An alternative answer to this question that has so far received little attention is the possibility that psychopathy may be an instance of what scientists colloquially refer to as a zombie idea: ideas that have the quality of being intuitively appealing, but the idea itself is essentially a fallacious misconception of reality. Just like zombies, when these ideas have been falsified – shown to be dead ideas – they somehow still manage to stubbornly stick around in the halls of prestigious universities, only to once again infect another generation of young scientists.

There are many historic examples of zombie ideas, such as phrenology, race theory, or the geocentric view of the Universe. What these ideas have in common is that they were all widely accepted by scientists, even for decades after they were thoroughly refuted by scientific research. And this gets to the core of a zombie idea: those who are infected always fail in the strangest ways to realise that the idea is dead. As such, zombie ideas appear to be upheld by strong biases where the idea itself is rarely questioned, even when the scientist who believes in them is faced with obvious evidence that suggests the idea is wrong. Fortunately, zombie ideas are relatively rare in the sciences, but they truly are a peculiar phenomenon.