Bluffers' brains built to baffle

How good are you at bluffing? A brain scan study released Monday suggests that liars' minds fire differently than less sneaky folks.

Over the last decade, a series of brain scan studies have suggested that people's brains fire differently when they are telling lies. The Proceedings of the National Academy of Sciences journal report led by Meghana Bhatt of Baylor College of Medicine in Houston advances those studies to look at how deception plays out over time in the brain.

"Wolves in sheep's clothing, the deceptive people acted like honest ones, until they could make a big score," Bhatt says. "And parts of the brain were much more active in strategically deceptive people while this was going on."

In the study, 76 volunteers played a "yard sale" game where "buyers" in each turn offer a price for a "widget" after being told its true value. The "sellers" replied with a sale price, and if it was less than the true value of the widget, the sale took place.

Only the buyers knew the true value of the item and they pocketed the difference between the true value and the sales price, creating an incentive to dupe sellers.

Over 60 turns, about 40% of the buyers were honest, always trying to buy a widget for a price close to its true value, about 40% were cheapskates, always offering a low price, and 20% were connivers, offering honest buying prices for low-value widgets, but low-balling sellers on the high-value ones, where they stood to make a killing on buying something valuable at a cheap price. "They acted to create honest reputations until they could find a big pay-off," Bhatt says.

In brain scans, the deceptive buyers saw significantly increased brain activity in three distinct parts of the brain, linked in past studies to strategic thinking.

"I bet I could get them some interesting test subjects from our law school," says Hank Greely head of the Center for Law and the Biosciences at Stanford. "It's intriguing, not a lie-detector, but a really interesting look at deceptive behavior in the brain."

For researchers, Bhatta says, the deceptive behavior looks most interesting for what it suggests about people's abilities to put themselves in someone else's shoes, even if only to fool them. "You have to understand other people's expectations, and these people were very good at that. And not everyone is," she says.

"This type of research may ultimately be relevant for better understanding neurological or psychiatric conditions that impact on social cognition such as autism or sociopathy", says Caltech psychologist John O'Doherty, by email."It is also important to note that our present understanding of these types of brain processes is still in a very early stage and we are still far away from the point where we could use this type of approach to tell whether a particular individual is being deceptive."

By Dan Vergano

(Image from PNAS, "Neural signatures of strategic types in a two-person bargaining game", by Meghana Bhatt, Terry Lohrenz, Colin Camerer, and P. Read Montague.)