Traffic light labels get the green light in German study

‘Traffic light’ nutrition labels are most effective in helping consumers’ self-control, German researchers have discovered. Using a brain scanner, a University of Bonn research team found that the labels were more effective in helping consumers resist high-calorie foods than purely information-based labels.

“This is the first study that analyses the effect that traffic light signals have on the evaluation processes in the consumer’s brain when making a purchase decision,” said Professor Doctor Bernd Weber of the Center for Economics and Neuroscience (CENs).

When shown products with a green traffic light label, study participants were willing to pay significantly more money for a product than when the same product bore an information-based label. However, if the label was ‘red’, the willingness to pay decreased more compared to the conventional information.

“You can conclude that the traffic light label acts as a reinforcer: the health relevance of the ingredients is weighed more heavily into purchasing decisions compared to simple nutrition information,” said Laura Enax, first author of a paper in the study that has been published in the journal Obesity.

Not only were participants inclined to pay less for a product with a red traffic light, but the red traffic light label also activated a structure in the left inferior frontal gyrus, which is important for self-control. Activity in this region influenced the ventromedial prefrontal cortex, a region that ‘calculates’ the subjective value of a product via the reward system, leading to a decreased willingness to pay for unhealthy products.

“The traffic light label appears to enable the study participants to better resist unhealthy foods compared to a label containing the traditional information on grams and percentages of the particular ingredients,” said Professor Weber.

“A traffic light label probably implicitly increases the weight consumers place on healthiness in their decision.”

The researchers now plan to examine more closely how different types of food labels can be used to support consumers in their decision-making.