Interesting note on psychopathy: the scope and definition of the term has narrowed over time. The term used generally in the past today would be anti-social behavior, with psychopathy as an extreme.
But again, AFAIK these behaviors are all caused by:
1) group differences in neoteny (Pedomorphism) and
2) group differences in sex (body) gender(mind) dimorphism
3) group differences in class size, and
4) reinforcement by ingroup norms.
5) because of the discount and returns on ingroup association
In other words, our groups mature at different rates and depths, with greater.