Does good+good=better? A pilot study on the effect of combining hedonically valenced smells and images

Responses to affective stimuli are usually studied in just one sensory system at a time. However, this is rarely the way they are experienced. We were interested in how combining affective stimuli of similar intensities across two sensory modalities (smell and vision) would affect both behavioral responses (ratings) and psychophysiological responses (skin conductance). We studied this using olfactory stimuli delivered birhinally while the subjects viewed affectively laden scenes on a computer screen. Bilateral skin conductance recordings were taken throughout. Subjects rated the pleasantness of the images that they were viewing. We found a particularly salient effect of unpleasant smells, which enhanced the pleasantness ratings of certain images and also the skin conductance responses to unpleasant images.