Pavlovian conditioning to hedonic food cues in overweight and lean individuals.

Obese individuals develop heightened reactivity to environmental cues associated with hedonic foods through Pavlovian conditioning. This study examined differences between overweight (n = 16) and lean (n = 17) 18-26 year-olds in their acquisition of a swallowing response to visual cues paired with chocolate milk, tasteless water and no taste stimulus. We hypothesized that, compared to lean participants, overweight participants would demonstrate a heightened conditioned swallowing response to the visual cue paired with chocolate milk as well as a resistance to extinction of this response. Results showed that overweight participants swallowed more in response to the visual cue previously paired with chocolate than the cue previously paired with tasteless water (t(15) = -3.057, p = .008) while lean participants showed no cue discrimination (t(16) = -1.027, p = .320). The results evaluating the extinction hypothesis could not be evaluated, as the lean participants did not acquire a conditioned response. In evaluating the conditioned swallow response of overweight participants only, results indicated that there was not a significant decrease in swallowing to cues paired with chocolate milk or water, but overall, overweight participants swallowed more to cues paired with chocolate than cues paired with water. These are the first results to show differential acquisition of Pavlovian conditioned responding in overweight individuals compared to lean individuals, as well as differential conditioning to cues paired with hedonic food stimuli compared to cues paired with neutral stimuli.