Associative learning and odor quality perception: How sniffing an odor mixture can alter the smell of its parts

Odors can acquire perceptual qualities from other odors with which they have been mixed. This finding was extended using new odorants and its constraints and mechanisms were explored. In Experiment 1, participants repeatedly sniffed two odor mixtures (AX/BY or AY/BX) and subsequently rated the perceptual qualities of each component alone. Odors experienced with X get to smell more of X (cherry-like and sweet) while odors experienced with A got to smell more of A (smoky). A further test revealed that odors experienced as a mixture were judged more alike than odors smelled an equal number of times, but not together as a mixture. Experiment 2 used a similar design with two new odors (CX/DY or CY/DX). The extent of perceptual quality exchange between mixture components (e.g., how X-like C became after CX pairings) was correlated with how similar the components were judged (e.g., X vs C). In addition, being able to identify the odor adversely affected learning. The nature of this process and its implications for odor quality perception and perceptual learning are discussed.