Gillian Brown

Human beings persist in an extraordinary range of ecological settings, in the process exhibiting enormous behavioural diversity, both within and between populations. People vary in their social, mating and parental behaviour and have diverse and elaborate beliefs, traditions, norms and institutions. The aim of this theme issue is to ask whether, and how, evolutionary theory can help us to understand this diversity. In this introductory article, we provide a background to the debate surrounding how best to understand behavioural diversity using evolutionary models of human behaviour. In particular, we examine how diversity has been viewed by the main subdisciplines within the human evolutionary behavioural sciences, focusing in particular on the human behavioural ecology, evolutionary psychology and cultural evolution approaches. In addition to differences in focus and methodology, these subdisciplines have traditionally varied in the emphasis placed on human universals, ecological factors and socially learned behaviour, and on how they have addressed the issue of genetic variation. We reaffirm that evolutionary theory provides an essential framework for understanding behavioural diversity within and between human populations, but argue that greater integration between the subfields is critical to developing a satisfactory understanding of diversity.

Height preferences when choosing a partner might reflect adaptive mating strategies, whereby tall men are deemed attractive to potential partners due to links with health and resource acquisition. However, height preferences are highly variable across populations and could reflect socially constructed gender norms. We examined the relationship between ideal partner height, the importance placed on partner height and endorsement of traditional gender norms. Participants (n = 242; 18-39yrs; UK-based, heterosexual) completed (i) five height-related questions (including own height, ideal partner height, maximum/minimum acceptable height), (ii) three gender norm questionnaires (sexist attitudes, feminist attitudes and alignment with masculine/feminine gender roles), and (iii) two open-ended questions about why height is important. Although ideal height ratio did not correlate with any gender role endorsement measures in either women or men, women who placed greater importance on height scored higher on sexism, lower on feminism and were less likely to find a short partner acceptable than women who placed less importance on partner height. Men who placed greater importance on height, and men who described themselves as more traditionally masculine, were less willing to accept a tall partner than men who scored lower on these measures. Women who rated height as important wanted to feel ‘feminine/protected’, whereas men wanted to feel ‘masculine/dominant’. In this study, the ‘male-taller’ preference was exhibited, with women’s preferences for tall partners being stronger than men’s preferences for short partners. Height preferences were related to gender norm endorsement, suggesting that gene–culture co-evolutionary processes could potentially influence human height dimorphism.

Human beings persist in an extraordinary range of ecological settings, in the process exhibiting enormous behavioural diversity, both within and between populations. People vary in their social, mating and parental behaviour and have diverse and elaborate beliefs, traditions, norms and institutions. The aim of this theme issue is to ask whether, and how, evolutionary theory can help us to understand this diversity. In this introductory article, we provide a background to the debate surrounding how best to understand behavioural diversity using evolutionary models of human behaviour. In particular, we examine how diversity has been viewed by the main subdisciplines within the human evolutionary behavioural sciences, focusing in particular on the human behavioural ecology, evolutionary psychology and cultural evolution approaches. In addition to differences in focus and methodology, these subdisciplines have traditionally varied in the emphasis placed on human universals, ecological factors and socially learned behaviour, and on how they have addressed the issue of genetic variation. We reaffirm that evolutionary theory provides an essential framework for understanding behavioural diversity within and between human populations, but argue that greater integration between the subfields is critical to developing a satisfactory understanding of diversity.

What is the job that the term ‘human nature’ is expected to do? Three notions are prevalent but are problematic: (1) Distinguishing what is biological from what is cultural/environmental. Here the term fails. (2) Characterizing the defining features of humanity, thereby allowing us to be distinguished from other species. This stance is tenable but contributes little. (3) Characterizing what is universal or typical about humanity, because of our ‘evolved biological heritage’. Here the term is tenable but misleading and hence counterproductive. ‘Human nature’ is equally reciprocally caused by gene–culture coevolution and niche construction. Given that the term has little explanatory power but carries extensive baggage, we suggest that it should be abandoned. It can be replaced with descriptions of human behaviour and cognition as the product of socially mediated internal and external constructive processes operating over both developmental and evolutionary timescales.

Wood, Kressel, Joshi, and Louie (2014) thoroughly evaluate the evidence for menstrual cycle shifts in ratings of several male characteristics and conclude that their analyses fail to provide supportive evidence for consistent cycle effects. The topic of menstrual cycle shifts in mate preferences has been strongly debated, with disagreements over both scientific content and practice. Here, we attempt to take a step back from these acrimonious exchanges and focus instead on how to interpret menstrual cycle shifts in mate preference tasks, independently from the question of when, or if, task performance varies with cycle stage. A greater consideration of domain-general mechanisms could provide an opportunity for investigating how evolved predispositions interact with socially transmitted information in biasing women’s responses on mate preference tasks.