This study is often known as the "sweaty t-shirt study". In it, men each wore the same t-shirt for 2 days. The shirts were then put into identical boxes. Various women were asked to smell the shirts, and to indicate to which shirts they were most sexually attracted. The results showed that women were most attracted to men with an MHC most dissimilar from their own.
MHC and sexual selection
It has been suggested that MHC plays a role in the selection of potential mates, via olfaction. MHC genes make molecules that enable the immune system to recognise invaders; generally, the more diverse the MHC genes of the parents, the stronger the immune system of the offspring. It would obviously be beneficial, therefore, to have a system of recognizing individuals with different MHC genes and preferentially selecting them to breed with. Yamazaki et al. (1976) showed this to be the case for male mice, who show such a preference for females of different MHC. Similar results have been obtained with fish.
In a 1995 experiment by Wedekind, a group of female college students smelled t-shirts that had been worn by male students for two nights, without deodorant, cologne or scented soaps. Overwhelmingly, the women preferred the odors of men with dissimilar MHCs to their own. However, their preference was reversed if they were taking oral contraceptives. The hypothesis is that MHCs affect mate choice and that oral contraceptives can interfere with this. A study in 2005 showed similar results.
- Wedekind, C. et al. (1995). "MHC-dependent preferences in humans". Proceedings of the Royal Society of London 260: 245–49.
- *Furlow, Bryant., F. (1996). “The Smell of Love.” Psychology Today Mar/Apr.
- Scent of a Man - New Scientist Feb 10, 2001
- Elder, Rob. (2001). “The Science of Attraction,” Journal of Hybrid Vigor, Emory University, Issue 1.
- Boehm, T; Zufall, F. (Feb 2006). "MHC peptides and the sensory evaluation of genotype". Trends Neurosci 29 (2): 100–7. doi:10.1016/j.tins.2005.11.006. PMID 16337283.
- Wedekind C, Füri S. Body odour preferences in men and women: do they aim for specific MHC combinations or simply heterozygosity? Proc R Soc Lond B1997; 264: 1471–1479
- Wedekind, C.; Seebeck, T., Bettens, F. and Paepke, A. J. (1995). "MHC-dependent mate preferences in humans". Proc Biol Sci 260 (1359): 245–249. doi:10.1098/rspb.1995.0087. PMID 7630893.
- Santos, PS; Schinemann, JA; Gabardo, J; Bicalho Mda, G. (Apr 2005). "New evidence that the MHC influences odor perception in humans: a study with 58 Southern Brazilian students". Horm Behav 47 (4): 384–8. doi:10.1016/j.yhbeh.2004.11.005. PMID 15777804.