Facial expressions in school-aged children are a good indicator of ‘dislikes’, but not of ‘likes’

Our pilot study sought to investigate whether facial expressions are a suitable and accurate method to assess food preferences in school-aged children. Six children, aged 5–13 years, tasted seven stimuli in randomized order: apple, sauerkraut, and beetroot juice, skimmed milk, asparagus solution, a bitter and a sweet solution. Their preferences were assessed using a traditional rank order procedure. Each tasting was video-recorded to capture facial expressions. The first six seconds after tasting were coded using a selection of FACS-system Action Units (AUs). Data were analysed by frequency count, Pearson correlations and Chi-Square test. For disliked liquids, the majority of the AUs displayed were negative, whereas for neutral and liked liquids the number of positive and negative AUs was similar. On the basis of our results, we conclude that facial expressions are suitable to measure dislike, but not suitable to measure various gradients of food acceptance in children aged 5–13 years.