Major histocompatibility complex-associated odour preferences and human mate choice: near and far horizons

Abstract

The major histocompatibility complex (MHC) is a core part of the adaptive immune system. As in other vertebrate taxa, it may also affect human chemical communication via odour-based mate preferences, with greater attraction towards MHC-dissimilar partners. However, despite some well-known findings, the available evidence is equivocal and made complicated by varied approaches to quantifying human mate choice. To address this, we here conduct comprehensive meta-analyses focusing on studies assessing: (i) genomic mate selection, (ii) relationship satisfaction, (iii) odour preference, and (iv) all studies combined. Analysis of genomic studies reveals no association between MHC-dissimilarity and mate choice in actual couples; however, MHC effects appear to be independent of the genomic background. The effect of MHC-dissimilarity on relationship satisfaction was not significant, and we found evidence for publication bias in studies on this area. There was also no significant association between MHC-dissimilarity and odour preferences. Finally, combining effect sizes from all genomic, relationship satisfaction, odour preference and previous mate choice studies into an overall estimate showed no overall significant effect of MHC-similarity on human mate selection. Based on these findings, we make a set of recommendations for future studies, focusing both on aspects that should be implemented immediately and those that lurk on the far horizon. We need larger samples with greater geographical and cultural diversity that control for genome-wide similarity. We also need more focus on mechanisms of MHC-associated odour preferences and on MHC-associated pregnancy loss. This article is part of the Theo Murphy meeting issue ‘Olfactory communication in humans’.

Human olfactory dysfunction: causes and consequences

“…Bonding difficulties are associated with the inability to recognize the own baby’s odour, and mothers with impaired bonding do not perceived their own child’s odour as pleasant as healthy mothers (Croy, Mohr, Weidner, Hummel, and Junge-Hoffmeister ( 2019 )). Mate choice and romantic relations are also influenced by olfactory cues (for a review, see (Mahmut and Croy 2019 ), as they impact attractiveness perception, presumably dependent on genetic (e.g., Sorokowska et al ( 2018 ) or for review (Havlíček, Winternitz, and Roberts 2020 )) or hormonal traits (Lobmaier, Fischbacher, Wirthmüller, and Knoch 2018 ). With regard to sexuality, olfaction contributes to quality and quantity of sexual behaviour (Bendas, Hummel, and Croy 2018 ) and the experience of sexual arousal is mediated by body odour perception (Cerda-Molina, Hernández-López, Claudio, Chavira-Ramírez, and Mondragón-Ceballos 2013 ).…”

Physical cues of partner quality

“…Evidence that people find the body odour and faces of MHC-dissimilar partners more attractive is mixed, with studies finding both preferences for more MHC-dissimilar (Sorokowska et al, 2018) and preferences for more MHC-similar (Coetzee et al, 2007;Roberts et al, 2005) potential partners. Recent meta-analyses suggest that the evidence is either currently marginally in favour of preferences for MHC-dissimilar potential partners' odours and faces (Winternitz et al, 2017) or supporting no effect in either direction (Havlíček et al, 2020).…”

The specific biochemistry of human axilla odour formation viewed in an evolutionary context

“…This has indeed been postulated [51], but its stands in stark contrast to what we know on the physico-chemical nature of odourants in general and on the chemistry of body odours specifically [52]. Thus, even if the hypothesis that odours may communicate information about a 'matching immune system' to sire more pathogen-tolerant offspring is tempting, it still needs to answer a number of crucial questions (see also Havlícěk et al [53]).…”