CONTEXT-DEPENDENT CHANGES IN THE PERCEPTION OF ODOR QUALITY

Ambiguous odor compounds, partly citrus-like and partly woody in odor character, were seen to change in odor quality when evaluated in the same session as more prototypical odors. When tested with characteristically citrus odors, the ambiguous compounds seemed more woody. and when tested with characteristically woody odors, the ambiguous odorants were higher in citrus character, an example of perceptual contrast. Response frequency biases were ruled out as an explanation for this shift by, an experiment in which responses other than citrus and woody ratings were asked of the subjects during the contextual exposure. Simple sensory adaptation was found to be a potential contributor to the effect, and a sufficient condition to produce similar shifts in odor quality. However, adaptation was not a necessary condition to produce the effect. This was seen in reversed pair experiments in which the contextual odors were presented after the ambiguous stimuli. The contextual shift was robust-it was obtained with different ambiguous odors. contextual (conditioning) odors, numbers of contextual odors, orders of presentation of contextual odors relative to ambiguous odors, scale types, and rating tasks during the presentation of contextual odors.