Sunday, March 28, 2010

Study: Psychopaths' Brains Wired To Seek Rewards

Scientists have long known what psychopaths lack: emotions like empathy, fear and remorse. Now, a new study focuses on what they may have, a brain abnormality that may lead them to seek rewards like money, sex or fame at any cost.
Vanderbilt graduate student Josh Buckholtz tells NPR's Guy Raz that psychopaths have a hyperactive reward system in their brains — the same reward system that drives drug addicts to seek another dose. But first, what exactly is a psychopath?
"We can think of psychopathy as a personality disorder," Buckholtz says. "It's a collection of related traits." Psychopaths are considered superficial, lacking fear, regret or empathy, he says, plus they also exhibit profoundly deviant social behavior.
"What prior research has shown is that psychopaths have changes in their brain … that are involved in generating emotional experiences," he continues. "We think that these changes in the brain's reward system might promote a focus on rewar—-- on obtaining a reward."
Buckholtz and team used brain scans to monitor the levels of dopamine — a chemical related to motivation and pleasure — in volunteers' brains during a variety of tests. He found that subjects who'd scored higher in psychopathic traits had correspondingly higher levels of dopamine and greater activity in areas of the brain related to seeking and enjoying rewards.
The correlation might account for the antisocial and aggressive behavior seen in psychopaths. Psychopaths may be so intent on the reward that other concerns — like causing harm or the possibility of punishment — fall by the wayside.
The study used community volunteers who took a test that measured psychopathic traits. "The people in our study might be your Machiavellian mother-in-law, your bullying boss and your conniving coworker, but none of these people were out there committing violent crimes," Buckholtz says. The results, however, still have relevance for diagnosed psychopaths. Turns out, there may be a little psychopath in all of us.
"Currently, it's thought that psychopathic traits operate along a continuum," Buckholtz says. That means you can measure a range of psychopathic traits in volunteers with no diagnosable psychiatric disorders.
And Buckholtz says that's important, because targeting and treating psychopathic behavior can help reduce crime. "Crime is extremely expensive," he says, "and psychopaths commit more crime than anybody else." And unfortunately, scientists know very little about how to treat psychopathy.
"This might lead the way for future studies that target this system as a way of reducing aggression and antisocial behavior," he says.

How the brain constructs morality

WASHINGTON: Our ability to respond appropriately to intended harms - that is, with outrage toward the perpetrator - is seated in a brain region associated with regulating emotions, says a new study.

According to MIT neuroscientists, patients with damage to this brain area, known as the ventromedial prefrontal cortex (VMPC), are unable to conjure a normal emotional response to hypothetical situations in which a person tries, but fails, to kill another person. Therefore, they judge the situation based only on the outcome, and do not hold the attempted murderer morally responsible.

The finding offers a new piece to the puzzle of how the human brain constructs morality, says Liane Young, a postdoctoral associate in MIT's Department of Brain and Cognitive Sciences and lead author of a paper describing the findings in the March 25 issue of the journal Neuron.

"We're slowly chipping away at the structure of morality," says Young. "We're not the first to show that emotions matter for morality, but this is a more precise look at how emotions matter."

Working with researchers at the University of Southern California, led by Antonio Damasio, Young studied a group of nine patients with damage (caused by aneurisms or tumors) to the VMPC, a plum-sized area located behind and above the eyes.

Such patients have difficulty processing social emotions such as empathy or embarrassment, but "they have a perfectly intact capacity for reasoning and other cognitive functions," says Young.

The researchers gave the subjects a series of 24 hypothetical scenarios and asked for their reactions. The scenarios of most interest to the researchers were ones featuring a mismatch between the person's intention and the outcome - either failed attempts to harm or accidental harms.

When confronted with failed attempts to harm, the patients had no problems understanding the perpetrator's intentions, but they failed to hold them morally responsible. The patients even judged attempted harms as more permissible than accidental harms (such as accidentally poisoning someone) - a reversal of the pattern seen in normal adults.

"They can process what people are thinking and their intentions, but they just don't respond emotionally to that information," says Young. "They can read about a murder attempt and judge it as morally permissible because no harm was done."

This supports the idea that making moral judgments requires at least two processes - a logical assessment of the intention, and an emotional reaction to it. The study also supports the theory that the emotional component is seated in the VMPC.