[POS] Ecology and Enviromment

[POS-44] Evolutionarily stable learning schedule when information is transmitted between non-kin in social learning

*Motohide Seki¹ (1. Kyushu University (Japan))

Keywords:

social learnig,individual learning,cumulative cultural evolution,life history,evolutionarily stable strategy

Human culture is characterized by the accumulation of information over generations, which would be the combined result of individual learning (IL) and social learning (SL). Theoretical studies focusing on the cumulative cultural evolution have indicated that there is an optimal learning schedule. According to this schedule, an individual first imitates the behavior of individuals in the parental generation, namely SL, during their infant period. Then, in the juvenile period, the individual adds novel information foud by IL. The majority of those studies implicitly assumed that a model (imitatee) and a learner (imitator) in every SL oppotunity are close kin. However, SL can occur between individuals that are not related to one another, in which case the model contributes the fitness of the non-kin learner. In the present study, I extended the mathematical model of Lehmann et al. (2013, Evolution 67:1435–1445) by assuming that information possessed by an adult individual is unavoidably transmitted to non-kin infants observing that adult. Consider species life history of which consists of at most four stages, infant, juvenile, reproductive, and post-reproductive stages, which last for K, L, M, and N time units, respectively. An individual, after birth, engages in SL and IL in the infant stage and the juvenile stage, respectively. It accumulate resource for reproduction in the reproductive stage. Reproduction occurs between the reproductive and post-reproductive stage. Then it provides parental care to its offspring until the end of the post-reproductive stage. Behavior of the post-reproductive individual can be imitated by any kin and non-kin infants. The number and survivorship of offspring of an individual is positively associated with the amount of information it acquired by SL and IL. Using the model, it was examined whether a specific life history strategy {K, L, M, N} was evolutionarily stable or not against invasion by a mutant following a slightly different strategy {K + ΔK, L + ΔL, M + ΔM, N - ΔK - ΔL - ΔM}. The analytical and numerical result indicate that there is a single evolutionarily stable (ES) life history. If the total lifespan is sufficiently long or if the transmission efficiency of information in SL is sufficiently high, the ES life history includes the infant and post-reproductive stages. The lengths of these stages are shorter when information is transferred between non-kin than when the transfer is limited to kin.