Brain scans of 49 criminals predicted how many crimes they had been convicted of.
Psychopaths are not ‘aliens’, but people who make bad, short-sighted-decisions, argues a Harvard neuroscientist.
They are everyday human beings whose brains are wired differently to the rest of us.
Just how differently is revealed in a new study published in the journal Neuron.
The study found that psychopaths:
- focus mostly on reward,
- and don’t think much about the consequences of their actions.
This is quite different to most people whose natural response is to consider:
- what they can lose above what they can gain,
- and what the consequences will be of their actions.
For the research, Dr Buckholtz and colleagues scanned the brains of 49 prison inmates.
Dr Josh Buckholtz, explained:
“For years, we have been focused on the idea that psychopaths are people who cannot generate emotion and that’s why they do all these terrible things.
But what what we care about with psychopaths is not the feelings they have or don’t have, it’s the choices they make.
Psychopaths commit an astonishing amount of crime, and this crime is both devastating to victims and astronomically costly to society as a whole.
And even though psychopaths are often portrayed as cold-blooded, almost alien predators, we have been showing that their emotional deficits may not actually be the primary driver of these bad choices.
Because it’s the choices of psychopaths that cause so much trouble, we’ve been trying to understand what goes on in their brains when the make decisions that involve trade-offs between the costs and benefits of action.
In this most recent paper…we are able to look at brain-based measures of reward and value and the communication between different brain regions that are involved in decision making.”
What the scans showed was that the brains of criminals were highly sensitive to rewards.
Dr Buckholtz said:
“So the more psychopathic a person is, the greater the magnitude of that striatal response.
That suggests that the way they are calculating the value rewards is dysregulated — they may over-represent the value of immediate reward.”
The ventral striatum is key in how we respond to rewards, Dr Buckholtz explained:
“We mapped the connections between the ventral striatum and other regions known to be involved in decision-making, specifically regions of the prefrontal cortex known to regulate striatal response.
When we did that, we found that connections between the striatum and the ventral medial prefrontal cortex were much weaker in people with psychopathy.”
What this means is that psychopaths don’t think very hard about the consequences of their actions: they are mostly focused on the rewards.
It turned out that the response in this area of the brain actually predicted the number of crimes the inmates had been convicted of.
Dr Buckholtz said:
“They’re not aliens, they’re people who make bad decisions.
The same kind of short-sighted, impulsive decision-making that we see in psychopathic individuals has also been noted in compulsive over-eaters and substance abusers.
If we can put this back into the domain of rigorous scientific analysis, we can see psychopaths aren’t inhuman, they’re exactly what you would expect from humans who have this particular kind of brain wiring dysfunction.”
The study was published in the journal Neuron (Buckholtz et al., 2017).