THE ROLE OF PERCEPTUAL AND STRUCTURAL SIMILARITY IN CROSS-ADAPTATION

Cross-adaptation, the decrease in sensitivity to one odorant following exposure to a different odorant, is affected by odorant similarity, b oth perceptual and structural, but the precise relationship is obscure . The present series of studies was designed to explore various aspect s of perceptual and structural similarity as they relate to cross-adap tation. In Experiment 1, cross-adaptation was assessed between androst enone and five odorants that share a common urinous note with androste none, but retain unique perceptual characteristics; only the compound judged most perceptually similar to androstenone cross-adapted it. In Experiment 2, odorants both perceptually and structurally similar (and rostenone and androstanone) displayed significant mutual cross-adaptat ion. Furthermore, magnitude estimates for androstanone were significan tly reduced following exposure to 3-methylidene-5 alpha-androstane (3M 5A), a structurally similar, perceptually odorless compound. This find ing appears to be the first demonstration that an odorless compound ca n affect, via cross-adaptation, the perception of an odorous compound. Finally, in Experiment 3, significant, asymmetric Cross-adaptation wa s observed between compounds that are perceptually and structurally di ssimilar (4-cyclohexylcyclohexanone [4-CHCH] and androstenone). These findings indicate that the role of similarity in cross-adaptation.