In a recent article in the Economist, the author snappily opens with “What makes people psychopaths is not an idle question. Prisons are packed with them.” The claim that prisons are filled with psychopaths depends on the faulty inference that because criminals are in prisons, and psychopaths commit criminal acts, there should be lots of psychopaths in prisons. We don’t actually know that, and there are reasons to think otherwise. In the United States over two million people are incarcerated, and over twenty percent of State prisoners and over fifty percent of federal prisoners are there because of irrational recreational drug laws. Perhaps the legislators who wrote these laws are psychopaths for being willing to lock up innocent people for no good reason in order to hold political office. I don’t think that we can infer that only a psychopath would violate drug laws. Second, there is socialized criminality, criminality which is socially normative for a subculture. Here, the criminal actually becomes such because of their responsiveness to the social norms of their community, it’s just that the rest of us are at odds with that community (gang, mafia family). What is wanted there is less socialization, not more. Third, there is some reason to think that the violent are victims of head trauma, with consequent effects on impulse control, and these people are neither psychopaths nor hereditarily predisposed to anything (as far as we can tell there is no gene predisposing you to head trauma).
Discovering that someone who has committed a crime has brain damage does not mean a wholesale abandonment of our notions of moral agency and responsibility, because those notions do not require any magical causation incompatible with naturalism. What is needed here is an appreciation of how contextual factors contribute to our causal judgments. If a perfectly flat and level pool table (analogy: medically normal brain) is the site of a missed shot at the corner pocket, we talk about the player’s skill (analogy: moral agency), not the gravitational field of the planet. But if the shot would’ve gone in but for a bump in the table (analogy: brain damage) we attribute the trajectory to the bump. To say that unless there are magical forces involved, there are no such things as skillful shots is a confusion. And one need not be an incompatibilist-determinist to find Spinoza’s psychological account of the punitive impulse plausible, and troubling. As long as our own moral agency is intact, we have an obligation to get these things right, and not just follow our feelings.
In general, evolutionary psychology is a useful tool if used with care, which, increasingly, it is not. When it isn’t, the result is Just So Stories which get the rest of us off the hook for coming to grips with the real moral complexities and perplexities that face us. I suspect that an awful lot of people are incarcerated because we are just too lazy to find out why they did what they did, or make the difficult choices that such knowledge would require. Meanwhile, the real psychopaths, who may very well be Darwinian parasites on the social, make their way among us. But they’re not in hidden away in your prisons. They’re on TV, right in front of your nose.