Social networks show striking structural regularities 1 , 2 , and both theory and evidence
suggest that networks may have facilitated the development of large-scale cooperation in …

Many human behaviors, from mating to food acquisition and aggressiveness, entail some
degree of risk. Testosterone, a steroid hormone, has been implicated in a wide range of such …

… Interviews were conducted privately, in Swahili, by CL Apicella with the help of a Tanzanian
research assistant. Each participant was asked to provide the names of all children born to …

Humans and many non-human primates exhibit large sexual dimorphisms in vocalizations
and vocal anatomy. In humans, same-sex competitors and potential mates attend to acoustic …

Individuals exhibit substantial heterogeneity in financial risk aversion. Recent work on twins
demonstrated that some variation is influenced by individual heritable differences. Despite …

Many studies show agreement within and between cultures for general judgements of facial
attractiveness. Few studies, however, have examined the attractiveness of specific traits and …

Background Many animals both display and assess multiple signals. Two prominently studied
traits are symmetry and sexual dimorphism, which, for many animals, are proposed cues …

… The participants in this study were 170 adult males recruited by one of the authors (Apicella).
About 75% of the men were recruited from London's Heathrow Airport and a major train/…

The endowment effect, the tendency to value possessions more than non-possessions, is a
well-known departure from rational choice and has been replicated in numerous settings. …

In humans, voice pitch is thought to be a cue of underlying quality and an important criterion
for mate choice, but data from non-Western cultures have not been provided. Here we test …