Distance to innovations, kinship intensity, and psychological traits.

Psychological traits display substantial variation worldwide. These psychological variations could be explained by the intensity of kinship ties which, we hypothesize, depends on the reception of innovations that gradually complexified family organizations. These innovations originated from several centers across the world that also spread other crucial novelties such as agriculture. Less exposed to these family innovations, areas far from centers of innovation should exhibit lower kinship intensity. Indeed, we show that distance to innovation centers is strongly associated with kinship intensity. This distance is also associated with psychological traits especially outside Western Europe in which exposure to the Church seems to play an additional role.