Differences in hedonic perception of retronasal odors between young children and adults.

Early childhood is a critical developmental period for the establishment of flavor preferences that in turn affect food and beverage consumption and health into adulthood. Flavor is a multisensory experience, combining taste and retronasal odor signals. However, while early life development of taste perception has received ample attention, there is limited knowledge of retronasal odor perception in early life. In the present cross-sectional study, we tested the hypothesis that hedonic perception of retronasal smell differs between children and adults. We used video analysis of facial expressions to taste and retronasal odor solutions in children and adults. Children ages 3-6 and one of their parents (n=112 dyads) were asked to sample solutions containing either a taste or an odor compound. A subset of subjects (n=84 dyads) also explicitly rated each solution on a pictorial liking scale. No differences between the two age groups were observed in responses to taste solutions. In contrast, responses to retronasal odor stimuli were less stimulus-specific in children compared to adults. Children showed fewer negative facial expressions to broccoli and pumpkin odors, and more negative facial expressions to apple and mango odors. Similar differences between the two age groups were observed in explicit hedonic ratings. These findings support our hypothesis that the hedonic value of retronasal odor components of flavor are not innate but differ between young children and adults.