Acquisition and generalization of appetitive responding in obese and healthy weight females

Findings of a few recent studies suggest that obesity is characterized by deficits in appetitive learning about food cues. This could point towards an increased tendency in obese individuals to overgeneralize appetitive responding to stimuli that resemble the conditioned food cue – possibly explaining frequent eating desires and overeating in obesity. The current study aimed to investigate whether obese individuals 1) indeed exhibit appetitive learning deficits and 2) show overgeneralization of conditioned appetitive responses. Obese and matched healthy-weight females (N = 85) completed a differential appetitive conditioning task using food as rewards. First, appetitive responding to a novel stimulus was learned (acquisition phase), after which stimuli with varying resemblance to the food-associated stimulus were presented (generalization phase). Cue-elicited eating expectancies, eating desires, stimulus evaluations, and actual food intake were examined. Results indicated successful acquisition of appetitive responding across all outcome measures. The acquired responses also generalized, indicating that generalization can function as an additional mechanism by which learned food cues can promote food consumption. The data further suggested that overweight and obesity are not characterized by appetitive learning deficits nor by overgeneralization, but that a subgroup of obese individuals (those high in trait anxiety) may be more prone to overgeneralization of appetitive responding.