One thing I'll be studying during the summer is the beginnings of uncovering the randomness of behavior. Usually these non-heritable changes are chalked up to the "environment." Some can be accounted for and others cannot. There are examples in nature of identical genetics and only minimally different upbringing that manifests as huge differences.
I wonder if anyone has done a study to see if there are genetic features of people that exhibit this behavior. If not, it would be cast into the environment category as being the explanation. Is this random though or learned?