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you down with MHC?

Just read this interesting article in Time Magazine about how romance is linked to smell. We respond to olfactory cues and in fact, smell helps us narrow our choices of potential partners.

MHC (the major histocompatibility complex), a set of genes that controls the immune system and influences tissue rejection is especially critical. You jive best with a partner whose MHC is sufficiently different from your own. Studies show that couples with similar MHC’s have trouble conceiving or an increased risk of miscarriage.

A study had females smell various t-shirts worn by different anonymous men, then pick the one that appealed to them most. Most women chose ones worn by men with a MHC dissimilar to her own (=good). Those who chose the t-shirts worn by men with similar MHC (=bad) were on birth control. The daily dose of hormones confounds the MHC-smell detection system.

A chemist associated with the studies “wonders if the Pill may contribute to divorce… Women pick a husband when they’re on birth control, then quit to have a baby and realize they’ve made a mistake.” Here’s an in depth description of the study & a scientific explanation here.

Watch out Match.com, ScientificMatch.com is taking over. My friend Pavla read about this online dating service where you send in saliva samples and the program matches you with a mate with dissimilar immune system genes. Only $1,995.95 for a year for anyone except convicted criminals or women on birth control.

— dihard

Nice blog! Yeah, I am definitely down with MHC. There is still much to be discovered about hormones and olfaction. Some people in the field think PMS is fake, which is pretty ridiculous. None of them are female, by the way. And whoa, ScientificMatch.com sounds unbelievably shady! As if it is that simple. I’ll stick with sniffin’ somebody out.

There was one study, arguably the first solid study on human MHC odor preferences, which found that women prefer the smell of their fathers. The women in the study could identify their paternally-inherited gene for MHC. So, basically, we have an absolutely amazing and refined sense of smell, and we naturally select moderately similar/dissimilar genes. It’s like weighing inbreeding and outbreeding costs but not consciously. My friend Art, 60-something year old artist, just said to me yesterday that when a woman senses a great deal of chemistry with a guy, it always means that she wants to have his children. I didn’t argue with him, but I did ask him why he doesn’t have any kids.

— musicbrain

Musicbrain, great qualification on a topic the media loves to go crazy about - instant ramifications of genetic behavior data. Flies do it, and so do we! See, this one human study that looks at it in a roundabout way because that’s the only way possible confirms it! The roundup of this article doesn’t suggest it, but it stands confirming that we still don’t know for sure about human pheremones, and even once we do, their importance will probably be much more limited than they are in any other species. Scientists (myself included, I study stress and behavior and implications for depression and PTSD in rodents) always love to take choice out of human behavior. It’s interesting and fun, because as Americans we place such importance on personal choice and personal responsibility, it’s always crazy to think that maybe we aren’t as in control as we think, that our ‘subconcious’, to use a crappy term, is calling the shots. There is a whole industry trying to make money off of scientific research in this general area. For instance, a few years back at UCLA a scientist partnered with a company to do fMRIs on democrats and republicans to find out how they respond differently to political ads, with the hope of figuring out the innate differences in their brains so they could sell ads to political groups that either group would more strongly respond to for a huge fee. As if these political identities are distinct and separate organisms or something. Besides the fact that this is pretty much impossible to figure out in the first place, they had almost no idea what they were looking for, and besides the fact that I bet money no women were included in the study, as the pregnancy/possible pregnancy would rule them out, and women respond differently to everything emotional anyway, as the few fMRI studies that do include women show.

Anyway, lost my point almost. My point was that these olfaction studies are cool, and olfaction is one of the coolest areas of behavior research right now because of the ability to do so much genetic and behavior research at the same time in the same organism (flies), but every time studies get extrapolated to and performed in humans, capital BUTS need to be attached, even though theoretically it’s fun to take them away and eliminate all choice from human-human interactions. Cool thought exercise, interesting, and when we finally determine the extent of truth to how much we choose and how much our brain/genetics choose on its own, that will be cool. But, I worry that research and stories like this get digested by the government without qualifiers, and they then think, “see, birth control IS evil,” and then we all have to deal with another round of attacks on our access to birth control, except now they supposedly have Science backing them up.

So, thanks for covering a really cool cutting edge area of behavioral research, Time, but you suck.