- Psychopathy in chimpanzees can be defined by their levels of meanness, boldness, and lack of restraint.
- Research shows that chimpanzees display psychopathic behaviour in its purest form because they are free from the social shackles of humans.
- Studying non-human primates is helping us to better understand mental illness.
Psychopathy is broadly defined as persistent antisocial behaviour, and having no sense of empathy or remorse.
In the past, psychologists have been in some disagreement over the specific scope and boundaries of the disorder, but a few years ago, the Triarchic model was created to explain the traits of a psychopath: Boldness, meanness, and disinhibition.
Current research puts the reasons for being a psychopath in both the nature and nurture camps. This means a psychopath could be born or made depending on their upbringing, genes, or a mixture of both.
As well as in-depth study of people with psychopathy, animal models can actually be helpful in trying to make these causes clearer too.
Neuroscientist Robert Latzman, a clinical psychologist by training and a professor at Georgia State university, has worked with children and adolescents for much of his career. Recently though, he has shifted his focus to study the behaviour of chimpanzees.
Latzman and his team have been looking at the personality traits of psychopathy and whether they occur in chimpanzees. In a new study, published in the journal Frontiers of Neuroscience, they worked with 164 chimpanzees, and asked their handlers to give them personality ratings on the “CHMP-Tri scales,” which scored their level of psychopathic traits.
The history of the chimpanzees was known to the researchers. This meant the team knew who was related to who, and could, therefore, assess whether certain traits ran in families.
“Consistent with findings in humans, recent work in our lab has found that psychopathic personality traits are heritable — that is, genetics matter,” Latzman told Business Insider.
“What we know less about, though, is what the specific genes are. We, therefore, started our search in an area typically of interest in regards to social behaviours — the vasopressin system.”
Vasopressin is a hormone known to play a part in our complex social behaviours. The team looked specifically at whether variations in genes associated with vasopressin had an impact on how psychopathic personality traits manifested themselves in chimpanzees — and it does.
However, the vasopressin hormone certainly isn’t a “psychopath gene.” Latzman says it is a tiny part of a massive, highly convoluted picture.
“We are hanging our hats on very small hooks if you will,” he said. “We are explaining relatively small amounts of the variance here. It’s going to be a much more complicated story than a single gene or neuropeptide system.”
Why chimpanzees are great for research
Psychologists have been doing a lot of research into psychopathy — what makes a psychopath, whether there are biological markers for the disorder, or whether it can be prevented or cured.
There are always limitations with the results from animal models being translated to humans, so I asked Latzman why he chose to work with chimpanzees at all.
“You can investigate behavioural or emotional processes that are not just similar but parallel to processes seen in humans, and then also consider neurological or biological processes that are also parallel between humans and chimpanzees,” Latzman explained. “Chimpanzee models further allow us to largely remove socio-cultural factors from the equation resulting in accounts more closely rooted within biology.”
In other words, they display behavioural issues in their purest form because they don’t have to bother with the social pressures of humans. Chimpanzees are never taught they have to share, they don’t have to be nice to each other, and they don’t have to say sorry or wait for their turn.
In humans, any number of different social factors could affect the outcome of someone’s personality. In chimpanzees, all these outside forces can be monitored.
Primates are helping us better understand mental illness
Other research institutes also use non-human primates to study different behavioural disorders. For example, a study of rhesus monkeys from the University of Wisconsin showed how the risk of developing anxiety and depression is passed down from parents to children.
Brain imaging technology helped identify the regions of 600 monkeys’ brains that were responsible for passing anxiety from generation to generation, and the results showed that 35% of anxiety-like tendencies could be explained by family history.
Latzman told Business Insider that research like this is important because it could one day define what it is that makes people end up with mental health disorders in the first place. It could also potentially prevent such things happening.
Also, the way we diagnose personality disorders is changing. Whereas we are used to being given a diagnosis, Latzman says psychology is moving past the idea that either you “have” something or you don’t.
For example, if someone is being tested for type 1 diabetes, a doctor can determine whether the patient has it or not by looking at the insulin production in the pancreas. There is no blood or lab test for psychiatric disorders — it’s a matter of the extent to which they are presenting certain traits.
“To use depression as an example, it’s not a matter of having or not having it, it’s the degree to which you have specific symptoms, in addition to impairment, that results in something like a diagnosis in depression — it is not something you have or don’t have like some other medical diagnoses,” Latzman said.
“A more dimensional understanding of mental illness, understanding that mental health falls along a continuum, will help us improve our understanding of the the way in which people suffer. Because at the end of the day, this work is all in service of better understanding the development and persistence of suffering and how best to alleviate this suffering.”