Do the aged and knowledgeable men enjoy more prestige? A test of predictions from the prestige-bias model of cultural transmission

The propensity to imitation over other forms of learning is one of the major differences between humans and other species and one that has allowed for cumulative cultural evolution. However, imitation alone cannot explain increases of average fitness in human populations. Anthropologists have hypothesized that people do not imitate behaviors from random people; rather, transmission of some cultural traits (e.g., healing skills) follows biases designed to extract reproductive benefit from the flow of socially transmitted information. In an article in this journal, Henrich and Gil-White argued that important sources of bias in the acquisition of culturally transmitted information come from prestige processes. Here, we test predictions from the prestige-bias model of cultural transmission. We use quantitative information on ethnomedicinal plant knowledge of adult (age >16) Tsimane' men (n=288) collected during 2005. To measure prestige, we asked Tsimane' to list important villagers and counted the number of nominations each person received. We find weak evidence that prestige is associated with ethnomedicinal plant knowledge, and we find no evidence that prestige is associated with age. Rather, we find a secular decline in prestige by decade of birth. Last, prestige bears a positive association with other attributes, such as participation in village organizations. Future empirical research needs to decouple power from prestige.