Toilet rooms, body massages, and smells: Two field studies on human evaluative odor conditioning

In two experimental field studies, the hypothesis was tested that Pavlovian conditioning may modify adults' liking or disliking of an odor. In Experiment 1, an odor (CS) was first paired unobtrusively with toilet stimuli (US). Next, Ss rated the experimental and a control odor on Semantic Differential items. For Ss evaluating going-to-the-toilet negatively, an acquired dislike for the toilet-paired odor relative to a nonexposed control odor was observed, whereas in Ss evaluating going-to-the-toilet positively, the reverse was observed. In Experiment 2, a neutral odor (CS) was mixed into the massage oil with which a physiotherapist treated his patients. Half of the Ss were treated with Positive-relaxing massage, half of the Ss with Negative-painful massage. At the medical follow-up, Semantic Differential ratings were obtained both for the treatment-odor and for a control odor. In the Positive massage group, the treatment odor was rated as more positive and as less dynamic than the control odor. No similar effects were observed in the Negative massage group, a failure which was probably due to the intended Negative massage not really being experienced as a disliked event. In both experiments, an almost identical pattern of results was observed in the subgroup of Ss who did not consciously recognize the experimental odor as the treatment odor, eliminating the possibility that the results should be due to demand. As mere exposure cannot account for the results, they most probably represent genuine instances of evaluative odor conditioning. The results are discussed in terms of the understanding of the origins of the affective meaning of odorants, and are related to human evaluative conditioning and implicit memory issues.