OBSERVATIONAL CONDITIONING OF FOOD VALENCE IN HUMANS

It has been suggested that the observation of a model consuming a food (CS) and facially expressing either to like or to dislike (US') the f ood, may be a sufficient condition to bring about a change in the vale nce of the food for the observer. Unfortunately, up to now this hypoth esis has not been investigated in a straightforward manner. In this st udy, during acquisition, children consumed a series of evaluatively ne utral colored and flavored drinks, while simultaneously they watched a videotaped model synchronically drinking identical drinks and faciall y expressing his evaluation (neutral or dislike) of the liquids. In on e condition, the presence of a particular flavor in the drinks was des ignated to function as the CS+ or the CS-, whereas in the other condit ion it was the color of the drinks which was the critical CS+ or CS-. Next, the children evaluated a series of drinks containing the critica l CSs. A clear evaluative learning effect was obtained when the flavor but not when the color of the drinks was systematically paired with t he model's facial expression of dislike. Moreover, the flavor conditio ning effect was dependent on the presence in the test drinks of the lo cal context cues (c.q. the colors of the drinks) which were used durin g acquisition. Finally a double dissociation was observed between expl icit beliefs and the ''evaluative knowledge'' expressed in the ratings of the drinks, in that none of the children in the CS=Flavor groups e videnced any explicit knowledge about the crucial CS-US' contingency b ut showed evaluative conditioning, whereas the majority of the childre n in CS=Color groups were aware of the CS-US' relation but failed to d emonstrate an evaluative CS+/CS- differentiation. (C) 1996 Academic Pr ess Limited