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March 03, 2005

"Oh God!!!" The proximate & the ultimate

I just recently read Why We Love: The Nature and Chemistry of Romantic Love, by psychologist Helen Fisher. I was interested in the "chemistry" part, as I've developed a mild interest in neurobiology and the various transmitters in the cranial "soup," and how they might impact our cognition (or lack of). It is a short, sweet, and at times a fluffy book (the chapters in the second half of the book start to veer into psychotherapy so I didn't pay as much attention to them). But, this hypothesis-just-so-story was worth reading the book, I thought:

  • When men and women look at beautiful/symmetrical faces the ventral tegmental area (VTA) tends to "light up" on fMRI.
  • The VTA is rich in dopamine, a neurotransmitter that induces energy & elation.
  • When women gaze at a symmetrical man as they are copulating the VTA lights up, produces dopamine, which triggers a release of testosterone, which enhances sexual response.
  • So, this explains why women achieve more orgasms with symmetrical men.
  • An organsm tends to "suck up" more of his sperm, increasing the possibility of fertilization.
  • And symmetrical men tend to have "better genes," so this integrated physiological set of responses fosters the ultimate end of greater fetal viability and health of the offspring.

So here you have a neat little story that connects the proximate dots, and also offers an ultimate explanation. Fisher could be wrong, but nevertheless, I thought it was worth sketching out her reasoning.

Related: Love & marriage & genes and Imprinters Walk Among Us.

Posted by razib at 06:40 PM