There’s something new from the world of sweaty tee shirts, and I’m excited--because it says something powerful about our human nature.
It’s about romantic compatibility, in this case “MHC” compatibility. MHC means Major Histocompatibility Complex and it refers to a particular set of genes you inherit in your immune system, your body’s chemical defense system against intruding aliens, aliens in the form of bacteria, viruses and other no-good-niks. Each of us inherits our own version of this complex set of genes.
In a classic study, women were given men’s tee-shirts to sniff. And to the astonishment of many scientists, women preferred those worn by men with a different set of MHC genes than their own. They distinguished this by smell. This unconscious preference probably discourages “inbreeding” with close relatives and can create a stronger immune system in one’s young.
But get this. Scientists have now looked at MHC compatibility among romantic couples and they report that the more genes in this system that a couple share, the more sexually unfaithful the woman is and the more she is attracted to other men during in the middle of her menstrual cycle—when she is ovulating and likely to get pregnant.
I’m not excited about adultery, hardly. But this new study supports a theory I have about romantic love, a theory at the core of my endeavor to match members of the new Internet dating/relationship site, Chemistry.com.
This endeavor began two years ago when Match.com came to me and asked me why we fall in love with one person rather than another. There are many forces that guide attraction, of course. We tend to be attracted to those of the same ethnic and socio-economic background, as well as those with a similar intelligence, good looks and religious values. We also fall in love with those who supply our needs. And certainly your childhood plays a role. But when scientists administer personality tests to long-married couples, NO patterns of personality similarity or differences emerge.
So after a good deal of reading, I came to believe that humans fall into four very broad genetic types, what I call the Explorer, Builder, Negotiator and Director--each associated respectively with the activities of dopamine, serotonin, estrogen and testosterone. Moreover, I theorized that we are regularly attracted to individuals (from our background) who have a different genetic profile. This way partners can bear more varied young and co-parent with a wider array of parenting skills.
Today some 1.6 million men and women have joined Chemistry.com, (a sincere thanks to them), and I have collected data on the first 523,622. And from the ways these men and women have answered the questions I devised to join the site, it appears that we are attracted to those who are genetically different from ourselves—in more ways than just MHC compatibility!
In short, these new data on MHC compatibility suppport my theory and boost my conviction that the folks at Chemistry.com can match men and women more effectively using a biological approach (as well as the standard means of matching).
Equally important to me as a scientist, we are beginning to understand nature’s blueprint for mate choice—one of the most profoundly important decisions we make in life.
Semper ad astra, Helen Fisher.