Between-sex differences appear during a limited window of development and even change direction with age. Children's social play showed important changes during the preschool period, becoming more peer-oriented and structured with age Fig. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Preschool boys also display more solitary play than preschool girls, especially when young. ZhenyaJaneSalop 2 years ago Same. Among available peer play scales, we adapted the seminal Parten's [32] framework which covers the social spectrum of children's participation in peer play, with non-social activities: