Overimitation begins in infancy but is not yet linked to in-group preference

Humans are by nature social creatures, far more so than other primates. Our desire to be accepted by our in-groups is universal and innate.

It also comes early: multiple studies have demonstrated how preschool-age imitation of adult behaviour leads to acquiring new skills, sharing cultural knowledge and fostering a sense of affiliation. One form of this behaviour is overimitation -- the tendency to copy actions that are not necessary to achieve a goal.

First reported by ScienceDaily: Relationships.