Psychopaths and sociopaths are two different animals in this regard. Psychopaths often display tendencies before the age of 7, despite rearing. Sociopath is closer to a 'choice', given a certain biological component, while psychopath are far less so. Often, serial killers come from normal childhoods/backgrounds [eg Ted Bundy, Jeffrey Dahmer, Eric Harris, Richard Storlett, Paul Bernardo, Cary Staynor, et al] with no evidence of abuse. This article has a good description of the topic with reference to the nature/nurture debate above. It is still alive and well, although it is no longer either/or (and shouldn't be).
From another article:
It is also appears that the causes of psychopathy and sociopathy are quite different. It is likely that psychopathy is the result of “nature” (genetics) while sociopathy is the result of “nurture” (environment). According to the late David Lykken, a behavioral geneticist known for his studies on twins, psychopathy is related to a physiological defect that results in the underdevelopment of the part of the brain responsible for impulse control and emotions. Sociopathy, on the other hand, is more the product of childhood traumas and abuse. [LINK]
There's a strong biological strong component to psychopathy, and often rearing makes absolutely no difference. The parts of the brain requiring normal function just aren't there (do not work).
In the past several years studies of brain activity in individuals meeting the criteria for psychopathy have yielded some groundbreaking findings. CAT scans reveal that with psychopaths, areas of the brain typically associated with emotion, especially the integration of emotion with other mental constructs, do not operate in the same manner as they do with normal individuals. Show most people a picture of something typically associated with a sentiment (e.g., a wedding ceremony), and areas of the brain that process information about the event as well as areas of the brain involved in emotion both show activity. But show the same image to a psychopath, and although the area of the brain recognizing the image or event is active, the area of the brain typically associated with an emotional response appears dormant. Other brains studies measuring different aspects of the integration of emotions with other human experiences have shown the same abnormalities when it comes to psychopaths.
Very interesting discussion.
We're going to need to establish exactly what you mean by psychopathy. We're not just talking about serial killers here. List off psychopahic qualities, and we can look into each one from a nurture/nature standpoint. Regardless, that was just a kind of side point not really related. I think this was mainly environment and experience. I'm not excusing him from responsibilty; but at the end of the day, nobody chooses their genes, parents, peers, experiences, etc. If it's as biological as we are learning it may be, calling AH scum is, to me, like asserting his soul (assuming there is one) went gene shopping, and explicitly picked out sociopathic genes.
All I've been saying is that in the case of AH, who seems more a sociopath than psychopath (lending credit to my points, btw), there are classic markers. Superimpose on to that what we know about the developing teenage brain.