Emergent Structure in Children's Play Group Formation
William A. Griffin**, Willa Cree, M.S., Carol Martin, Ph.D., Richard Fabes, Ph.D., Laura Hanish, Ph.D


     In the fall of each year, new and returning children between the ages of 3 and 6 are brought together in Arizona State University's Child Development Lab where they eventually settle into pods of stable play partners.  Factors contributing to the formation of these play groups are currently unknown but the dynamics of this evolution appear to have similar characteristics as other structures in social organizations (e.g., agent actions appear to be rule-based).  This setting provides a natural laboratory of studying emergent structure.  Each year, the lab has a slightly different social environment, this difference results primarily from the play group formations, and in turn, play group formations are derived from the stability of who plays with whom.  These groupings and the structure they impose on the lab evolve as the year progresses.  The purpose of the paper is to model this evolution.  We examine the role of individual child attributes on the emergent behavior.  We use four child attributes derived from behavioral observations: Physical attractiveness, Prosocial behavior, Aggression, and Activity level.  Using these attributes along with gender, we simulate the propensity of a child, with a given set of attributes, to play with any other given child.  We include gender in the model because strong gender typing in children of this age group appears to act as a primary deterrent or facilitator in determining reinforcement by peers.  We illustrate the correspondence between simulated play clusters based on child attribute vectors and actual data obtained at several fixed points throughout the school year. Differences at each iteration provide information about the possible strategies children may be using to select play partners.  In turn, we interpret these strategies and resign the simulation; by, for example, differentially weighting attributes.  Preliminary modeling suggests that gender may mediate the effects of social attributes.