Self-regulation and the embodiment of hunger

Abstract

Background: Self-regulation of health choices may result from activity in two interacting, processing systems. A ‘hot’, impulsive system can be contrasted with a more deliberative, ‘cold’ processing system. Lack of resources (e.g. being hungry) might make cold, deliberate decisions, and hence self-regulation, more difficult. We used the Ebbinghaus illusion that has been shown to influence conscious, deliberative estimates of size to test the effects of hunger on estimates of the calorie content of food. We predicted that only sated estimates would be influenced by the illusory figures. Methods: 115 students (40 fasted overnight, 40 sated, 35 sated follow up) estimated the amount of calories verbally in fake Japanese food presented on 16cm and 12.5cm plates on table cloths that induced the Ebbinghaus illusion. Analyses employed repeated measures ANCOVA. Findings: There was an interaction between the illusion contexts (small vs. big circles) and group, sated vs. fasted participants F(1, 74) = 5.47, p = .022. Only sated participants were influenced by the illusion such that calorie estimates were significantly higher when surrounded by small circles. Additionally, effects of plate size only occurred in the sated group. Discussion: The findings support our predictions that fasted participants are less likely to use deliberative processing. Estimates of calorie content when hungry were neither influenced by the illusion nor by plate size. While hungry individuals appear more ‘fool-proof’ in their estimates, any bias towards impulsive processing may impede attempts at self-regulation of calorie intake that may be important in many contexts.