When do associative and cooperative play typically become most common in children?

 Associative and cooperative play are stages in the development of play in children. Associative play typically becomes most common around the ages of 3 to 4 years. At this stage, children start to interact more with each other during play, but they do not necessarily work towards a common goal or follow a set of structured rules together. They may engage in similar activities side by side and even exchange toys or comment on each other's behavior, but their play is still primarily organized according to their individual goals.

Cooperative play usually emerges around the ages of 4 to 5 years and continues to develop as children mature. This is when children start to play together with a shared aim. They may work together to build something, play games with rules, or engage in role-playing that involves coordination and negotiation. At this stage, children are interested in both the activity and the social interaction that comes with it, indicating more sophisticated social skills and an understanding of teamwork and cooperation.