The brain scan that could reveal a cold-blooded killer: Scientists discover key

Scientists have uncovered the brain structure that could reveal whether someone is a cold-blooded killer.

Researchers scanned the brains of 37 murderers while they were awaiting trial, and found that they all had a critical difference in a part of the brain called the amygdala.

This small structure is located deep within the brain, and plays a vital role in processing emotions, recognising fear, and making moral decisions.

But in the brains of confirmed killers, this vital structure was almost six per cent smaller than in the general population.

Even more strikingly, scientists believe that these brain scans can reveal the difference between cold-blooded murderers and those who kill in the moment.

The scientists reviewed the murderers’ case files and family reports to rate the degree of planning involved in the crime.

They discovered that the killers who premeditated their crimes had an even smaller amygdala, showing a 14.3 per cent reduction in volume.

Lead author Professor Adrian Raine, of the University of Pennsylvania, told the Daily Mail: ‘It’s the more “cold-blooded” murderers who have blunted emotions as indicated by this impairment in the amygdala; an impairment that can contribute to a lack of concern for others.’

Scientists have uncovered that changes to a brain structure called the amygdala could reveal whether someone is a cold-blooded killer (pictured). Killers had severe deformations (right) in parts of this region compared with normal people 

This is not the first study to look for differences in the brain structures of killers, but it is different in an extremely important way.

Previous studies have scanned the brains of criminals who have already been convicted and spent years in prison.

That time in such an intense, stressful environment can cause structural changes in the brain that would hide any predispositions towards violence.

Professor Raine’s study, however, looked at the brains of suspected murderers in China who were undergoing forensic psychiatric evaluation.

All the participants in the trial would go on to be found guilty, but they had committed their crimes just weeks or months ago and had not yet experienced any time in prison.

This gave researchers the best chance of isolating any specific differences in their brains that might have made them more likely to kill.

Using a structural magnetic resonance imaging scan (MRI), scientists pieced together a detailed image of the killer’s brain structure, and carefully traced the boundaries of the amygdala to work out its volume.

These scans showed that the amygdala was not only smaller, but that this shrinking was located in areas essential for learning from fear and avoiding painful outcomes.

Scientists found that the murderers had a significantly smaller amygdala than the non-criminal population, potentially resulting in blunted emotions 

Studies have shown that underdevelopment in these key zones is often linked to aggressive or disruptive behaviour in children and adults.

Alongside a reduction in the size of the amygdala, the researchers also found that murderers tended to have a smaller ‘lateral orbitofrontal cortex’.

Professor Raine says: ‘Interestingly, other studies have shown that healthy controls show increased activation of this brain area when they accidentally kill an innocent victim in a video game, giving them a sense of guilt for their wrongful action.

‘But if this brain area that gives rise to that sense of guilt is diminished, as it is in murderers, then that can take the brake off killing someone.’

In the study, published in the journal Aggression and Violent Behavior, psychiatrists also evaluated the participants to measure their personality traits.

They discovered that murder suspects who had a smaller amygdala scored higher for psychopathic traits.

This was most pronounced in the ‘affective’ features of psychopathy, including emotional shallowness and a lack of remorse.

Even among the non-criminal control population, people with smaller amygdalae had higher levels of affective psychopathic traits.

The amygdala plays a vital role in processing emotions, recognising fear, and making moral decisions. Without these responses, cold-blooded killers such as Ted Bundy (pictured) might have less preventing them from killing 

Pre-meditated killers had even smaller amygdala than those who killed impulsively, with a 14.3 per cent reduction in volume

Scientists believe that these brain differences cause the psychopathic traits that, in turn, make someone more likely to commit a premeditated murder.

While the researchers insist that these are ‘only one of a number of factors that predispose to violence’, they still act as a ‘predisposition’ towards violent crime.

Professor Raine says: ‘Brain scans can help reveal abnormalities that are associated with an increase in the likelihood of committing crime, but prediction is not perfect.

‘Some murderers have completely normal brain scans, and some normal people have abnormal brain scans.

‘But in combination with social, psychological, and health factors and the use of artificial intelligence and machine learning, prediction is likely to be improved in the future.’

WOULD YOU KNOW HOW TO SPOT A PSYCHOPATH?

Psychopaths display different traits depending on their disorder.

Common signs include superficial charm, a grandiose notion of self-worth, the need for stimulation and impulsiveness, pathological lying, the ability to manipulate others and a lack of remorse and empathy.

But despite the popular association, not all psychopaths become killers.

Experts claim people usually find psychopaths intriguing, but can’t put their finger on why. 

This is down to incongruous behaviour because psychopaths tend to do a lot of acting to deceive, or mimic normal reactions, sometimes changing their views and reactions quickly.

For example, Self-professed psychopath Jacob Wells said that upon meeting someone, he tries to become ‘the most interesting person they know’ and presumably adopts suitable interests and responses to do this.

His response also gives away another common trait – a grandiose notion of self-worth – in that he can be the most interesting person in the room.

Psychopaths occasionally tend to exhibit unconvincing emotional responses, with slip-ups including tone of voice or body language.

This may be because they are unable to understand emotions such as fear and love, but can mimic them.

Psychopaths display different traits depending on their disorder, but common signs include superficial charm and the ability to manipulate others. Despite the popular association, not all psychopaths become killers (stock image)

Generally psychopaths’ ’emotions’ are shallow and short-lived and there is a manipulative ulterior motive to showing them.

For example, Mr Wells said he offers to do favours and tells false secrets to people to gain their complete trust.

He also displays insincere charm – another trait associated with psychopaths.

He says: ‘I keep secrets, and tell them fake secrets to further gain their trust, and once they trust me enough, I ask for favours, reminding them of the favours I did them. I can get literally anything from them, which is incredibly useful.’

Psychopaths typically display an incredible ability to manipulate others and sometimes take pleasure in doing so. 

Psychopaths often have an air of superiority about them, perhaps shown by Mr Wells’ belief he can spot other psychopaths

Even expert Dr Hare, who came up with the Hare Psychopathy Checklist-Revised (PCL-R) used as a diagnostic tool to determine where someone lies on the psychopathy spectrum, warns that anyone can be duped during a short interaction with a psychopath.