Criminal Minds Are Different From Yours, Brain Scans Reveal

The latest neuroscience research is presenting intriguing evidence that the brains of certain kinds of criminals are different from those of the rest of the population.

While these findings could improve our understanding of criminal behavior, they also raise moral quandaries about whether and how society should use this knowledge to combat crime.

Brain scans

The criminal mind
In one recent study, scientists examined 21 people with antisocial personality disorder – a condition that characterizes many convicted criminals. Those with the disorder “typically have no regard for right and wrong. They may often violate the law and the rights of others,” according to the Mayo Clinic.

Brain scans of the antisocial people, compared with a control group of individuals without any mental disorders, showed on average an 18-percent reduction in the volume of the brain’s middle frontal gyrus, and a 9 percent reduction in the volume of the orbital frontal gyrus – two sections in the brain’s frontal lobe.

Another brain study, published in the September 2009 Archives of General Psychiatry, compared 27 psychopaths — people with severe antisocial personality disorder — to 32 non-psychopaths. In the psychopaths, the researchers observed deformations in another part of the brain called the amygdala, with the psychopaths showing a thinning of the outer layer of that region called the cortex and, on average, an 18-percent volume reduction in this part of brain.

“The amygdala is the seat of emotion. Psychopaths lack emotion. They lack empathy, remorse, guilt,” said research team member Adrian Raine, chair of the Department of Criminology at the University of Pennsylvania, at the annual meeting of the American Association for the Advancement of Science in Washington, D.C., last month.

University of Pennsylvania criminologist Adrian RainePin It University of Pennsylvania criminologist Adrian Raine
Credit: U PennView full size image
In addition to brain differences, people who end up being convicted for crimes often show behavioral differences compared with the rest of the population. One long-term study that Raine participated in followed 1,795 children born in two towns from ages 3 to 23. The study measured many aspects of these individuals’ growth and development, and found that 137 became criminal offenders.

One test on the participants at age 3 measured their response to fear – called fear conditioning – by associating a stimulus, such as a tone, with a punishment like an electric shock, and then measuring people’s involuntary physical responses through the skin upon hearing the tone.

In this case, the researchers found a distinct lack of fear conditioning in the 3-year-olds who would later become criminals. These findings were published in the January 2010 issue of the American Journal of Psychiatry.

Neurological base of crime

Overall, these studies and many more like them paint a picture of significant biological differences between people who commit serious crimes and people who do not. While not all people with antisocial personality disorder — or even all psychopaths — end up breaking the law, and not all criminals meet the criteria for these disorders, there is a marked correlation.

“There is a neuroscience basis in part to the cause of crime,” Raine said.

What’s more, as the study of 3-year-olds and other research have shown, many of these brain differences can be measured early on in life, long before a person might develop into actual psychopathic tendencies or commit a crime.

Criminologist Nathalie Fontaine of Indiana University studies the tendency toward being callous and unemotional (CU) in children between 7 and 12 years old. Children with these traits have been shown to have a higher risk of becoming psychopaths as adults.

“We’re not suggesting that some children are psychopaths, but CU traits can be used to identify a subgroup of children who are at risk,” Fontaine said.

Yet her research showed that these traits aren’t fixed, and can change in children as they grow. So if psychologists identify children with these risk factors early on, it may not be too late.

“We can still help them,” Fontaine said. “We can implement intervention to support and help children and their families, and we should.”

These brain scans of psychopaths show a deformation in the amygdala compared to non-psychopaths, from a study by Adrian Raine and colleagues.Pin It These brain scans of psychopaths show a deformation in the amygdala compared to non-psychopaths, from a study by Adrian Raine and colleagues.
Credit: Yang et al./Archives of General PsychiatryView full size image
Neuroscientists’ understanding of the plasticity, or flexibility, of the brain called neurogenesis supports the idea that many of these brain differences are not fixed. [10 Things You Didn’t Know About the Brain]

“Brain research is showing us that neurogenesis can occur even into adulthood,” said psychologist Patricia Brennan of Emory University in Atlanta. “Biology isn’t destiny. There are many, many places you can intervene along that developmental pathway to change what’s happening in these children.”

Furthermore, criminal behavior is certainly not a fixed behavior.

Psychologist Dustin Pardini of the University of Pittsburgh Medical Center found that about four out of five kids who are delinquents as children do not continue to offend in adulthood.

Pardini has been researching the potential brain differences between people with a past criminal record who have stopped committing crimes, and those who continue criminal behavior. While both groups showed brain differences compared with non-criminals in the study, Pardini and his colleagues uncovered few brain differences between chronic offenders and so-called remitting offenders.

“Both groups showed similar results,” Pardini said. “None of these brain regions distinguish chronic and remitting offenders.”

