Preference modulates smelling behaviour in olfactory decision tasks

When people are shown a pair of images and asked to identify which one is more attractive, their gaze shifts to the image they will eventually choose, prior to making the decision. Many researchers have examined the relationship between this gaze bias and decision processes, but not the relationships between other sensory modalities and decision processes. This study examined behaviour in relation to olfactory decision tasks. In accordance with the concept of gaze bias, the likelihood of participants smelling the item they eventually chose immediately before the decision was greater when they were instructed to identify an item that was more, versus less, favoured. The likelihood of smelling the item that was eventually chosen last was also greater than chance when participants were instructed to identify the more masculine item. These results suggest that a bias to sample a chosen item last is a common phenomenon regardless of sensory modality.