Ben Thomas Gleeson1, Geoff Kushnick2. 1. Fenner School of Environment and Society, The Australian National University, Canberra, Australia. 2. School of Archaeology and Anthropology, The Australian National University, Canberra, Australia.
Abstract
OBJECTIVES: Humans exhibit multiple anatomical and behavioral signatures of domestication syndrome, leading evolutionary-minded scholars to suggest Homo sapiens is a "self-domesticated" species. We examined one of three mechanisms proposed to explain human self-domestication-that is, intersexual selection against reactive aggression. We hypothesized that this process has been, at least in part, caused by context-dependent female preferences for less-aggressive males. We predicted that societies where women have higher social status will show relatively elevated signs of self-domestication-as indicated by lower stature sexual dimorphism (SSD)-and that this relationship should be mediated by food security. MATERIALS AND METHODS: To test our prediction, we used male and female stature data for 28 societies from the Standard Cross-Cultural Sample. We applied multivariate regression to examine our hypothesis while controlling for theoretically important confounders. RESULTS: We found convincing support for the prediction that the relationship between SSD and female status is mediated by food security. As predicted, higher female status was associated with less sexual dimorphism and the effect is stronger when food resources are secure. DISCUSSION: Context-dependent female mate choices significantly contribute to lower SSD, suggesting female mate choice is likely to have played an influential role in human self-domestication. Future research on this theme will benefit by including more of the expected symptoms of human self-domestication and examining other potential drivers of this process.
OBJECTIVES:Humans exhibit multiple anatomical and behavioral signatures of domestication syndrome, leading evolutionary-minded scholars to suggest Homo sapiens is a "self-domesticated" species. We examined one of three mechanisms proposed to explain human self-domestication-that is, intersexual selection against reactive aggression. We hypothesized that this process has been, at least in part, caused by context-dependent female preferences for less-aggressive males. We predicted that societies where women have higher social status will show relatively elevated signs of self-domestication-as indicated by lower stature sexual dimorphism (SSD)-and that this relationship should be mediated by food security. MATERIALS AND METHODS: To test our prediction, we used male and female stature data for 28 societies from the Standard Cross-Cultural Sample. We applied multivariate regression to examine our hypothesis while controlling for theoretically important confounders. RESULTS: We found convincing support for the prediction that the relationship between SSD and female status is mediated by food security. As predicted, higher female status was associated with less sexual dimorphism and the effect is stronger when food resources are secure. DISCUSSION: Context-dependent female mate choices significantly contribute to lower SSD, suggesting female mate choice is likely to have played an influential role in human self-domestication. Future research on this theme will benefit by including more of the expected symptoms of human self-domestication and examining other potential drivers of this process.