Children's and adults' understanding of the impact of nutrition on biological and psychological processes.

Four studies examined children's and adults' beliefs about the impact of nutrition on growth and mood states. In Studies 1 and 2, 271 participants (preschoolers through adults) judged the impact of healthy and unhealthy nutrition on height and weight. In Studies 3 and 4, 267 participants judged the impact of healthy and unhealthy nutrition on positive and negative mood states. The results suggest that young children demonstrate a co-existence of an ontologically distinct theory of biology as well as a theory of cross-domain interaction when reasoning about the impact of food on biological and psychological processes.