Multimodal Interactions: Color-Chemical

Influence of Color on Odor

Certain colors seem to go with or correspond to certain odors. For example, people find that more intense odors correspond to darker colors. Some specific correspondences have been found between particular colors and the odors of compounds used in perfumes. For example, people indicate a correspondence between the smell of cinnamic aldehyde (cinnamon) and the color red, whereas they indicate a correspondence between caramel lac-tone (caramel) and the color brown. Even complex perfumes have corresponding colors. Perfumes perceived as masculine correspond to blue and perfumes perceived as feminine correspond to pink.

These correspondences are not fully understood. Some might result from learned associations between the color and the odor. For example, after repeatedly seeing an orange-colored solution prior to smelling its orange odor, a person might come to associate the color and odor. Some connections may be innate and reflect a type of synesthesia. How these correspondences might affect people's perception of odors is discussed next.

Visual input, particularly color, helps us identify odors. We have difficulty identifying an odor when the color of the odorant is masked or altered. For example, a cherry-flavored drink colored orange is often misidentified as being orange-flavored (cherry rather than orange being the odor component of the drink). Similarly, red birch beer is often misidentified as cherry soda and white wine colored red is misidentified as red wine. In addition, we are able to identify orthonasal odors both more accurately and more quickly when the color of the stimulus is more appropriate to the odor.

Color can also affect pleasantness by affecting identifiability. For example, grape odor is more often identified correctly and found to be more pleasant when colored purple than when colored yellow. This increase in pleasantness with identifiability might be related to the fact that people find familiar odors more pleasant than unfamiliar ones. Enhanced identifiability contributes to familiarity, thereby increasing pleasantness. Brain areas associated with the hedonic evaluation of odors are more strongly activated by appropriately colored than by inappropriately colored odors.

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