Adaptive Human Behavior and Physiology最新文献

This study experimentally tested the impact of perceived physical resemblance on ascriptions of close relationships between individuals. Following kin selection theory, if physical resemblance is a proxy for genetic relatedness, it is adaptive to act altruistically toward similar-looking individuals who may share genes in common, yet select dissimilar-appearing romantic partners to avoid mating that may result in inbreeding depression or lack of offspring diversity.

Participants were shown sets of paired facial photos of two persons varying in physical resemblance to one another, who were labeled as being either friends, siblings, or romantic partners. Raters evaluated the closeness of each pair’s relationship based on their pictures. Another set of raters was shown the same pairs of photos without relationship labels and was asked to evaluate how likely they thought the pairs were siblings, friends, or romantic partners, respectively.

Across all conditions, pairs exhibiting greater perceived physical resemblance were rated as having closer/higher-quality relationships and were more likely thought to be siblings or friends, but were less likely seen as romantic partners. Similar patterns were found when participants (n = 526) were asked about their own personal relationships; generally, ratings of both perceived physical and behavioral similarity were positively associated with perceived relationship closeness across all relationship types, even when controlling for factors such as relationship length and residence distance.

In line with kin selection theory, participants ascribed closer relationships to those who appeared more genetically related but were less likely to identify similar-looking pairs as being romantic partners.

Purpose

Aggressive behavior is influenced by genetic factors, but findings in behavioral genetics remain inconsistent due to heterogeneous study samples. This study aims to investigate the relationship between aggression traits and polymorphisms of AR, HTR2A, and OXTR genes in a monoethnic sample of Armenian university students, and to compare the results with previously studied African and Siberian populations.

Methods

The study included 231 Armenian students. Aggression levels were assessed using the Buss-Perry Aggression Questionnaire and proactive/reactive aggression scales. Genetic analysis focused on the OXTR-rs53576, HTR2A-rs6311, and AR(CAG)_n polymorphisms. The distribution of alleles was examined, and associations between genetic variations and aggression traits were analyzed, considering sex differences and gene–gene interactions.

Results

Men exhibited significantly higher levels of physical (p = 2.8e-8), proactive (p = 2.8e-8), and reactive aggression (p = 0.015), while hostility was more pronounced in women (p = 0.033). In women, OXTR-rs53576 interacted with AR(CAG)_n to influence reactive aggression (p = 0.015). In men, AR(CAG)_n independently affected physical aggression (p = 0.003), and its interaction with OXTR-rs53576 also influenced physical aggression (p = 0.005). Combined analysis revealed that AR(CAG)_n and OXTR-rs53576 interactions were associated with verbal aggression (p = 0.008), anger (p = 0.035), and reactive aggression (p = 0.029).

Conclusion

Our findings suggest that genetic variations in AR and OXTR contribute to individual differences in aggression, with sex-specific effects and gene–gene interactions playing a significant role. In a comparative context, Armenians demonstrate intermediate levels of aggression between highly egalitarian and patriarchal societies, reinforcing the importance of both genetic and sociocultural factors in the expression of aggression.

Purpose

People can judge others’ ages from face images somewhat accurately and tend to rateyounger adults’ faces as more attractive than older adults’ faces. However, individual diff erences inthe strength of this preference for younger adult faces have also been reported, whereby peopleborn to older parents (i.e., people whose parents were older when the participant was born) showedweaker preferences for younger adult faces. However, work showing this pattern of results used facestimuli in which cues of age were experimentally manipulated using computer-graphics methods andmany researchers have recently raised concerns about how well fi ndings obtained using such stimuligeneralise to ratings of natural (i.e., unmanipulated) face images.

Methods

In light of the above, we tested whether people born to older parents showed weakerpreferences for younger faces when rating the attractiveness of natural (i.e., unmanipulated) faceimages.

Results

Although our analyses demonstrated that participants generally showed strong preferencesfor younger adult faces, the strength of these preferences was not signifi cantly correlated withparental age at birth.

Conclusions

Thus, our results do not support the proposal that parental age at birth infl uencespreferences for facial cues of age.

