Towards an understanding of the role of facial expressions in the modelling of eating behaviour

Abstract

Facial expressions (FEs) can convey our enjoyment of food. Research has shown that exposure to others’ FEs towards food influences children and adults’ desire to eat food. However, the effect of adults’ FEs whilst eating on children’s and young adults’ consumption of nutritious foods that are less preferred (e.g., vegetables) remains to be established. Hence, the primary aim of this thesis was to investigate this effect. Results indicated that exposure to adults eating a vegetable with negative FEs reduced young adults’ liking of that vegetable, but not their desire to consume it. The effect of positive FEs was not consistent across populations, with Chapters 2 and 3 showing there was no effect on young adults’ desire to eat vegetables, and Chapters 4-6 indicating that exposure to positive FEs increased children’s consumption of the modelled vegetable. Chapter 4 showed an immediate positive effect of a single exposure to others’ enjoying a vegetable on children’s vegetable consumption, but Chapter 6 demonstrated that children required repeated exposure over one-week for the effect to be significant. Whilst exposure to others’ positive FEs increases vegetable intake for most children, Chapter 5 indicated that positive FEs were not effective for children with high food neophobia. Consistently across populations (Chapters 2, 3 & 6), there was no generalised effect of others’ FEs to a modelled vegetable on individuals’ eating of a non-modelled vegetable, suggesting that enjoyment of each food must be observed for increasing consumption. This thesis shows the effectiveness of children observing others’ food enjoyment to promote vegetable consumption, and the power of exposure to food disliking, for reducing vegetable liking. This highlights the importance of observational learning and food enjoyment in guiding eating behaviour. Further research is needed to determine the long-term effectiveness of using positive FEs to increase children’s vegetable consumption.