Implicit learning and implicit memory for odors: the influence of odor identification and retention time

One hundred and fifty-two subjects, divided into eight groups, were exposed to a room with a low concentration of either orange or lavender and to an odorless room. In a careful double-blind procedure, neither the subjects no r the experimenters were made aware of the presence of the odors in the exp erimental conditions. Later they were asked to indicate how well each of 12 odor stimuli, including the experimental and control odors, befitted each of 12 visual contexts, including the exposure rooms. At the end of this ses sion they rated the pleasantness and the familiarity of the odors, and iden tified them by name. Finally they were debrief ed and asked specifically wh ether they had perceived the experimental odors anywhere in the building. T he results of four subjects who answered positively to the latter question were omitted. The results confirm the earlier finding that non-identifiers implicitly link odor and exposure room, whereas identifiers do not show suc h a link. It is suggested that episodic information is an essential constit uent of olfactory memory and that its function is comparable to that of for m and structure in visual and auditory memory systems.