contraceptive users.

Methods

Using a longitudinal diary study with over 3,900 observations from 21 countries, we explore the effect of fertility probability on four self-report competitive orientations after controlling for menstruation: self-developmental competition, hyper competitiveness, competition avoidance, and lack of interest toward competition.

Results

Using Bayesian estimation for ordinal mixed models, we found that fertility probability was associated with an increase in self-development competitiveness amongst naturally cycling women but not hormonal contraceptive users. We also found weak evidence that hormonal contraceptive users show reduced interest in competing compared to naturally cycling women. There were no other robust effects of fertility or hormonal contraceptive use.

Conclusions

These results suggest that fertility probability is associated with increased fluctuations in self-development competitive motivation and that hormonal contraceptives interfere with this effect. This research contributes to the growing body of literature suggesting that hormonal contraceptives may influence psychology and behavior by disrupting evolved hormonal mechanisms.

Objective

The evolutionary-contingency hypothesis, which suggests that preferences for leaders are context-dependent, has found relatively consistent support from research investigating leadership decisions based on facial pictures. Here, we test whether these results transfer to leadership decisions based on voice recordings. We examined how dominance and trustworthiness perceptions relate to leadership decisions in wartime and peacetime contexts and whether effects differ by a speaker’s gender. Further, we investigate two cues that might be related to leadership decisions, as well as dominance and trustworthiness perceptions: voice pitch and strength of regional accent.

Methods

We conducted a preregistered online study with 125 raters and recordings of 120 speakers (61 men, 59 women) from different parts in Germany. Raters were randomly distributed into four rating conditions: dominance, trustworthiness, hypothetical vote (wartime) and hypothetical vote (peacetime).

Results

We find that dominant speakers were more likely to be voted for in a wartime context while trustworthy speakers were more likely to be voted for in a peacetime context. Voice pitch functions as a main cue for dominance perceptions, while strength of regional accent functions as a main cue for trustworthiness perceptions.

Conclusions

This study adds to a stream of research that suggests that (a) people’s voices contain important information based on which we form social impressions and (b) we prefer different types of leaders across different contexts. Future research should disentangle effects of gender bias in leadership decisions and investigate underlying mechanisms that influence how people’s voices contribute to achieving social status.

Objective

Why do dominant leaders rise to power via the popular vote? This research tests whether when people feel threatened by intra-group disorder they desire stronger, more dominant leaders.

Methods

Participants (N = 1,026) read a vignette that depicts a within-group norm violation. We then used a between-subjects design to randomly assign participants to a specific version of the vignette in which (a) a focal target individual in the scenario varied in their dominance (punitiveness: from no to moderate to strong); and (b) the local group faced little or substantial intra-group conflict and disorder (threat: from low to high). Following this, participants reported how much they endorse the target individuals as leader and the individual’s perceived prestige.

Results

We find that intra-group conflict motivates a psychology that favors the rise of dominant leaders: Highly punitive individuals (seen as highly dominant) are endorsed as leaders when in-group threat is high, but comparably disfavored when threat is low. Under low threat, non-punitive individuals (who are seen as less dominant) are endorsed as leaders. Subsequent analyses reveal that these shifts in leader preferences are explained by corresponding changes in prestige. Under conditions of high threat, dominance confers prestige, whereas under low threat, dominance suppresses prestige. Tests of mediation further show that the effect of dominance on increased leader support under high threat is mediated by prestige.

Conclusions

In contexts of threat, such as internal disorder, dominant leaders are favored and gain prestige, owing to their perceived ability to supply benefits such as in mediating internal conflicts.

Abstract

Objective

Caring, sensitive parenting is known to be associated with higher levels of engagement in support-seeking behaviors among children and young adolescents. However, no study has yet explored the role of perceived parental attention in social support seeking in early adulthood. Growing evidence suggests that the µ-opioid receptor gene polymorphism (OPRM1 A118G) moderates one’s responsiveness to social environments. Prompted by the differential susceptibility theory of gene–environment interaction, the present study examined whether the OPRM1 polymorphism would moderate the association between perceived parental attention and social support seeking in early adulthood.