Objectives

This study examines the complex dynamics of father-daughter relationships, focusing on how life history factors are associated with paternal behaviors towards daughters. Drawing on Life history Theory and the Daughter-Guarding hypothesis, the research investigates how these factors contribute to father-daughter interactions, such as attachment, protection, support, and control received from fathers.

Methods

Two surveys were conducted: one with 120 daughters aged 18–21 (Study 1) and another with 120 fathers (Study 2), both recruited through online platforms. Study 1 examined the relationship from the daughters’ perspective, while Study 2 explored it from the fathers’ perspective.

Results

Fathers with higher education and stable financial backgrounds showed stronger attachment, support, and protection to their daughters. Additionally, daughters’ self-perceived attractiveness was associated with paternal behaviors, suggesting that attractive daughters were more likely to receive support, protection, and develop stronger attachments to their fathers.

Conclusions

The findings emphasize the need for further research into the relationships of these factors, particularly across diverse cultural and socioeconomic backgrounds, to better understand their role in shaping father-daughter relationships and the potential effects on female development.

Purpose

Competence and prosociality of the person being helped are important indicators for ensuring a return on help, as reciprocity would not be possible if the person being helped lacked either the competence or the inclination to reciprocate in the future. A previous study that measured compassion using a Likert scale found that the controllability of the cause of the difficulty and the level of the sufferer’s prosociality independently influenced the degree of compassion. In this study, we aimed to examine how the probability of reciprocity affects physiological responses (such as heart rate), as well as psychological responses, to the suffering of others.

Methods

Participants’ heart rates were monitored while they watched a video of a man monologuing about his difficulty. Compassion was also measured using a Likert scale. In Study 1, we investigated the effect of the controllability of the difficulty on heart rate. In Study 2, we provided participants with additional information about the prosociality of the man in the video.

Results

Controllability affected compassion ratings, replicating the results of previous studies. Although participants’ heart rates decreased when they learned that the man was suffering, the controllability of the cause did not influence the degree of decline.

Conclusion

The results suggest that people experience compassion at a physiological level, while the controllability of the difficulty (i.e., a cue for reciprocity) is processed subjectively and reflected only in consciously reported psychological measures, which may reflect the evolutionary history of compassion.

Purpose

Infectious diseases have posed an existential threat to humans throughout history, resulting in a complex system of evolved psychological and behavioral mechanisms designed to help mitigate infection. Given that food consumption represents a significant route through which humans can be exposed to illness-causing pathogens, further research into the relationship between disease avoidance motivations and novel food avoidance (i.e., food neophobia) is warranted.

Methods

Across three studies (total N = 736), we investigated the relationship between trait disease avoidance motivation (assessed by the Perceived Vulnerability to Disease scale) and food neophobia.

Results and Conclusions

Results from each of the three studies indicated that greater dispositional germ aversion significantly predicted greater food neophobia, whereas the relationship between dispositional perceived infectability and food neophobia was positive but more variable across the studies. Additionally, Study 3 revealed that while greater dispositional food neophobia predicted greater likelihood of avoiding foreign foods, experimentally priming disease threat was not associated with food choice. Lastly, an internal meta-analysis revealed that both germ aversion and perceived infectability were both uniquely positively associated with food neophobia. Limitations, conceptual issues, and avenues for future research are discussed.

Purpose

Research using system integrity theory (SIT) has shown that more intelligent men have higher-quality semen, which is puzzling because although reproductive capability should predict fertility, more intelligent men have fewer children. The current research addresses this puzzle by highlighting the distinct obligate and facultative outcomes that emerge when SIT is integrated with life history theory (LHT) and evolutionary novelty theory (ENT). Specifically, we propose that SIT accounts for more rigidly obligate physiological traits whereas LHT encompasses both obligate traits and flexibly facultative behaviors and, thus, permits the ENT-driven expectation that brighter individuals would act in evolutionarily novel ways—e.g., slower reproduction despite possessing capacities for faster reproduction.

Methods

We examined this logic using another obligate reproductive trait: the timing of puberty. Based on our proposed synthesis of SIT, LHT, and ENT, we tested the prediction that more intelligent people would experience puberty earlier and yet have sex later, engage in less sexual activity, and have fewer children using two nationally representative and generationally distinct samples from the NCDS and Add Health.

