Researchers from the University of Chicago performed a study regarding human body scents and "preference" . Interestingly enough, this was due to association of MHC allele matches.....
In the first study in preliminary tests, women were allowed to choose between boxes with body scents on fabric, and were asked which they preferred or would avoid. Women preferred scents of men with whom they shared some MHC alleles and avoided boxes with which they shared no MHC alleles. Beyond this, scientists tested the hypothesis that choice was mediated by emotions, and not familiarity of smell. So women rated boxes from male donors (plus controls). They rated familiarity and intensity, pleasantness and spiciness. Women were blind from knowing these scents were male derived. Results indicated that women preferred donors with HLA alleles which match paternal alleles and avoided scents with no match, and this was based on pleasantness of scent and not familiarity, intensity and spiciness.
In the second study, scientists examined body scents from breastfeeding women and their infants. It was known from previous studies that scents from the breasts and axillae(armpit) of breastfeeding moms increase sexual motivation, and alter timing of ovulation in other women. This group wished to elucidate whether these effects were from immediate olfactory experience when the scents were wiped under her nose. Women either had control pads or compounds collected on pads from breasts and axillae of lactating women wiped under their noses. The women were asked questions about preference or strength of smell, or if it affected their moods. Results did not prove that smelling scents from women caused changes in menstrual cycle length or sexual desire.
Ladies, it looks like we prefer to smell men that smell like our dads and if we hang around pregnant women will cause us to want more sex and and change our ovulation patterns. Personally I do not know how I feel about this- but it may explain a few things......
Here is the citation-
ReplyDeleteChem. Senses 30(suppl 1):i135-137. 2005
That is amazing; I never expected it to be true in humans, who generally have poor senses of smell. Years ago it was shown that mice could learn to turn left in a T maze when there was a drop of urine there. But most interestingly, they could learn to distinguish between 2 drops (one right, one left) which differed ONLY at MHC (the researchers used urine from congenic strains bred so that only MHC differed). OK, they're mice, smell is a big deal; but humans? And why shared MHC--don't we want to keep on being outbred?
ReplyDeleteYou would think it would be illogical, due to inbreeding, but indeed that is what is in the study. Although, preference for scents with matching MHC alleles were considered more "pleasant". They did not say anywhere that there was a correlation between smelling samples that smell like "dad", and correlating that with sexual excitement. Maybe it could be inferred that dad smells pleasant, and women are capable of identifying who has similar MHC alleles based on this, to perhaps find a partner who doesn't smell like dad? And maybe this is an unconscious activity that women do?
ReplyDeleteThis was a study from the dept. of psychology out of Univ. of Chicago. I really think it is more complicated than what is presented in this study
It would make sense that women would be attracted to scents that smell like their fathers, associating that smell with love, caring and support. I wonder though if this would also be true with women whose fathers weren't present in their life, or whose fathers were abusive or a negative influence on their life. I wonder how much of being attracted to a smell was due to familiarity (I know they said it wasn't familiarity, but how can they accurately control for that?) and how much was really due to distinguishing specific MHC alleles. Is it an association mechanism or something else entirely?
ReplyDeleteMarie brings up an interesting point about women with neglectful fathers. I wonder if it would actually make a difference though. The conclusion I drew from Adelita's description was that MHC alleles from one's father would be considered "fit", given that that man was able to procreate and pass on his alleles to the woman under study. Different alleles unknown to the smeller, however, would indicate nothing about Darwinian "fitness"; so I believe that these results may be supported by a follow-up studying women with neglectful fathers. That being said, I think there are a number of psychoemotional issues inherent to children of abusive parents that would need to be controlled for in that study.
ReplyDeleteGood find Adelita - it certainly would help explain a lot ....
Considering Darwinian fitness, what would attract these women to further inbreed their MHC alleles to be more homozygous? It seems if anything, they would want to increase the genetic variability of their MHC alleles the same as any other alleles. Not that one would want to outbreed these genes and completely rid themselves of a potentially perfect MHC, but it seems it would be a compromise.
ReplyDeleteThis is not the first time I have heard about this phenomena! A while ago, I remember reading about a study that had women who were ovulating smell various white cotton t-shirts that belonged to male subjects. The only scent each shirt possessed was that of the unique smell each man gave off. Women would smell the shirt and record whether or not they were attracted to that man based of their scent. It initially seemed so bizarre to me! It would be interesting to have the same woman smell the same shirt once when she's ovulating and once when she isn't to record any differences in attraction. Odds are, she'd be attracted to him during ovulation and not attracted to him when she wasn't. This would further verify that women really DON'T know what they want! ;)
ReplyDeleteI have also heard sometimes ovulating women unknowingly put themselves out there more to men by dressing more provocatively, wearing more makeup and behaving differently. It retrospect, it is their way of saying, "Hi. My eggs are dropping and I'm somewhat aroused :)" So interesting! I would really enjoy reading studies that examined this.