Somewhere in the the past I saw a study talking about a type of ape that raises it's young in creches, unlike chimpanzees which at most carefully choose occasional babysitters. The study made the case that the apes with young in creches had more mirror neurons, and learned though mimicry more easily than chimpanzees, despite lower overall intelligence.
Haven't been able to find the study and it seems there are now some divergences in opinion about the function of mirror neurons. What I would really like to know is, is there evidence around child-rearing environments and mirror neuron development, and the impact of that in adult behaviour? In humans or across species is fine.