Abstract
This experiment aimed to investigate the effect of description about odor on perception of the odor. An odor stimulus (anethol) that was unfamiliar with Japanese culture was presented with a description about the odor to participants. Half of the participants (positive group) received a positive description about odor, and the other half (negative group) received a negative description about the odor. As a positive description, the experimenter sharpened a positive aspect of the odor description, such as “used as spice” and “used in aromatherapy”. On the other hand, as a negative description, the experimenter sharpened a negative aspect of the odor description, such as “used as pesticide” and “harmful to organisms”. Participants smelled anethol in the MRI laboratory while their brain responses to the odor were recorded. Participants in the positive group rated the odor as more pleasant and more intense than those in the negative group. The activation areas were different between groups. The activated areas of participants in the positive group were found in the insula, which were known to be involved in positive emotion evoked by pleasant odors. On the other hand, the activated areas of participants in the negative group were found in the anterior cingulate cortex and amygdala, which were known to be involved in processing negative emotions. It is suggested that brain mechanisms, such as reported in this study, underlie individual differences in odor perception.
