Participants in the study, mostly UCLA students in their 20s, were given $30 and then asked whether they would agree to each of more than 250 gambles in which they had a 50-50 chance of winning an amount of money or losing another amount of money. Would they, for example, agree to a coin toss in which they could win $30 but lose $20? While the 16 participants were considering the possible wagers, they were in a functional magnetic resonance imaging (fMRI) scanner at UCLA's Ahmanson–Lovelace Brain Mapping Center, where researchers studied their brain activity; the technique uses magnetic fields to spot active brain areas by telltale increases in blood oxygen.
For each question, the participants answered whether they would strongly agree to the gamble, weakly accept it, weakly refuse it or strongly reject it. Participants were not told whether they had won or lost until after they left the scanner; afterwards, the researchers randomly selected three of the gambles, and if the participants had previously agreed to accept those, the researchers flipped a coin and the participants either won or lost the money. What interested the researchers, however, was the activity of the brain's regions during the decision-making process, not the subject's reaction to winning or losing.
On average, participants needed to be offered a 50 percent chance of winning about $19 to risk losing $10, but that amount varied widely among the subjec
Source:University of California - Los Angeles