Stress Increases Cue-Triggered “Wanting” for Sweet Reward in Humans

“Stress increases reward-seeking (i.e. wanting) but not reward enjoyment (i.e. liking). Chocolate-lovers who were stressed by putting their hands in ice water exerted 3x as much effort to be able to smell a chocolate odor than those who weren’t stressed, but they didn’t enjoy the experience any more.”

Stress can increase reward pursuits: This has traditionally been seen as an attempt to relieve negative affect through the hedonic properties of a reward. However, reward pursuit is not always proportional to the pleasure experienced, because reward processing involves distinct components, including the motivation to obtain a reward (i.e., wanting) and the hedonic pleasure during the reward consumption (i.e., liking). Research conducted on rodents demonstrates that stress might directly amplify the cue-triggered wanting, suggesting that under stress wanting can be independent from liking. Here, we aimed to test whether a similar mechanism exists in humans. We used analog of a Pavlovian-Instrumental Transfer test (PIT) with an olfactory reward to measure the cue triggered wanting for a reward but also the sensory hedonic liking felt during the consumption of the same reward. The analog of a PIT procedure, in which participants learned to associate a neutral image and an instrumental action with a chocolate odor, was combined with either a stress-inducing or stress-free behavioral procedure. Results showed that compared with participants in the stress-free condition, those in the stress condition mobilized more effort in instrumental action when the reward-associated cue was displayed, even though they did not report the reward as being more pleasurable. These findings suggest that, in humans, stress selectively increases cue-triggered wanting, independently of the hedonic properties of the reward. Such a mechanism supports the novel explanation proposed by animal research as to why stress often produces cue-triggered bursts of binge eating, relapses in drug addiction, or gambling. (PsycINFO Database Record (c) 2014 APA, all rights reserved)

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Eric Write head editor and chief at The Pluto Daily