I wrote about DV as an example of taxonomies some time ago.
Antisocial Personality Disorder and Narcissistic Personality Disorder are both different, but they get to the same place, seeing people as tools or toys to be used. And the old saw that "there are many paths to the top of the mountain" ignores the fact that there are actually many mountains, with many different points of view and the path you choose will change how you see the view more than the elevation.
I do believe some people are born unable to see that other people are real. It's an emotional thing and there is a sliding scale to it. At the extreme end, this is like a video game and other people are just pixels. Slightly less intense, many criminals don't feel shame. They just don't get it (See Fleisher's Beggars and Thieves for some corroboration). About half of my friends feel "trust" as an emotion and the others see it as a decision, but with no feeling associated. Which leads me to believe that it is probably possible to scale people's emotional palette.
That was a bit of an aside.
I believe some people are born sociopaths, and essentially don't have the capacity to develop an emotional palette that includes compassion or empathy. I believe a larger number have the capacity but it was never developed-- Babies are born inherently selfish and egocentric and must be taught that other people have feelings just like them. If that teaching fails, the child will be heartless. Sociopath? Functionally, but a very different mechanism.
And one can be placed in an environment where heartlessness is the only effective survival strategy. Humans are adaptable, and even people who will not be heartless on their own behalf can become heartless if that is the only way to protect or feed their children. It's rare, fortunately, and almost all of society is set up to prevent this. And the older and more entrenched you might be in your early socialization, the harder it will be to actually act... but in an environment where ruthlessness is necessary to survival, the survivors will be ruthless.
So, rambling as that was, three ways to get to almost anything. And none of those three ways are separate, they all interact:
Nature, socialization and selection.
- If you have a genetic gift, you can be very fast.
- If you are raised in a society where speed is rewarded and slowness punished, your childhood games will be based on developing speed. You'll be faster than someone with similar genetics raised differently.
- And if all the slow kids die, the surviving kids will be fast.
For fighting or combat or making friends-- some have the right genetic mix of physical and mental attributes. Some learned. And some adapted because they had no choice.
For good things and bad things. That has a lot of implications for us as trainers, voters, people. It's not a single lens, not one size fits all. Do we want to train survivors? Selection doesn't do that, it weeds out the ones who need training most. Do we want to fix crime or any social problem? Eugenics, education and social welfare are three historic attempts to do that, each aimed at one of the three paths.