By studying how poker players bluff, scientists say they've uncovered new information on a brain region that may drive human decision-making in social settings.
Duke University researchers hooked 20 people to scanners and watched the brain's reaction as they played a one-card version of poker against either another person, or a computer.
The study, reported today in the journal Science, found the brain's temporal parietal junction was more reactive when the player faced a human opponent, and that activity in the region predicted whether the subject would bluff. This suggests that part of the brain may help coordinate our relationships with other people, said study author Scott Huettel.
"When you engage with another person and detect they're relevant for your behavior, this is the region that detects it," said Huettel, a professor of psychology and neuroscience at the Durham, North Carolina, university.
The research used a variety of poker simplified down to one card. The card was either high, and would win if the participant chose to bet, or low, indicating a loss if the research subject bet and was called. Participants won money with a high card or by bluffing with the low card.
Participants in the trial bluffed 54 percent of the time on average, according to the study, which was funded by the National Institutes of Health in Bethesda, Maryland.
The 20 subjects had their brains scanned with fMRI, or functional magnetic resonance imaging, a system used in hospitals that traces blood flow to produce detailed pictures of brain activity.
The findings "identify a unique and independent role" for the temporal parietal junction "in representing information predictable of behavioral actions during social interactions," according to the study.
The TPJ region was most active when a player faced a person whose actions could be modeled, and thus relevant for guiding future decisions, as opposed to a computer's more random response, the researchers wrote.
The difference in how the region reacted when the players faced another person rather than a computer showed a "unique sensitivity of this region to perceived behavioral relevance of other agents," according to the report.