Nonlinear Dynamics, Psychology, and Life Sciences, Vol. 18, No. 3, pp. 251-276. © 2014 Society for Chaos Theory in Psychology & Life Sciences Collaborative Play in Young Children as a Complex Dynamic System: Revealing Gender Related Differences Henderien Steenbeek 1 , University of Groningen and University of Applied Studies, Groningen, the Netherlands, Diny van der Aalsvoort, Saxion University of Applied Sciences, the Netherlands, and Paul van Geert, University of Groningen, the Netherlands Abstract: This study was focused on the role of gender-related differences in collaborative play, by examining properties of play as a complex system, and by using micro-genetic analysis techniques. A complex dynamic systems model of dyadic play was used to make predictions with regard to duration and number of contact-episodes during play of same-sex dyads, both on the micro- (i.e., per individual session), meso- (i.e., in smoothed data), and macro time scale (i.e., the change over six consecutive play sessions). The empirical data came from a study that examined the collaborative play skills of children who experienced six twenty minute play sessions within a three week period of time. Monte Carlo permutation analyses were used to compare model predictions and empirical data. The findings point to strongly asymmetric distributions in the duration and number of contact episodes in all dyads over the six sessions, as a direct consequence of the underlying dynamics of the play system. The model prediction that girls-dyads would show longer contact episodes than boys-dyads was confirmed, but the prediction regarding the difference in number of peaks was not confirmed. In addition, the majority of the model predictions regarding changes over the course of six sessions were consistent with the data. That is, the average duration and the maximum duration of contact-episodes increases both in boys-dyads and girls-dyads, but differences occur in the strength of the increase. Contrary to expectation, the number of contact-episodes decreases both in boys-dyads and in girls-dyads. Key Words: collaborative play, gender differences, micro genetic analyses, dynamic modeling, complex dynamic systems approach, intra-individual variability INTRODUCTION Collaborative play is a major developmental task as children become part of a classroom and school community (Fantuzzo et al., 1995; Lutz, 1 Correspondence address: H. W. Steenbeek, Heijmans Institute, University of Groningen, Grote Kruisstraat 2/1, 9712 TS Groningen, the Netherlands. E-mail: h.w.steenbeek@rug.nl 251