THIS DOESN’T SHOCK ME: Psychopathy might be a trait, rather than a mental disorder. “Psychopathy can at once be unwanted under one set of circumstances and prized in another, without invoking models of disease. It can be both an alternative strategy to survival, helping in some social contexts before becoming a disorder in another.”

It may even be adaptive for a group to contain some psychopaths — they’re destructive internally to the group, but may also be highly valuable in conflict with other groups. That said, this study doesn’t seem super strong to me.