Hedonic responses to foods are often measured using subjective liking ratings scales. This is problematic because food behaviours are complex and single measurements points that occur after tasting are unable to capture an individual’s dynamic affective state. To address this limitation, techniques have been developed to sample subjective affective responses during oral processing, such as temporal dominance of emotion. These methods are also limited because they interrupt natural behaviours associated with food and oral processing. The present research investigates the potential use of electromyography as a means to predict subjective liking ratings using affective facial muscle activity recorded at different phases of oral processing while tasting liquids. Using linear mixed models, muscle activity recorded while emptying into the mouth, swirling, and thinking about the taste of bitter and sweet liquid solutions was used to predict subjective liking ratings. During different phases of the tasting, these mixed models demonstrate that zygomaticus major activity predicted increased liking and that corrugator supercilii and levator labii superioris predicted decreased liking. The change in liking ratings predicted by each muscle varied depending on whether participants were emptying, swirling, or thinking about the taste. We conclude that facial muscle activity is a valuable measure of affective responses during dynamic food behaviours.
Muscle activity during oral processing of sticky-cohesive foods
