Something to understand about Sociopathy/Psychopathy/ASPD is that your mental model has been effected by selection bias (also availability bias). The only ASPD people you hear about are those with problems. The ones you hear about do not just have ASPD. ASPD magnifies other problems, be they biological, social, or circumstantial.
ASPD + Conduct Disorder causes the type of psychopathic serial killers popular culture is familiar with. ASPD + a brilliant mind and educational opportunity means you'd make a great lawyer or CEO. A guy with ASPD who gets addicted to drugs is more likely to rob or steal to get a fix. A guy with ASPD who sells used cars is more likely to be a great salesman because he pushes for the sale even when it's against the interest of his customers. A gang member with ASPD is more willing to use violence or kill for the gang. etc.
People can go their entire lives without finding out that they've got ASPD, let alone others finding out. The problem with Psych statistics is that they can't get a cross section of the population; they can only infer from the subset of people who need psychological help. It's textbook selection bias.
To go into analogy mode, think of humans as web browsers. A normal, functioning human is Internet Explorer 9; it receives the information and acts on it the way you'd expect. An autistic human would be an out of spec browser from 1992; it tries it's best but it can't render everything right and doesn't quite know what's going on, even though it would like to. A human with ASPD is like Firefox with the Adblock addon; it knows exactly what the website wants it to do and exactly what's expected of it, but it refuses to render or be effected by advertisements. If you've got other addons (mental disorders) though, the interaction between the two will make the browser more likely to catastrophically fail.
A normal, functioning human is Internet Explorer 9; it receives the information and acts on it the way you'd expect.
I was going to say this is a bad example, since IE9 still doesn't handle a lot of things the way it ought to, but humans are crazy the world is insane so whatevs.
I have consistently, over the course of my life, heard people describe sociopathy and related mental illnesses as being caused by a lack of empathy. This, intuitively, seems wrong, since that seems like a massively important brain function, that really ought to have a major and extremely visible effect on your thinking. Now, obviously it does have a serious impact (amoral behavior, etc), but it seems rather unlikely to me that someone like this really shouldn't be able to mask themselves as normal. (I'm also not sure why lack of empathy would make you want to dissect squirrels, but that seems like a side issue).
The upshot is that I'm seriously confused about what these mental disorders are, and how they work. Do these individuals have the ability to empathize but not sympathize? I'm not sure how that would work, but I'm not at all an expert on cognitive science. Is the standard explanation for these disorders just wrong? Are these people genuinely figuring out what humans care about by looking?
(As a side note, if it's the last one, has anyone considered getting a sociopath to work on FAI? Bringing someone who can't be trusted into an enterprise is a risky move, but if there genuinely are people in the world who have spent their entire lives practicing working out human emotions without feeling them...)