Are we all descended from psycopaths in the far distant past. In a dog eat dog world of survival, such as our ancient cave dwelling ancestors live, who would have been the ones to most successfully thrive and breed? I think the psycopaths, I don't think we would have descended from the meek - they would have been pushed aside.

Currently psychopaths make up 1% of the population - was it 100% 20,000 years ago?

If the world suffered a total catastrophe (CME, pole reversal, asteroid strike, super plague) and most of the population died off, would the percentage of psychopaths go up radically?

Who is more fit for survival in a dog eat dog (man eat man?) world - the people with no empathy or sympathy or the people with empathy and sympathy?