Results

Data across both samples confirmed that higher intelligence predicted earlier puberty and indicators of slower reproduction over and above several potential confounds, thus constituting a robust validation of our propositions.

Conclusions

Findings are discussed with regards to the importance of considering the interplay between obligate and facultative traits, particularly when opposing directions might occur due to evolutionarily novel preferences associated with intelligence, as well as in the context of evolutionary mismatch in modern settings. Future directions inspired by this novel synthesis are offered.

Purpose

Uric acid (UA), the end product of purine metabolism, serves as a potent deoxidant of the brain. UA may therefore be related to psychological activities that are culturally endorsed and normatively promoted, insofar as such activities would require high levels of cortical processing, and thus, gradually expose the brain to a greater oxidation risk. We tested this analysis in Japan, a society that values interdependence of the self with others.

Methods

Middle-aged Japanese adults (N = 243) were tested twice for the serum UA concentration, with five years in-between. Moreover, an assortment of measures assessing culturally sanctioned traits (those related to interdependence) and culturally non-sanctioned traits (those related to independence) were collected.

Results

We found that the baseline levels of interdependence predicted an increase in the UA in the next five years. In contrast, there was no such effect for independence. Moreover, the effect of interdependence on the UA increase was mediated by cognitive effort in various domains (such as work, finance, and social relations), suggesting that the culturally sanctioned traits increased cognitive effort devoted to mundane everyday activities, which in turn, predicted the UA to increase over time. Notably, baseline UA levels did not affect changes in psychological traits.

Conclusion

Interpreting these results in light of UA’s role as a potent antioxidant for brain tissues, we propose that higher UA levels may support metabolically demanding actions aligned with culturally sanctioned practices, particularly those associated with interdependence in the Japanese context.

Objectives

Social feedback plays a pivotal role in human interactions, significantly impacting psychological and behavioral processes. This study explored the effect of different types of social feedback on neurophysiological function in the context of psychosocial stress and performance.

Methods

Thirty-nine healthy adults underwent a modified version of the Trier Social Stress Test, in which they prepared and gave five short speeches, each associated with a different social feedback condition: No Feedback, (NoF), Neutral Feedback (NF), Annoyed Feedback (AF), Bored Feedback (BF), and Positive Feedback (PF). Data on electroencephalography (EEG), heart rate (HR), and electrodermal activity (SCL) were collected during the speech preparation phase and following social feedback.

Results

HR and SCL were significantly lower in the AF and BF conditions compared to the NoF and NF conditions. Furthermore, EEG data showed higher gamma band activity in the posterior region of interest compared to frontal and central areas; this activity increased from the NoF to the PF, NF, and BF conditions, peaking before declining in the AF condition. Beta band activity was higher in central and posterior regions than in the frontal area and increased from NoF to NF before decreasing in the BF and AF conditions.

Conclusions

These results illustrate how social feedback may or may not induce psychosocial stress depending on its valence and identify some potential neurophysiological correlates of adaptive and maladaptive performance under stress.

Purpose

The present study aimed to investigate the extent to which violent intergroup conflict may be associated with human life history trajectories.

Methods

We examined life histories in a postconflict socioecology (Bosnia and Herzegovina and Kosovo: N = 699) and compared them with a control condition (Serbia: N = 628) using the network analysis approach.

Results

Participants from the postconflict environment had higher number of children and reproduction planning, followed by lower age of first reproduction which suggest accelerated life histories. Network analysis showed that fertility and mating-related events in the control ecology were relatively independent from childhood environmental conditions, while fertility itself was positively associated with current socioeconomic status. In contrast, fertility and mating were linked with childhood economic family status and stability of the environment in the postconflict condition; current socioeconomic status was only related to childhood economic status in this network. Short-term mating and the onset of sexual behavior were more strongly positively related to the age of first reproduction in the postconflict socioecology, compared to the control socioecology. Fertility was positively associated with long-term mating and pregnancy planning, and negatively linked with the age of first reproduction in both ecological conditions.

Conclusions

Obtained findings are discussed within the theoretical frameworks of fast-slow continuum in life history trajectories and predictive adaptive response hypothesis. The results provide insights into how intergroup conflict may affect human life history dynamics and highlights the fruitfulness of using the network approach to analyze life history trajectories.