Concerning memory processes in olfaction, most of the authors herein note that the evidence is sparse, mainly because the standard procedures used in the fields of vision and hearing are difficult to transfer to olfaction. Early research in olfaction, mimicking studies of the processing of visual information, was oriented toward episodic and semantic functions. However, recently there has been increasing interest in olfaction specificity, therefore shifting the focus to implicit forms of odor memory and to priming effects.

Chapter 13, by Sylvie Issanchou and colleagues, explains how the study of odor memory specificity in everyday life led them to contrast (1) incidental (nonintentional) learning and implicit recollection and (2) consciously learned and consciously recollected memories of odors in laboratory studies. They examine the ecological validity of traditional laboratory experiments and of incidental-learning paradigms in the study of olfaction by trying to get at the experimental conditions that can best predict memory performances in everyday life. They prefer priming and same/different judgments to identification tasks. However, Issanchou and associates, like Maria Larsson (Chapter 14) and Mats Olsson and his colleagues (Chapter 15), note that in spite of their efforts, it has been unexpectedly difficult to show priming effects in olfaction, as compared with priming in other modalities, the challenge being to figure out whether priming effects depend on perceptual processes or on conceptual (naming) processes.