The study, published this week in the Journal of Neuroscience, used fMRI brain imaging and pictures depicting food, erotica, landscapes, and people to gauge how the test subjects' accumbens reacted to each stimulus. (The 48 women who completed the study had no idea what it was actually about.)
Six months later, the women returned to the lab where they were weighed and asked to fill out a questionnaire. Those whose accumbens reacted especially strongly to food cues had gained more weight. And those who reacted to sexual cues most strongly were more likely to have had sex and report stronger sexual desire.
Interestingly, their "appetites" did not cross over. The women with hyperactive responses to sex cues did not have a hyperactive response to food and vice versa.
Bill Kelley, associate professor of Dartmouth's department of psychological and brain sciences, says the study shows that the activation of one brain region proved to be a strong predictor of later behavior, demonstrating that the stronger the “liking” response to a stimulus, the less able we are to “hear” our rational brain saying “no.”
But are we born this way, or do we acquire stronger craving for specific rewards?
“That’s a great question,” said Kathryn Demos, who led the study and is now an assistant professor of psychiatry and human behavior at Brown University.
Kelley thinks that since different women were tempted by different things, their brain wiring has developed through experience, aided by a genetic component.
Luckily, there are tools that can help people blunt the power of their brain wiring. Behavioral therapies, for example, have had some limited success in people who seem strongly stimulated by food.
People can also try to replace various cravings with something more healthful, for instance, going for a run whenever they're tempted to eat a cheeseburger.
As for the findings, Demos says the idea that all people are equally capable of self-control is naïve.
Reward, she says, “is a very powerful system.”