We all assume psychopaths are murderers, but actually the psychopaths who have been the product of abusive/neglectful upbringing turn into the rose wests. The well brought up psychopaths turn into ceo's.
And racing drivers, fire fighters, rescue divers, all sorts. Anything where feeling empathy too deeply and caring too much about risk or other people is a problem.
My favourite psychopathy fact is about eyes. Pupillary response and startle response in psychopaths differ from typical. If you show people the following then both measure their dilation and puff some air in their eye:
A. Nice images (puppies/people smiling)
B. Neutral images (a table/a Hoover)
C. Nasty images (and eye hanging out/well you can imagine)
Generally our pupils dilate when we are emotional and our startle response increases the nastier something is. So a normal person would dilate for A and C and startle for B a little more and C a lot more. A psychopath would dilate ONLY for A and startle more for B than A or C.
Which could mean it's not that they can't process emotion. Rather that they process negative emotions more like the rest of us process positive. They process positive the same way we all do. And that could mean that putting psychopaths in positive, happy environments is very important, far more than for the rest of us.
TL:DR if you think someone is a psychopaths, watch a horror film and blow in their eye.