The papers, both to be published in the American Marketing Association’s Journal of Public Policy & Marketing, both suggest researchers need to take particular care over how studies around consumer decision-making are constructed.
Lights and numbers
Researchers from Carnegie Mellon University looked at the efficacy of both traffic light labels – showing red, amber or green to indicate the relative calorie levels of food – and raw numerical nutrition information. To test this, they set up an online ordering system for employees at a large company, where participants could order lunch – with both interventions resulting in approximately a 10% reduction in calories consumed.
“The similar effect of traffic light and numeric labelling suggests that labels may merely facilitate comparisons between menu items, enabling consumers to select relatively healthier items at the point of purchase without leading to retention, or possibly registry in the first place, of verbatim knowledge about the items’ calorie content,” wrote the study’s authors.
The authors did note that other studies, in less controlled environments, suggested labelling of any kind may not be as effective as their study suggests – and observed some consumers may not understand numerical information as easily as they might the traffic light signals. But they also suggested advanced online shopping platforms such as Amazon may point towards new ways to positively influence consumers’ decisions.
“Researchers may want to contemplate ways to ‘supercharge’ such labelling and achieve additional calorie reductions, perhaps extending the effects beyond item substitution. With technological advancements improving the speed and availability of user feedback and information provision, static nutrition labels can be compared to more dynamic approaches, particularly for decisions made in the online context,” they wrote.
Another study, by researchers at the universities of Vanderbilt, Texas A&M and Rice, examined differences in people’s general self-control and their eating self-control, and how this can influence their decision-making. The researchers set up a number of different experiments, including detailed surveys and consumption tests, including one testing the effectiveness of different interventions around food.
The Snickers test
One experiment, in the form of a smartphone app, asked participants to think about eating a Snickers chocolate bar, then presented them with either numerical nutrition information, or a picture of a person’s feet walking, and a message reading “you must walk 65 minutes to burn off that Snickers bar” – and finally asked how likely they were to eat the bar.
The results suggested that participants with higher general self-control, and those shown the exercise message, were less likely to consume the bar.
“These findings show that the differences in effectiveness were particularly prominent for those low in eating self-control… suggesting that this naturally vulnerable type of consumer responded much more favourably to the exercise equivalency than the nutrition information,” wrote the study’s authors.
“The results support our hypotheses that the individual’s level of self-control not only affects significant outcomes (in this case, self-restraint in eating), but also affects the efficacy of interventions to promote such behaviours,” they added.
Overall, the researchers recommend so-called “domain-specific” methods and measurements to assess self-control, rather than relying on a measurement of general self-control. While there was a strong correlation between those with spending self-control and eating self-control, of around +0.50, the study showed 38.5% of people scored highly on one type, but poorly on the other.
Because of this, the study’s authors warned against linking food choices to financial choices: “From a public policy perspective, recommending interventions that help people improve their health and eat judiciously but simultaneously shift negative outcomes to the financial domain could be a real risk.”
Source: Journal of Public Policy & Marketing
“Calorie Label Formats: Using Numbers or Traffic Lights to Reduce Lunch Calories”
Published online ahead of print, doi:10.1509/jppm.14.149
Authors: E. M. VanEpps, J. S. Downs, G. Loewenstein
“Control Over What? Individual Differences in General versus Eating and Spending Self-Control”
Published online ahead of print, doi:10.1509/jppm.14.112
Authors: K. L. Haws, S. W. Davis, U. M. Dholakia