Evidence for odour-mediated assortative mating in humans: The impact of hormonal contraception and artificial fragrances

Abstract

There is substantial evidence for assortative partner preferences in humans based on physical characteristics. In contrast, evidence suggests that olfactory preferences tend to be disassortative, with people preferring body odour of potential partners who are dissimilar at key genetic loci, perhaps to gain fitness advantage through offspring heterozygosity. We compared ratings of perceived body odour similarity of real couples with those of randomly paired 'fake' couples. Contrary to prediction, we find that odours of real partners are perceived more, rather than less, similar to each other than fake couples. However, this applied only to natural odour samples: there were no differences in similarity levels of real and fake couples' samples which were collected while wearing artificial fragrances. Furthermore, in light of suggestions that hormonal contraception (HC) disrupts disassortative odour preferences in women, we compared odour similarity among real couples in which the female partner was using or not using HC at the time when the relationship began. We find that odours of HC-using couples are of intermediate similarity between non-using and fake couples, suggesting that HC use during partner choice could affect odour-influenced assortment. We also examined the association between relationship satisfaction and perceived similarity of unfragranced odours of real couples. We found that these are positively correlated in male partners but negatively correlated in the female partners, indicative of a sex difference in the relative favourability of odour similarity in partner preference. Finally, by comparing odour similarity ratings with those given by perfumers using a novel olfactory lexicon we found evidence that similarity judgements were based on the Spicy/Animalic aspects of individual odour profiles. Taken together, our results challenge the conventional view that odour-mediated partner preferences in humans are typically disassortative.

No Evidence That Hormonal Contraceptives Affect Chemosensory Perception

“…On the other hand, OC has been linked to lower olfactory sensitivity for musk-like odors (as indicated by higher detection threshold levels; Caruso et al, 2001;Renfro & Hoffmann, 2013), as well as lower sensitivity for social odors, but simultaneously higher sensitivity for environmental odors (Lundstr€ om et al, 2006). Also, OC seems to change partner body odor preference in women, shifting it from preferring the odor of men with a different major histocompatibility complex than oneself to men with a more similar major histocompatibility complex (Allen et al, 2019;Roberts et al, 2008;Wedekind et al, 1995). Similarly, withdrawal of OC has been linked to reduced discrimination for body odors, whereas no effects were found for ordinary odorants (Endevelt-Shapira et al, 2020).…”

Canine Smell Preferences—Do Dogs Have Their Favorite Scents?

“…Even though the human sense of smell is much less sensitive, and olfaction seems to play a much lesser role in our lives compared to that of animals, and particularly dogs, there is a surprisingly high number of publications dedicated to smell preferences in humans, compared to the extremely low number of similar publications dedicated to dogs [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. Further, in other species, such as mice, in which olfaction plays a crucial role in many aspects of life, there are a number of publications related to olfaction, including smell preferences [ 22 , 23 ].…”