State Dependent Behavioral Theory and the 1 Evolution of Play

18 We show how state dependent behavioral theory, as implemented by Stochastic Dy19 namic Programming can enhance our understanding of play, assuming that play is an 20 evolutionary adaptation rather than a non-functional consequence of other processes. 21 We first explain in generic terms the components of a state dependent behavioral model. 22 We then develop a state dependent life history model on the assumption that social play 23 is adaptive and thus focus on play’s contribution toward the development of skill and 24 how such development affects an individual’s future lifetime expected reproductive suc25 cess (i.e. fitness that accounts for both survival and reproduction). Although our model 26 is not intended to capture a specific situation, a number of commonly observed phenom27 ena emerge from the model, including that most social play is dyadic and that animals 28 select partners that are of similar age or skill. We discuss ways of increasing the fidelity 29 of the model by allowing for injury due to play, the role of energetic reserves, handi30 capping, and for polyadic play. 31 32