Smeets, P. M., & Barnes-Holmes, D. (2003). Children's emergent preferences for soft drinks: Stimulus-equivalence and transfer. Journal of Economic Psychology, 24, 603-618.
Two experiments were conducted, each with 16 5-year-old children. In Experiment 1, the children were trained on two sets of match-to-sample tasks: B1-A1, B2-A2 and C1-B1, C2-B2, or A1-B1, A2-B2 and B1-C1, B2-C2. Stimuli A1 and A2 were the pictures of a smiling cartoon character and of a crying child, respectively. The B and C stimuli were arbitrarily selected geometric shapes and symbols, respectively. After having learned both tasks, the children were tested for equivalence responding (e.g., C1-A1, C2-A2). Finally, the subjects were presented with two samples of a same soft drink, one with label C1 and one with label C2. The subjects were asked to indicate which drink they would like to taste first. After having tasted both drinks, they were required to indicate which drink they preferred. Finally, they were asked which picture they liked most, A1 or A2. Experiment 2 was the same but without the equivalence test. Across both experiments, 29/32 children (91%) first wanted to taste the drink with the label (C1 or C2) that was indirectly related to the preferred picture (A1 or A2). After tasting both drinks, 26 of these children (90%) indicated that they also preferred that drink. These findings are consistent with and extend previous research on emergent preferences in adults.