Psychopathy is a poorly understood phenomenon. It used to be thought of as exclusively psychological, but it’s increasingly looking like it’s partly neurological in origin, in that the brains of psychopaths are wired differently. It’s not even very well defined – it involves a range of behaviors, not just one – and certainly doesn’t mean someone is necessarily “crazy.”
With all this confusion, it makes sense that researchers are now turning to chimpanzees, our most closely related fellow apes, to understand psychopathy better. Chimpanzees are free of human societal constraints, and as such, they represent a model study for the innate nature – or lack thereof – of psychopathy.
As reported by the British Psychological Society, recent work on our evolutionary cousins suggests that there’s a clear genetic basis for psychopathy.
A Georgia State University-led team carefully observed 164 of these primates housed at two research centers, one in Atlanta and another run by the University of Texas. Two or three handlers were assigned to each chimpanzee, with the requirement being that they knew them well.
Assessing psychopathy in humans is normally done via a psychological evaluation, and sometimes using magnetic resonance imaging (MRI) scans on the brain. The way people describe their normal behaviors and proclivities, and the flow of blood in the brain to and from the amygdala – the “fear center” – are often good ways to see if people have psychopathic tendencies.
This is not so easily achieved in chimpanzees, who aren’t known for being particularly conversational or happy to sit in extremely noisy MRI scanners. Amazingly, there exists something called the CHMP-Tri scale, a sort of personality test specifically designed for chimpanzees.
This scale looks for callous aggression, and lack of restraint, and propensity towards bold behaviors. All these are suggestive of psychopathy, and these can be observed without needing to ask the chimpanzees any direct questions.