For the union
The relative importance of intra- and intersexual selection on human male sexually dimorphic traits
Tobias Kordsmeyer et al.
Evolution and Human Behavior, forthcoming
Abstract:
Recent evidence suggests that in sexual selection on human males, intrasexual competition plays a larger role than female choice. In a sample of men (N = 164), we sought to provide further evidence on the effects of men's physical dominance and sexual attractiveness on mating success and hence in sexual selection. Objective measures and subjective ratings of male sexually dimorphic traits purportedly under sexual selection (height, vocal and facial masculinity, upper body size from 3D scans, physical strength, and baseline testosterone) and observer perceptions of physical dominance and sexual attractiveness based on self-presentation video recordings were assessed and associated with mating success (sociosexual behaviour and number of potential conceptions) in a partly longitudinal design. Results from structural equation models and selection analyses revealed that physical dominance, but not sexual attractiveness, predicted mating success. Physical dominance mediated associations of upper body size, physical strength, as well as vocal and facial physical dominance and attractiveness with mating success. These findings thus suggest a greater importance of intrasexual competition than female choice in human male sexual selection.
The relationship implications of rejecting a partner for sex kindly versus having sex reluctantly
James Kim, Amy Muise & Emily Impett
Journal of Social and Personal Relationships, May 2018, Pages 485-508
Abstract:
Romantic partners often have differing levels of sexual interest. In these situations, lower desire partners may engage in sex for avoidance goals (e.g., to avoid disappointing their partner), which are associated with negative relational outcomes. An alternative strategy to sustain relationship quality may be to decline a partner’s sexual advances in positive ways. In two experimental studies and a dyadic daily experience study with a longitudinal follow-up, we examined the relationship outcomes of positive rejection compared to avoidance-motivated sex. Across studies, when people engaged in positive rejection, both they and their partner did not experience lower levels of relationship satisfaction compared to when they had sex for avoidance goals, although this was not true for sexual satisfaction. Chronic pursuit of sex for avoidance goals did, however, have detrimental consequences over time, whereas positive rejection helped sustain relationship satisfaction. Results suggest positive rejection behaviors may be a viable alternative to avoidance-motivated sex.
Fertile women evaluate male bodies as more attractive, regardless of masculinity
Julia Jünger et al.
Evolution and Human Behavior, forthcoming
Abstract:
Ovulatory cycle shifts in women's mate preferences have been documented for several physical and behavioral traits. Research suggests that, at peak fertility, women tend to prefer men with characteristics that reflect good genes for short-term sexual relationships. However, existing findings have been criticized for methodological flexibility and failing attempts to replicate core results. In a large (N = 157), pre-registered, within-subject study spanning two ovulatory cycles, we investigated cycle shifts in women's mate preferences for masculine bodies. Using a large set of natural stimuli, we found that when fertile, women's ratings of male bodies increased for sexual as well as for long-term attractiveness. Both effects were partially mediated by the estradiol-to-progesterone-ratio. Furthermore, moderation analyses revealed that both shifts were only evident in women in relationships, but not in singles. Contrary to previous findings, male masculine traits did not interact with cycle phase to predict attraction, indicating that women's preferential priorities do not shift. Taken together, our results do not support women's mate preference shifts, as assumed by the good genes ovulatory shift hypothesis, but are consistent with shifting motivational priorities throughout the cycle. Implications of these results for female estrus theories and methodological recommendations for future research are discussed.
Who is sexually faithful? Own and partner personality traits as predictors of infidelity
Emma Altgelt et al.
Journal of Social and Personal Relationships, May 2018, Pages 600-614
Abstract:
Infidelity can have harmful consequences for all those involved. Although prior research has demonstrated some reliable associations between certain personality traits and infidelity, the associations between other personality traits and infidelity are less clear. Moreover, prior research has been limited in addressing the role of partner personality and whether any effects are independent of relationship satisfaction. Thus, we pooled data from two 3-year longitudinal studies of newlywed couples to examine the associations between both couple members’ personality (Big Five and narcissism) and infidelity, controlling and not controlling for marital satisfaction. Wives high (versus low) in extraversion and husbands and wives with partners high (versus low) in neuroticism or extraversion were more likely to engage in infidelity regardless of whether we controlled for satisfaction. Husbands with partners high (versus low) in narcissism were more likely to engage in infidelity, though this effect was no longer significant when controlling for satisfaction. These findings demonstrate that even predicting a behavior as self-oriented as infidelity requires considering the qualities of both couple members, highlighting the importance of adopting a dyadic approach to relationships.
