Impairment in a child's ability to be able to play in a way that involves peer collaboration. Collaborative play involves things such as verbal and non-verbal communication (e.g., self-initiated interactions), turn-taking, sharing, reciprocity, and collaborative problem-solving. It is often contrasted to parallel play, which involves a form of social play in which two children do similar activities near each other and often mimic each other. Typically developing children develop collaborative play between the ages of 4 and 5. [from
HPO]