The acquisition of odour qualities

Odours can evoke a large range of qualities. Some of these qualities (e.g., sweetness) appear to be acquired through simultaneously experiencing odours mixed with tastes. Acquisition might also occur when two odours are experienced as a mixture. In this case mixture components might acquire each other's qualities. This was tested in two experiments. In the first, subjects repeatedly sniffed two odour mixtures (either AX, BY or AY, BX). Odours mixed with A acquired A's properties and were judged more similar to A than to B. Odours mixed with B were not clearly discriminable. The second experiment used a similar approach except that Odour B was replaced. Subjects now smelled either AX, CY or AY, CX. All components were discriminable. Odours mixed with A acquired A's properties and were judged more similar to A than to C. Although odours mixed with C did not acquire C's qualities due to a confusion of quality terms, odours previously mixed with C were judged as more similar to C than to A. Evidence of other quality exchanges were also obtained. These results suggest that pure odour qualities can be learnt and lend support to William James's (1890) notion of the acquired equivalence/distinctiveness of cues.