Ethical quandaries

Yet even the idea of intervening to help children at risk of becoming criminals is ethically fraught.

“Do we put children in compulsory treatment when we’ve uncovered the risk factors?” asked Raine. “Well, who decides that? Will the state mandate compulsory residential treatment?”

What if surgical treatment methods are advanced, and there is an option to operate on children or adults with these brain risk factors? Many experts are extremely hesitant to advocate such an invasive and risky brain intervention — especially in children and in individuals who have not yet committed any crime.

Yet psychologists say such solutions are not the only way to intervene.

“You don’t have to do direct brain surgery to change the way the brain functions,” Brennan said. “You can do social interventions to change that.”

Fontaine’s studies, for example, suggest that kids who display callous and unemotional traits don’t respond as well to traditional parenting and punishment methods such as time-outs. Instead of punishing bad behavior, programs that emphasize rewarding good behavior with positive reinforcement seem to work better.

Raine and his colleagues are also testing whether children who take supplemental pills of omega-3 fatty acids — also known as fish oil — can show improvement. Because this nutrient is thought to be used in cell growth, neuroscientists suspect it can help brain cells grow larger, increase the size of axons (the part of neurons that conducts electrical impulses), and regulate brain cell function.

“We are brain scanning children before and after treatment with omega-3,” Raine said. “We are studying kids to see if it can reduce aggressive behavior and improve impaired brain areas. It’s a biological treatment, but it’s a relatively benign treatment that most people would accept.”

‘Slippery slope to Armageddon’

The field of neurocriminology also raises other philosophical quandaries, such as the question of whether revealing the role of brain abnormalities in crime reduces a person’s responsibility for his or her own actions.

“Psychopaths know right and wrong cognitively, but don’t have a feeling for what’s right and wrong,” Raine said. “Did they ask to have an amygdala that wasn’t as well functioning as other individuals’? Should we be punishing psychopaths as harshly as we do?”

Because the brain of a psychopath is compromised, Raine said, one could argue that they don’t have full responsibility for their actions. That — in effect — it’s not their fault.

In fact, that reasoning has been argued in a court of law. Raine recounted a case he consulted on, of a man named Herbert Weinstein who had killed his wife. Brain scans subsequently revealed a large cyst in the frontal cortex of Weinstein’s brain, showing that his cognitive abilities were significantly compromised.

The scans were used to strike a plea bargain in which Weinstein’s sentence was reduced to only 11 years in prison.

“Imaging was used to reduce his culpability, to reduce his responsibility,” Raine said. “Yet is that not a slippery slope to Armageddon where there’s no responsibility in society?”

Psychopaths May Be Overrepresented In Big Business, Given Smarts And Manipulation Skills

The bible of psychiatric disorders, the fifth edition of the Diagnostic and Statistical Manual, known more colloquially as DSM-5, doesn’t include “psychopath” in any of its near-1,000 pages. It lists the collection of symptoms normally included in the moniker instead as “antisocial personality disorder.” And businesspeople may be more prone to having it.


Researchers from the University of Huddersfield recently conducted a study that found an ability to mask galvanic skin responses among high-IQ individuals could indicate the presence of antisocial personality disorder, referred to in the language of this particular research as psychopathy. It’s believed a combination of cunning smarts and a knack for social manipulation could help explain why psychopathic behavior is found more often in business than in the general population.

“I thought that intelligence could be an explanation for this, and it could be a problem if there are increased numbers of psychopaths at a high level in business,” said lead researcher and psychological scientist Carolyn Bate in astatement.

Bate’s research draws upon prior findings that showed out of 203 corporate professionals, roughly three percent scored high enough on two tests of psychopathic traits to qualify as embodying psychopathy — although no formal diagnoses were made. This three percent was the fuel for Bates’ study because it stands in contrast to the general population’s rate of only one percent. Why, she wanted to know, were business people three times more likely to embody this behavior?

Her team’s study recruited 50 people to answer the question. First, each person took a standard IQ test. Then they took a second test, called the Levenson Self-Report Psychopathy Scale, to assess whether they had either Factor One or Factor Two psychopathic tendencies. Factor One tendencies include boldness and extreme assertiveness. Factor Two tendencies include poor impulse control and exploitative tendencies.

The meat of the study came next: Bate hooked each participant up to a machine that read galvanic skin response (GSR). She showed them either neutral images or ones intended to shock the average person, and she recorded how people with each set of psychopathic tendencies reacted to the shocking images. Her hypothesis, that people with higher IQ scores and psychopathic tendencies were more likely not to register a GSR, was confirmed.

The upshot, she says, isn’t all that clear. The findings may point in one direction, namely that people with psychopathic tendencies are usually smarter, but whether businesses need to change their practices to accommodate the research is debatable. On the one hand, she concedes “this could have a detrimental effect on our everyday lives,” but she also acknowledges that business has been run the same way for many years; the necessary changes could be systemic.

