Investigation of eye tracking, electrodermal activity and facial expressions as biometric signatures of food reward and intake in normal weight adults

Abstract

Pervasive exposure to a vast and varied food repertoire has contributed to the obesity epidemic. Within this issue, there is a need for a better understanding of the psychophysiological responses to food cues that precede food choice and food intake to establish how these responses contribute to the link between food availability and increasing obesity levels. Biometric measures such as eye tracking, electrodermal activity and facial expressions may separately or collectively provide deeper insight into psychophysiological processes underlying food reward and food intake. We examined how biometric responses differed in foods varying in fat and taste and explored how these biometric signatures to food cues were related to food preference behaviours, food choice, and food intake. We developed and tested a biometric food preference task designed to concurrently assess biometric responses (eye tracking, electrodermal activity and facial expressions) and food reward to visual food stimuli from different food categories in 100 normal weight adults. Food intake and selection was examined using a simultaneous choice ad libitum buffet. The results from this cross-sectional study showed significant differences in visual attention towards foods varying in fat content and taste prior to making rapid food choice decisions. Furthermore, the study found positive associations between maintained attention during a forced choice paradigm and subsequent food reward and food intake measures. Attention, arousal and facial expression during passive viewing were not associated with food reward or intake measures, except for an association between negative valence and explicit liking such that less liked foods elicited stronger negative facial expressions. The findings indicate that implicit, biometric responses to food cues predict both food reward and actual food intake.