A high-powered replication study finds no effect of starting or stopping hormonal contraceptive use on relationship quality
Patrick Jern et al.
Evolution and Human Behavior, forthcoming
Abstract:
A number of recent studies have implicated that incongruent use of hormonal contraceptives (HCs) negatively affects various aspects of women's romantic relationships. It has been suggested that women with incongruent HC use (a discrepancy in HC use status between when they first met their current partner and the time of study participation) report less sexual satisfaction and higher jealousy scores compared to women with congruent HC use. A similar effect has also been hypothesized for general relationship satisfaction, and recent findings suggest that the association between HC incongruency and general relationship satisfaction is moderated by women's perceived facial attractiveness of male partners. Using a large convenience sample (N = 948) of Finnish women, we attempted to replicate previously reported findings but found no support for the HC congruency hypothesis, despite excellent statistical power (≥98.7%) to detect previously reported effect sizes. Instead, after dividing our sample into four groups based on HC congruency/incongruency, we found that the largest differences in jealousy, sexual satisfaction, and relationship satisfaction scores tended to be found between women who were consistent HC users and consistent non-users (i.e., between women with different kinds of congruent HC use). We also detected a significant main effect of current HC use on jealousy. We conclude that, as the effect size of the HC incongruency effect reported in previous studies was small, unequal distributions of current HC users within congruent and incongruent HC user groups may give rise to spurious HC incongruency effects in studies using small samples.
To “See” Is to Feel Grateful? A Quasi-Signal Detection Analysis of Romantic Partners’ Sacrifices
Mariko Visserman et al.
Social Psychological and Personality Science, forthcoming
Abstract:
Although gratitude plays a central role in the quality of relationships, little is known about how gratitude emerges, such as in response to partners’ sacrifices. Do people need to accurately see these acts to feel grateful? In two daily experience studies of romantic couples (total N = 426), we used a quasi-signal detection paradigm to examine the prevalence and consequences of (in)accurately “seeing” and missing partners’ sacrifices. Findings consistently showed that sacrifices are equally likely to be missed as they are to be accurately detected, and about half of the time people “see” a sacrifice when the partner declares none. Importantly, “seeing” partners’ sacrifices — accurately or inaccurately — is crucial for boosting gratitude. In contrast, missed sacrifices fail to elicit gratitude, and the lack of appreciation negatively colors the partner’s satisfaction with the relationship when having sacrificed. Thus, these findings illustrate the power that perception holds in romantic couples’ daily lives.
More than skin deep: Major histocompatibility complex (MHC)-based attraction among Asian American speed-daters
Karen Wu et al.
Evolution and Human Behavior, forthcoming
Abstract:
What might explain our instinctual attraction to certain individuals, aside from visible factors such as appearance? We examined possible biologically-driven selection for immunology genes, specifically preferences for Major Histocompatibility Complex (MHC)-dissimilarity, through the ecologically-valid method of speed-dating. Two-hundred-and-sixty-two single Asian Americans went on speed-dates (N observations = 2215) with participants of the other sex, making second date offers and rating each other on measures of mate desirability, facial attractiveness, and body scent attractiveness. Using a single nucleotide polymorphism (SNP) analysis, women, but not men, showed preferences for speed-dating partners based on MHC-complementarity. The direction of findings varied by single nucleotide polymorphism (SNP), such that SNPs closer to the major HLA (Human Leukocyte Antigen) genes supported dissimilarity preferences, whereas those farther away supported similarity preferences. The relative effects of MHC-based measures in comparison to an array of behavioral predictors were examined via random forests. Results indicated that for both men and women, the importance of MHC-based indices was comparable to that of a partner's self-reported personality attributes in predicting second date offers.