Repeated exposure and associative conditioning promote preschool children's liking of vegetables

Most young children do not meet current dietary recommendations, consuming too many energy-dense foods and too few nutrient-dense foods like vegetables. We compared two approaches to increasing children's liking of vegetables by having them repeatedly taste small portions of vegetables that were initially not liked, presented either alone (repeated exposure; RE) or with a liked dip (associative conditioning; AC). We first conducted a between-subjects experiment, where classrooms at a childcare center were each assigned a vegetable that most children did not like, and individual children were assigned to either the RE or AC condition. A second experiment was conducted to test whether the same results would be obtained using a within-subjects design, in which each child was assigned to repeatedly taste two vegetables that were not liked, one presented with dip and one without. In both experiments, vegetable liking was assessed before, during, and after a series of eight tasting trials, and vegetable intake was measured before and after the tasting trials in Experiment 1. In both experiments, children's vegetable liking increased from pre- to post-test, but there was no evidence of associative conditioning effects. Increases in vegetable liking, as well as intake, were similar across conditions. Although the addition of the liked dip did not augment overall effects on vegetable liking, there was some evidence that the liked dips could be used to encourage initial tasting of vegetables. In both experiments and both conditions, increases in liking were detected by the sixth exposure to the vegetable. Additional tasting trials did not produce additional increases in liking, but the increases in liking were sustained throughout the experiments. The current evidence suggests that administering few small tastes of vegetables that are initially not liked can have a lasting impact on preschool children's liking and intake of those vegetables. (C) 2011 Elsevier Ltd. All rights reserved.