Methods

Six hundred and twenty Japanese undergraduate students self-reported the amount of attention they subjectively perceived their parents to have given them during childhood and completed scales that assess support-seeking behaviors. Clippings of their fingernails were collected for genotyping.

Results

The results showed that the interactive effect of perceived parental attention and OPRM1 genotypes on social support seeking was significant. Specifically, perceived parental attention only significantly and positively predicted OPRM1 GG carriers’ social support seeking in response to stress.

Conclusions

The findings support the view that OPRM1 polymorphism moderates the association between early experiences and developmental outcomes.

Objectives

A paradox exists in research on girls and women. On the one hand, they behave in a more egalitarian fashion than their male counterparts. On the other hand, status increases their own and their children’s survival.

Methods

Evidence from non-human primates can help reconcile these findings. In species that do not reside with female kin for life, females are relatively egalitarian and individualistic. They typically do not cooperate or engage in direct competition and exhibit little tolerance for status differentials.

Results and Conclusions

Women follow this pattern. While a husband’s status and her female relatives’ support enhance a woman’s status and reproductive success, her own actions too influence her access to resources and allies. Evidence on girls’ and women’s same-sex competition and quests for status supports the hypothesis that human females inhabit dispersal-egalitarian communities in which competition is avoided, an egalitarian ethos prevails, competitive behavior is disguised, and status differentials are not tolerated.

Objective

The dual-hormone hypothesis (DHH) posits that some effects of testosterone on human behavior and psychology related to status-seeking are moderated by cortisol, such that they are stronger when cortisol levels are low. In support of the DHH, studies have found that cortisol negatively moderated the relationship between testosterone and such traits as status-seeking and interest in uncommitted sex. Others indicate a positive moderating influence of cortisol in some cases. Here, we test whether two psychosexual indices—sexual desire and sociosexuality—meet the expectations of the DHH in a large sample of men and women.

Method

646 women and 185 men attended lab sessions during which they provided saliva samples for hormonal analysis and responded to the Sociosexual Orientation Inventory-Revised and the Sexual Desire Inventory (180 women and 43 men returned for a second session approximately two months later). We quantified salivary hormone concentrations using ELISA and assessed within- and between-participant effects of hormones on psychosexual measures with mixed-effects models.

Results

We observed a positive interaction between within-subjects cortisol and testosterone in models of sexual desire in both men and women. For women, these effects emerged in models of general sexual desire and in models of the dyadic desire subscale and were robust to many analytical configurations. For men, the effects were limited to models of solitary desire, but were also robust to alternative analyses. We present data to quantify our risks of both type I and type II error.

Conclusions

Some of our results contrast with usual dual-hormone hypothesis predictions of negative interactions between testosterone and cortisol. We suggest several potential explanations for these results, including a positive feedback loop whereby elevated testosterone prompts increases in sexual desire and behavior, necessitating cortisol-induced mobilization of energy stores.

Objective

Research has demonstrated that men prefer women’s voices with higher pitch and that women’s voices recorded at high compared to low fertility phases of the menstrual cycle are rated as more attractive. These findings suggest that voice conveys information relevant to reproductive success. Because voice attractiveness is higher during the high fertility phase and voice pitch positively predicts attractiveness ratings, it has been hypothesized that cyclical changes in vocal attractiveness are driven by changes in voice pitch. However, attempts to detect acoustic changes have produced mixed results. With the higher degree of ecological validity achieved by including social context (simulated interactions with men and women) and by recording voice in the three phases of menstrual cycles, the present study addresses limitations of previous research.

Methods

Forty-eight naturally cycling women were recorded during the menstrual, late follicular (high fertility), and luteal phases while leaving voice messages to masculinized and femininized men and women.

Results

No cycle-related changes in pitch and pitch variability for the recordings directed to masculinized and femininized men and women were detected. By including relationship status as predictor in additional models, higher-order interaction effects showed that single and partnered women displayed opposite cycle-related pitch changes directed only to women, but not men.

Conclusion

The cycle-related voice changes found in the present study do not support the hypothesis that cyclic pitch variations represent an adaptive mechanism for attracting partners. We discuss cyclic changes in voice pitch in relation to intrasexual competition by taking into an account that the present study is likely underpowered for adequate testing of the complex higher-order interactions.