Sociopathy is a personality disorder which is still under study. There are a list of traits you can look up online which have been gathered from analyzing prison populations. It includes everything from lack of empathy, to glib, superficial charm, high risk taking, the inability feel guilt, etc. These lists don't necessary describe the population of individuals skilled enough at their self-interest games to avoid prison.
1. There may be damage in the amygdala and frontal cortex since some research has shown this.
James Fallon, psychologist, pro-social sociopath
2. There is also psychological theory that describes the anti-social personality disorders occurring during the infant/toddler process of moving from a concept of only Self to that of Self and Other. When infants are left isolated, neglected, and harmed, then they get stuck at a very early psychological age emotionally, but with the added abstract reasoning of an adult. If you can imagine the two-year-old rebellion of "MINE, MINE" "NO!" throws toys, screams, pulled mother's hair and kicks, then add pure, reasoned analysis and the ability to analyze and predict behavior and outcomes in other individuals, then you know what it is like to interact with someone with a personality disorder. I will add that some individual are sophisticated enough in their harm to not hit and scream, but rather use manipulation and passive aggression to cause harm and achieve their goals. Those are the ones who aren't in prison.
There is an entire category of these disorders that are based on extreme investment in Self with obliviousness to Others. These include sociopathy, narcissism, borderline personality disorder, and psychopathy (which is a term that hasn't been used as much recently from what I understand).
These are the two theories of this condition: one based on nature, and the other nurture. I suspect there is a lot of reciprocation between the two.