Behavioral separation of liking and wanting in response to olfactory and visual food cues

In real-world settings, the appraisal of wanting (incentive salience) and liking (pleasure) of food rewards are processed in parallel across several sensory modalities, but paradigms that compare contributions of different modalities are lacking. Specifically, mechanisms by which odors contribute differentially to wanting and liking in food reward valuation remain poorly understood. This study addresses this gap by separating wanting and liking of olfactory and visual stimuli and comparing their valuation across the two modalities. In two separate experiments, participants rated content-matched batteries of odors and pictures, respectively, for their ability to elicit pleasure (liking) and the desire to eat (wanting). Each battery was reduced to a set that clearly separated the two components and then validated in a third experiment using a combined olfactory-visual paradigm. Our results show that participants differentiated clearly between liking and wanting in both sensory modalities, as demonstrated by a high difference score between the two in non-food, but not in food or disgusting stimuli. Visual stimuli were associated with more extreme ratings and higher non-food difference scores compared to odor stimuli, implying a higher risk of odor misidentification. These findings indicate it is possible to behaviorally separate reward components by stimulus category within both the olfactory and visual modalities. Our stimulus set provides a basis for more complex experimental designs that can manipulate these factors independently. This could provide novel insights into the individual contributions of visual and olfactory cues to anticipatory food reward, the integration of sensory reward valuation with gastrointestinal feedback, and their independent roles underlying food reward processing, not only in healthy individuals but also in individuals with dysregulated processing of food reward, such as those with disordered eating and eating disorders.