Salient nutrition labels shift peoples' attention to healthy foods and exert more influence on their choices

Abstract

Nutrition labels are the most commonly used tools to promote healthy choices. Research has shown that color-coded traffic light (TL) labels are more effective than purely numerical Guideline Daily Amount (GDA) labels at promoting healthy eating. While these effects of TL labels on food choice are hypothesized to rely on attention, how this occurs remains unknown. Based on previous eye-tracking research we hypothesized that TL labels compared to GDA labels will attract more attention, will induce shifts in attention allocation to healthy food items, and will increase the influence of attention to the labels on food choice. To test our hypotheses, we conducted an eye-tracking experiment where participants chose between healthy and unhealthy food items accompanied either by TL or GDA labels. We found that TL labels biased choices towards healthier items because their presence caused participants to allocate more attention to healthy items and less to unhealthy items. Moreover, our data indicated that TL labels were more likely to be looked at, and had a larger effect on choice, despite attracting less dwell time. These results reveal that TL labels increase healthy food choice, relative to GDA labels, by shifting attention and the effects of attention on choice.

Introduction

In a world with high rates of obesity accompanied by tremendous consequences and costs, understanding the mechanisms underlying food choice is crucial [1,2]. Deciding if, what, when, and how much to eat involves an interplay between the internal homeostatic balance and cognitive capacity–which encapsulates the ability to behave in line with one's goals [2,3]. Even though being healthy and living healthy seem like straightforward goals to have, research shows that the ability to behave in line with these goals seems to depend not only on interindividual differences in decision-making processes, but also on external cues that may promote different goals [[4], [5], [6], [7]]. Among these external cues are nutrition labels which have become the most commonly used tool to promote healthy food choices [8].

While overall the presence of nutrition labels seems to have an impact on food choices, not all label formats are equally effective. Several studies have shown that compared to numerical labels (eg, monochrome Guideline of Daily Amount–GDA), labels that provide nutrition information in a more salient and easy to interpret way are more effective in helping consumers identify and choose healthier foods [[9], [10], [11], [12], [13], [14], [15], [16], [17], [18]]. One type of salient label, which uses color codes to indicate nutrient levels, is the traffic light (TL) label. These labels have been shown to be effective in promoting healthy choice [18] but the exact mechanisms underlying their effects remain unknown.

Many studies have shown that when attended to, TL labels increase health awareness [19,20], which is an important factor associated with healthy food choice [2,5]. In line with this, Enax et al [21] showed that TL labels increase the weight on health attributes in the decision-making process. These effects of salient nutrition labels on food choice have been hypothesized to rely on attention [7,21]. Supporting this idea, eye-tracking research has shown that while front-of-package labels attract visual attention [22], some formats attract more attention than others. More specifically, it has been shown that color coded labels, like TL labels, attract more attention than monochromatic, numerical labels [12,14,22]. Interestingly, these effects have been reported even in more naturalistic shopping environments such as canteens, where participants can see different food items with different label formats on their packaging [23]. However, what these studies do not answer is how attention more specifically relates to subsequent food choice [12,23,24].

In recent years, research has shown that attention plays an important role in the choice process, amplifying the value of attended items and attributes, and so increasing their impact on choice outcomes (for a review see [25]). These studies provide a framework for understanding how salient nutrition labels might encourage healthy food choice. The first possibility is that more salient labels simply attract more gaze, leading to more weight on nutritional information in participants' choices. A second possibility is that more salient labels divert attention away from unhealthy items towards healthy items, giving healthy items an advantage in the comparison process. Finally, a third possibility is that more salient labels more effectively convey nutrition information, thereby increasing the influence of attention paid to the label on the food choice.

The aim of this study is to explore these possibilities by examining the relationship between visual attention and food choice in the presence of different nutrition labels. Based on the findings from previous eye-tracking studies [12,25], we hypothesized that: (H1) more salient labels will attract more attention and will increase the weight of health in the decision process; (H2) more salient labels will increase the proportion of time that participants dwell on the healthier item; (H3) more salient labels will increase the correlation between attention and food choice. To test these hypotheses, we conducted an eye-tracking experiment where we assessed visual attention while participants performed a binary food choice task between healthy and unhealthy food items in either the presence of purely numerical labels (GDA labels) or in the presence of color-coded and thus more salient labels (TL labels).