Coevolution of life history and culture.

Social learning, by which an individual acquires pieces of information carried by neighbouring individuals, is often considered to provide lower cost than individual learning does, and thus it is a kind of free-riding behaviour. I examined evolutionary stability of life history with vertical or oblique cultural transmission, where an infant individual "copies" useful information of his/her post-reproductive parent or a random individual from the parental generation. I found that evolutionarily stable length of the infant stage monotonically increases with increasing information transmission efficiency under vertical transmission, whereas it is a one-humped and non-smooth function of the efficiency under oblique transmission.