Getting it on

Kevin Lewis

December 02, 2017

Expected, ideal, and actual relational outcomes of emerging adults' "hook ups"
Eliza Weitbrecht & Sarah Whitton
Personal Relationships, forthcoming


Despite the prevalence of "hooking up" among emerging adults, little is known about the outcomes of these encounters. A sample of 348 college students completed a survey on expected, ideal, and actual relational outcomes of hook ups (assessed at a 10-week follow-up). Results showed that most men and women expected outcomes involving minimal commitment (i.e., nothing more, continued sexual involvement). Ideal outcomes of hook ups differed by gender, with women more often hoping for romantic involvement, and men more likely to view continued sexual involvement as ideal. Actual outcomes varied, with continued sexual involvement the most common outcome (32.2%), followed by friendship (27.7%), romantic involvement (23.2%), and nothing more (17%); 43.8% of participants experienced fulfillment of ideal outcomes.

Mating strategy flexibility in the laboratory: Preferences for long- and short-term mating change in response to evolutionarily relevant variables
Andrew Thomas & Steve Stewart-Williams
Evolution and Human Behavior, forthcoming


One of the great challenges for evolutionary psychology has been to explain within-sex individual variation in mating behaviour. Several lines of evidence suggest that some of this variation stems from an adaptation for facultatively increasing or decreasing long- and short-term mating inclinations in response to circumstances. It remains unclear, however, how rapidly such changes can occur, and what stimuli might initiate them. This paper presents three experiments that investigate mating strategy change following exposure to the evolutionarily-relevant stimuli of parental care, resource-abundance, and danger. In each experiment, participants indicated their preferred relationship type (long-term, short-term, or none) for each of fifty other-sex individuals, both before and after priming. Relative to a control group, relationship preferences changed in all three experiments, in directions generally consistent with evolutionary psychological predictions. Moreover, short- and long-term relationship preferences were found to shift independently, such that a change in long-term preference was not accompanied by an opposite change in short-term, or vice versa. Together, these experiments represent the first direct test of the claim that brief interventions can shift the relative strength of people's preferences for long-term and short-term relationships.

Arching the Back (Lumbar Curvature) as a Female Sexual Proceptivity Signal: An Eye-Tracking Study
Farid Pazhoohi et al.
Evolutionary Psychological Science, forthcoming


It is common in studies of human mate preference to have participants judge the attractiveness of photographs in which models adopt a neutral facial expression or a neutral body posture. However, it is unlikely that humans adopt neutral expressions and postures in normal social circumstances. One way in which posture can vary is in the curvature of the lower spine. In some non-human animals, a "lordotic" posture (in which the lower spine is curved towards the belly) is associated in females with readiness to mate. In humans, this posture may serve a similar function, attracting heterosexual men. In this study, participants were presented with computer-generated images of female bodies in which the back curvature was systematically manipulated. The result showed that small changes in lumbar curvature are associated with changes in the perception of attractiveness. Specifically, the result showed that there is a relationship between the range of the back curvatures used in this study and attractiveness, such that increasing the curvature increased the perception of attractiveness. Additionally, as the curvature increased, participants looked longer and fixated more on the hip region of the female bodies. This paper argues that the attractiveness of women in lordotic posture is due to a conserved mechanism across the taxa which signals proceptivity to men.

Why Women Wear High Heels: Evolution, Lumbar Curvature, and Attractiveness
David Lewis et al.
Frontiers in Psychology, November 2017


Despite the widespread use of high-heeled footwear in both developing and modernized societies, we lack an understanding of this behavioral phenomenon at both proximate and distal levels of explanation. The current manuscript advances and tests a novel, evolutionarily anchored hypothesis for why women wear high heels, and provides convergent support for this hypothesis across multiple methods. Using a recently discovered evolved mate preference, we hypothesized that high heels influence women's attractiveness via effects on their lumbar curvature. Independent studies that employed distinct methods, eliminated multiple confounds, and ruled out alternative explanations showed that when women wear high heels, their lumbar curvature increased and they were perceived as more attractive. Closer analysis revealed an even more precise pattern aligning with human evolved psychology: high-heeled footwear increased women's attractiveness only when wearing heels altered their lumbar curvature to be closer to an evolutionarily optimal angle. These findings illustrate how human evolved psychology can contribute to and intersect with aspects of cultural evolution, highlighting that the two are not independent or autonomous processes but rather are deeply intertwined.

Stability and Change in In-Group Mate Preferences among Young People in Ethiopia Are Predicted by Food Security and Gender Attitudes, but Not by Expected Pathogen Exposures
Craig Hadley & Daniel Hruschka
Human Nature, December 2017, Pages 395-406


There is broad anthropological interest in understanding how people define "insiders" and "outsiders" and how this shapes their attitudes and behaviors toward others. As such, a suite of hypotheses has been proposed to account for the varying degrees of in-group preference between individuals and societies. We test three hypotheses related to material insecurity, pathogen stress, and views of gender equality among cross-sectional (n = 1896) and longitudinal (n = 1002) samples of young people in Ethiopia (aged 13-17 years at baseline) to explore stability and change in their preferences for coethnic spouses. We show that food insecurity is associated with a greater likelihood of intolerant mate preferences. We also find that young people who hold more gender equitable attitudes tended to hold more tolerant mate preferences. Finally, we find no support for the hypothesis that expected pathogen exposure is associated with intolerant mate preferences. Our results most strongly support a material insecurity hypothesis of in-group bias, which assumes that uncertainty over meeting basic needs leads people to favor those in their in-group. As such, our findings join a small but growing group of studies that highlight the importance of material insecurity for understanding tolerance, xenophobia, in-group bias, and favoritism.

Getting to know you: Teasing as an invitation to intimacy in initial interactions
Michael Haugh & Danielle Pillet-Shore
Discourse Studies, forthcoming


It is commonly assumed that teasing is restricted to encounters among intimates or close acquaintances. As a result of examining initial interactions among (American and Australian) speakers of English, however, this article shows that teasing also occurs between persons who are becoming acquainted. Analysis reveals that tease sequences unfold across three actions that constitute the tease as an invitation to intimacy: a teasable action on the part of the target, the tease proper and a moment of interactionally generated affiliation. Given teasing is one way of criticising another, it constitutes a potential breach of tact or interactional propriety. In initial interactions, however, participants can construe this potential impropriety as an invitation to intimacy, as it involves the proposal of a shared ironic stance that may be either accepted or declined by the target of the tease.

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