Suspicion resides in two regions of the brain

May 17, 2012
Read Montague, Ph.D., and colleagues at the Virginia Tech Carilion Research Institute discovered two distinct sites for suspicion in the brain: the amygdala, which correlates strongly with a baseline distrustfulness, and the parahippocampal gyrus, which acts like a cerebral lie detector. Credit: Virginia Tech

Fool me once, shame on you. Fool me twice, shame on my parahippocampal gyrus.

Scientists at the Virginia Tech Carilion Research Institute have found that suspicion resides in two distinct regions of the brain: the amygdala, which plays a central role in processing fear and , and the parahippocampal gyrus, which is associated with and the recognition of scenes.

"We wondered how individuals assess the credibility of other people in simple social interactions," said Read Montague, director of the Human Neuroimaging Laboratory and the Computational Psychiatry Unit at the Virginia Tech Carilion Research Institute, who led the study. "We found a strong correlation between the amygdala and a baseline level of distrust, which may be based on a person's beliefs about the trustworthiness of other people in general, his or her , and the situation at hand. What surprised us, though, is that when other people's behavior aroused suspicion, the parahippocampal gyrus lit up, acting like an inborn ."

The scientists used , or , to study the of suspicion. Seventy-six pairs of players, each with a buyer and a seller, competed in 60 rounds of a simple bargaining game while having their brains scanned. At the beginning of each round, the buyer would learn the value of a hypothetical widget and suggest a price to the seller. The seller would then set the price. If the seller's price fell below the widget's given value, the trade would go through, with the seller receiving the selling price and the buyer receiving any difference between the selling price and the actual value. If the seller's price exceeded the value, though, the trade would not execute, and neither party would receive cash.

The authors found, as detailed in a previous paper, that buyers fell into three strategic categories: 42 percent were incrementalists, who were relatively honest about the widget's value; 37 percent were conservatives, who adopted the strategy of withholding information; and 21 percent were strategists, who were actively deceptive, mimicking incrementalist behavior by sending high suggestions during low-value trials and then reaping greater benefits by sending low suggestions during high-value trials.

The sellers had a monetary incentive to read the buyers' strategic profiles correctly, yet they received no feedback about the accuracy of the information they were receiving, so they could not confirm any suspicions about patterns of behavior. Without feedback, the sellers were forced to decide whether they should trust the buyers based on the pricing suggestions alone. "The more uncertain a seller was about a buyer's credibility," Montague said, "the more active his or her parahippocampal gyrus became."

The authors believe a person's baseline suspicion may have important consequences for his or her financial success. "People with a high baseline suspicion were often interacting with fairly trustworthy buyers, so in ignoring the information those buyers provided, they were giving up potential profits," said Meghana Bhatt, the first author on the research paper. "The ability to recognize credible information in a competitive environment can be just as important as detecting untrustworthy behavior."

The findings may also have implications for such psychiatric conditions as paranoia and anxiety disorders, said Montague. "The fact that increased amygdala activation corresponds to an inability to detect trustworthy behavior may provide insight into the social interactions of people with anxiety disorders, who often have increased activity in this area of the brain," he said.

The research appeared in the early online edition of the Proceedings of the National Academy of Sciences (PNAS) on May 10 in the article "Distinct contributions of the and parahippocampal gyrus to suspicion in a repeated bargaining game" by Meghana Bhatt, PhD, an assistant research professor at the Beckman Research Institute of the City of Hope Hospital in Duarte, Calif.; Terry Lohrenz, PhD, a research assistant professor in the Virginia Tech Carilion Research Institute; Colin F. Camerer
, PhD, the Robert Kirby Professor of Behavioral Economics at the California Institute of Technology; and Montague, PhD, the corresponding author, who is a professor of physics at the Virginia Tech Carilion Research Institute and in the College of Science at Virginia Tech. The research was supported by grants to Read Montague from the Wellcome Trust and the National Institutes of Health.

Explore further: Group settings can diminish expressions of intelligence, especially among women

Related Stories

Group settings can diminish expressions of intelligence, especially among women

January 22, 2012
In the classic film "12 Angry Men," Henry Fonda's character sways a jury with his quiet, persistent intelligence. But would he have succeeded if he had allowed himself to fall sway to the social dynamics of that jury?

Expertise provides buffer against bias in making judgments

June 6, 2011
Gratuities, gifts, sponsorship, product price, free samples, favors all can influence judgment and decision-making. If a person is influenced in their choice of cereal, the result is a bit of income for a manufacturer. But ...

Brain imaging, behavior research reveals physicians learn more by paying attention to failure

November 23, 2011
When seeking a physician, you should look for one with experience. Right? Maybe not. Research on physicians' decision-making processes has revealed that those who pay attention to failures as well as successes become more ...

Functional MRI shows how mindfulness meditation changes decision-making process

April 20, 2011
If a friend or relative won $100 and then offered you a few dollars, would you accept this windfall? The logical answer would seem to be, sure, why not? "But human decision making does not always appear rational," said Read ...

Dopamine release in human brain tracked at microsecond timescale reveals decision-making

October 28, 2011
A research team led by investigators at the Virginia Tech Carilion Research Institute has demonstrated the first rapid measurements of dopamine release in a human brain and provided preliminary evidence that the neurotransmitter ...

Recommended for you

Brain stimulation may improve cognitive performance in people with schizophrenia

July 24, 2017
Brain stimulation could be used to treat cognitive deficits frequently associated with schizophrenia, according to a new study from King's College London.

New map may lead to drug development for complex brain disorders, researcher says

July 24, 2017
Just as parents are not the root of all their children's problems, a single gene mutation can't be blamed for complex brain disorders like autism, according to a Keck School of Medicine of USC neuroscientist.

Bird songs provide insight into how developing brain forms memories

July 24, 2017
Researchers at the University of Chicago have demonstrated, for the first time, that a key protein complex in the brain is linked to the ability of young animals to learn behavioral patterns from adults.

Working around spinal injuries: Rehabilitation, drug treatment lets rats recover some involuntary movement

July 24, 2017
A new study in rats shows that changes in the brain after spinal cord injury are necessary to restore at least some function to lower limbs. The work was published recently in the journal eLife.

Scientists capture first image of major brain receptor in action

July 24, 2017
Columbia University Medical Center (CUMC) researchers have captured the first three-dimensional snapshots of the AMPA-subtype glutamate receptor in action. The receptor, which regulates most electrical signaling in the brain, ...

Research identifies new brain death pathway in Alzheimer's disease

July 24, 2017
Alzheimer's disease tragically ravages the brains, memories and ultimately, personalities of its victims. Now affecting 5 million Americans, Alzheimer's disease is the sixth leading cause of death in the U.S., and a cure ...

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Tausch
not rated yet May 18, 2012
"We wondered how individuals assess the credibility of other people in simple social interactions," said Read Montague, director of the Human Neuroimaging Laboratory and the Computational Psychiatry Unit at the Virginia Tech Carilion Research Institute, who led the study


*Sigh*
How many words must you write?*
*To admit you know little about sources of "simple social interactions"

Revoke all your learning degrees. Find mentors that guide your curiosity to questions that lend at least plausibilty to your conjecture and/or models.
HealingMindN
not rated yet May 18, 2012
But they get paid by the word. How can they justify their existence w/o all that wordiness? Oh wait. My high pressure emotional valve is about to let off some steam! Oh shoot! I don't know who to trust now...

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.