Tuesday, August 21, 2007

fMRI - detecting “switchers” and “stickers”
Tuesday, August 21st, 2007
from: A Beautiful Math by Tom Siegfried (Joseph Henry Press, 2006)In one experiment described by Montague and Berns, people chose either A or B on a computer screen and then watched a bar on the screen to see whether their choice earned a reward. (The bar recorded accumulated reward “points” as the game progressed.) As the game went on, the computer adjusted the rewards, based on the player’s choices. At first, choosing A raised the bar more, but choosing A too often made B a better bet. When A’s payoffs dropped, some players noticed right away and quickly switched to choosing B more often. But others stuck with A, gambling that it would return to its previous high-payoff rate. It appeared that some brains are more inclined to take risks than others — some players play conservatively; others are risk-takers.
To me, it sounds more like they should be called “switchers” and “stickers”. But the labels don’t really matter. The most intriguiging result from this experiment is the revelations from the brain scans. Sure enough, patterns of brain activity differed in the two groups, particularly in a small clump of brain cells called the nucleus accembens. It’s a brain region implicated in drug addition, and it’s more active in the “risk-taking” game players (the stickers).
The neatest thing, though, is that you can tell who the risk takers and play-it-safers are from their brain scans just after the very beginning of the game, even while their behaviors are still identical.