There is increasing evidence that human body odor is involved in interpersonal communication. However, among the wide variety of substances excreted by the human body that might act as chemosignals, much attention has been granted to androstenes to the detriment of other categories. Here, we focused on the acidic fraction of human body odor. We investigated men and women's perceptual descriptions and detection thresholds of the sexually dimorphic (male) compound 3-hydroxy-3-methylhexanoic acid (HMHA) in two contrasted cultures, France and Madagascar. Perceptual responses to HMHA in both countries were very similar. HMHA proved to be more typical of body odor than another chemically-related major compound of human body odor 3MHA (3-methylhex-2-enoic acid also known as 3M2H). A significant portion of the samples studied (between 8 and 19%) was likely to be anosmic to HMHA (and to 3MHA: 25%). Although differences would be expected between men and women's perceptual responses to HMHA, based on the assumption that this compound would have a function in human partner choice, no sex differences were found for any of the perceptual variables. However, in Malagasy women, perceived intensity of HMHA was higher in participants who were in the fertile phase of the menstrual cycle. Whether HMHA is relevant in the perception of a potential partner thus requires further explorations, with more implicit approaches for example and/or by investigating the repercussions of HMHA specific anosmia on interpersonal relationships.
Keywords: Body odor; Chemical communication; Cross-cultural study; Gender differences; Odor threshold; Social interaction.
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