“Perhaps businesses do need people who have the same characteristics as psychopaths, such as ruthlessness,” she said. “But I suspect that some form of screening does need to take place, mainly so businesses are aware of what sort of people they are hiring.”

In other words, of course businesses would rather higher bulldogs. But the net effect of high-ranking managers who would just as quickly step on someone’s throat to get where they’re going certainly seems like a negative outside the office. They might not actually kill anyone to get a promotion, but, to revert back to the language of the DSM, their antisocial tendencies may kill with kindness. Or at least what looks like kindness.

Source: Bate C, Boduszek D, Dhingra K, Bale C. Psychopathy, intelligence and emotional responding in a non-forensic sample: an experimental investigation.The Journal of Forensic Psychiatry & Psychology. 2014.

Science in the Courtroom.

Scientific evidence concerning the biological causes of bad behavior is becoming increasingly common in the courtroom. Forensic psychiatrists at Vanderbilt University have genetically screened defendants charged with first-degree murder for a gene associated with antisocial personality disorder, for example. And when it came time to sentence convicted murderer Brian Dugan, neuroscientists performed neuroimaging on Dugan’s brain in order to claim he has a defective, psychopathic brain.

What would you do if you were faced with such a decision? Imagine you’re a juror tasked with the job of recommending a sentence for a criminal found guilty of aggravated battery. The criminal, Jonathan Donahue, went into a Burger King restaurant with the hope of robbing it, then beat the manager so severely that he sustained brain damage. After he was arrested, Donahue seemed to revel in his crime, even going so far as to have a king’s crown tattooed on his back.

At the sentencing hearing, a psychiatrist provides expert testimony saying that Donahue is a diagnosed psychopath. She explains that psychopathy is a clinical diagnosis defined by impulsivity, lack of empathy, and lack of remorse. The judge tells you that the standard sentence for cases of aggravated battery is about 9 years.

First Question: With this information, how many years in prison will you recommend for Donahue?

There’s one more expert witness. This one is a neurobiologist, and he tells you that Donahue has a particular gene that contributes to atypical brain development. Specifically, the part of Donahue’s brain that controls his violence-inhibition mechanism is damaged. In normal humans, the violence-inhibition mechanism automatically creates anxiety when they recognize that other humans are in pain or distress. Psychopaths, like Donahue, lack a normal violence-inhibition mechanism.

Second Question: In light of this additional neurobiological evidence, how many years in prison will you recommend for Donahue?

How did you answer the Second Question relative to the First Question? If you increased Donahue’s sentence, you probably did so because you interpreted the neurobiological evidence as suggesting his biological constitution makes him a continued threat to society. On the other hand, if you decreased Donahue’s sentence, you probably did so because you interpreted the neurobiological evidence as suggesting his biological constitution makes him less responsible for his actions. Or, you could have dismissed the neurobiological evidence entirely and recommended the exact same sentence.

This is the double-edged sword of the science of criminal behavior. The exact same evidence could either increase or decrease punishment, depending on how that evidence is interpreted.

With scientific evidence about the causes of criminal behavior becoming more and more common in the court room, the legal system faces a pressing question: Which way will the double-edged sword cut? In Dugan’s murder case, a jury ultimately sentenced Dugan to death, but according to his attorney the scientific evidence switched a slam dunk case against Dugan into a much more complicated decision for the jurors. To investigate this question in a systematic way, my colleagues and I performed a national experiment involving US state trial court judges. We presented the judges with Donahue’s case and asked them to sentence him. The results of this experiment were published last month in Science. The judges told us that on average they sentenced convicts guilty of aggravated battery to about 9 years in prison. The judges who received only expert testimony concerning Donahue’s diagnosis of psychopathy sentenced him on average to almost 14 years in prison. But the judges who received the expert testimony concerning Donahue’s diagnosis of psychopathy as well as the evidence concerning the neurobiological causes of his psychopathy sentenced him on average to about 13 years in prison. Compared to just the diagnosis of psychopathy, that is, the neurobiological evidence reduced Donahue’s sentence by roughly a year (a statistically significant difference).

So, our study suggests which way the double-edged sword might cut—towards slightly shorter sentences. But there is another pressing question, one at the intersection of science, philosophy, and the law: Which way should the double-edged sword cut?

The presence of scientific evidence about the causes of criminal behavior is only likely to increase in the courtroom. As a result, scientists and non-scientists alike need to discuss this issue and decide how biological knowledge should influence the legal system.

To get the conversation going, in the Comments section below, list your answers to the First and Second Questions and explain your justification for the increase, decrease, or lack of any change in the prison sentence that you recommended for Donahue.

James Tabery is a professor of philosophy at the University of Utah.