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:
- group differences in neoteny (Pedomorphism) and
- group differences in sex (body) gender(mind) dimorphism
- group differences in class size, and
- reinforcement by ingroup norms.
- because of the discount and returns on ingroup association
In other words, our groups mature at different rates and depths, with greater.