Bateman's principles and human sex roles

Abstract

In 1948, Angus J. Bateman reported a stronger relationship between mating and reproductive success in male fruit flies compared with females, and concluded that selection should universally favour 'an undiscriminating eagerness in the males and a discriminating passivity in the females' to obtain mates. The conventional view of promiscuous, undiscriminating males and coy, choosy females has also been applied to our own species. Here, we challenge the view that evolutionary theory prescribes stereotyped sex roles in human beings, firstly by reviewing Bateman's principles and recent sexual selection theory and, secondly, by examining data on mating behaviour and reproductive success in current and historic human populations. We argue that human mating strategies are unlikely to conform to a single universal pattern.

Figure 1

(a) The ratio of male to female variance in reproductive success varies significantly with mating system (Kruskal-Wallis, χ-squared = 9.09, df = 2, p = 0.011). Analyses were carried out on dataset from the monogamous (N = 6), serially monogamous (N = 3) and polygynous (N = 9) populations shown in Table 1. Post hoc analyses revealed that the ratio was significantly higher for polygynous populations than monogamous populations (*=p < 0.017 using Mann-Whitney U test). No other pairwise comparisons were significant. (b) Lifetime reproductive success of the monogamous Pitcairn Islanders, Pacific Ocean (re-drawn, with permission, from Ref. [82]). A Levene's test indicates that male and female variances are not significantly different (t = –0.15, n.s.). (N = 145 males and 127 females.) Individuals with zero offspring are not shown in the graph (N = 60 males and 47 females). (c) Lifetime reproductive success of the highly polygynous Dogon of Mali (re-drawn, with permission, from Ref. [92]). A Levene's test indicates that variance in male reproductive success is significantly higher than variance in female reproductive success (t = –3.36, p < 0.01). (N = 44 males and 48 females >42 years of age). (d) Lifetime reproductive success of the mildly polygynous Aka of the Central African Republic (re-drawn, with permission, from Ref. [87]). A Levene's test indicates that male and female variances are not significantly different (t = –1.32, n.s.). (N = 29 males and 34 females >41 years of age.) Colour code for parts (b–d): red bars, males; yellow bars, females. Abbreviations: n.s., not significant.