Wetenschap - 1 mei 2013

Brain scans show how willpower works

Paul Smeets looks deep into students' brains.
Dieting students resist food better.


Foto: .

What happens when dieting women look at appetizing pictures of food? Wageningen researcher Paul Smeets (Nutrition chair group) and colleagues from the University of Utrecht scanned students' brains in order to find out. Working at the Image Sciences Institute, the researchers compared the response to food with that to office equipment. The differences in response were then correlated with how much value the women placed on a trim figure.
The result is interesting. The more important their figure was to the women, the stronger their response to the sight of appetizing food. Women to whom it is more important to be slim apparently respond more alertly to dangerously delicious food than others. According to Smeets, that means that the alarm bells sound earlier for these women. The scans also show that parts of the brain that are related to self control respond more actively in dieting women.
Smeets and his colleagues see themselves as having provided neural support for a major psychological theory. Smeets: 'The standard theory is that a small temptation is easy to resist and a bigger one is not. An alternative view is the counteractive control theory which says the bigger the temptation, the sooner the brakes are activated. A strong temptation results in smart behavior. A weaker temptation does not set the alarm bells ringing.'
Postponed reward
Women who diet successfully are better at resisting chocolate cake, says Smeets. 'The brain scans show that when a conflict is registered between appealing food and the dieting goal, areas of the brain for self-control are activated.' In a sense, the scans show how willpower works. The more important it is to women to be slim, the louder the alarm bells ring when they see tempting food. 'In fact it is a question of whether you can wait for a distant reward, staying slim, or you succumb to an immediate reward, the cake.'