Tuesday, May 09, 2006

Neurology and sexual desire (paca)

This study just came through Yahoo News. It has the exciting and ultimately misleading title:

Study: Lesbians' Brains React Differently

I am always quite wary when I read an article like this. It is intended to be a biological study of sexual behavior and the article has a scientist saying something like, "we are likely to have more and more indicators in the future that many things related to sexual orientation have a biological basis." Apparently, this current research is a follow-up to a previous study on gay men, and I remember a study a couple years back about lesbian women blinking at different rates than straight women. In the current experiment they had women (and previously men) sniff certain chemicals, which may or may not be human pheromones. These pheromones may or may not have a relationship to sexual desire in humans, though they do in other animals. The scientists did a brain scan, probably functional MRI but the report doesn't say, to see which areas of the brain had increased blood flow while sniffing the chemical.

Now, it turns out that the lesbian women had a slightly higher activation rate in the hypothalamus than straight women did when sniffing the female pheromone. The article mentions that the hypothalamus is the base of a lot of sexual drive behavior. They don't mention that it is also the base of a lot of other things as well. For instance, long term memory goes through there to a large degree. Very likely the real research had a more specific region than the hypothalamus, but we don't know. There was less activation in the hypothalamus in straight women, who had instead increased activation in areas related to the general sense of smell instead. In short: lesbian women use sexual centers when sniffing female chemicals, while straight women use general smell centers like they might with a flower. This article and the blinking one always go on to say something to the effect of "lesbian women therefore behaved more like straight men." That sentence is always there. Of course, everyone knows that certain behaviors between lesbian women and straight men are similar - generally both think that Angelina Jolie is hot. But this neurological work seems to show that the basis for such beliefs about Angelina is biological, neurological, perhaps genetic, not social. Does it really show this? If you want to assess this article, you should ask a bunch of questions:

1) How did they define the subject pools precisely; i.e., how do you get the labels "lesbian" and "straight"? Is it "I fell in love/lust with this other girl 2 days after I hit puberty and it is all I have ever wanted?" Is it "I am attracted to women?" Is it "I kissed a girl 8 years ago?" Is it "I have thoughts about other women but I don't really want to act on them?" The point is that women don't come with sexual orientation labels stamped on their foreheads and the subject pools here could be almost anything. If a woman is madly in love with her boyfriend, but, sure, that woman at the coffee shop is pretty cute, which pool does she go into? Does one have to actually vomit when seeing a naked woman to go into the straight category or what? The actual research will have this spelled out. The popular news article does not.

2) What areas of the hypothalamus are involved exactly and what else do we know about them? Moreover, why exactly do we say there the hypothalamus is related to sex? To give a language example, for over a hundred years, psychologists thought this one area in the brain was particularly related to language syntax, grammar. In the last decade or so, we have discovered that we weren't asking quite the right question. That area really has more to do with processing long strings into chunks, kind of. It's not specific to language really at all; it's just that language has the sentences that you must decode. It is very, very likely that whatever the hypothalamus does is not exactly sex and sex alone. It could be that whatever makes women in today's society identify themselves such that they end up in a certain subject pool is not sex related at all.

3) How does the hypothalamus develop over the life span? Would we expect the same differences in pheromone behavior at infancy? At the age of 6? At puperty? Or does it fluctuate a lot throughout life?

I have a speculation. I bet that if you took straight men from, say, the highlands of New Guinea and showed them pictures of women who are particularly sexually attractive in their society, as well as pictures of some other ideal from another part of the world that they have no exposure to, I bet you would find different neurological activation patterns compared to American men. Does that mean that American men are biologically inclined to like one thing, while New Guinean men are not? Probably not. Because the human brain doesn't pop out of the womb complete. It continues to grow based on the experiences it has, and it is, on the face of it, equally possible that differences in hypothalamus activity are modified as people fall in and out of love with others. I am not denying that biology pushes our sexual desires in certain directions. Biology pushes the way language works, the way we hear music, the way we see, the way we imagine, everything. But it is almost certainly the case that there is no genetic or biological switch which stamps us forever in a certain way. Sexual desire changes as people grow. Some people love blondes and then 5 years later, they only want brunettes. And, believe it or not, the same thing is true about gender desires, though in a much deeper way than hair color. Here is a book that explores this issue in often heart-breaking stories (and yes I have read it).

Unexpected Pleasures: Leaving Heterosexuality for a Lesbian Life by Tamsin Wilton

So, anyway, I never said why studies like the ones reported here make me wary. They are studies to examine roots of sexuality and that's fine. Frequently, they are being done by lesbian or gay researchers. My main concern has always been that a search for a biological explanation for orientation is "the easy way out." The argument is that if orientation is biological then discrimination makes no sense. However, that avoids the apparently harder question for many, which is "If it is not biological, then is discrimination OK?" The biological question is easier because it is just updating your mental database with knowledge about the world. "I used to think the world was flat, then Magellan sailed around it and now I know it is round." That's a relatively painless change. I used to think something based on decent evidence and then I got new evidence. However, if orientation is not biological, then you have to question your own morals. "Apparently, I have always had all the evidence I needed and I was wrong about the way I acted." The latter is a much more difficult place to go.

Wow, I just think I did a rant. How'd that happen? OK, back to Micronesian language documentation.


I Krandall said...

Just a note: I think that one is not "born gay". I think that once trauma or PTSD occurs to a female her internal wiring tells her to look for abusive males, be smart and look for a kind man, or to discredit the male species completely and seek lesbian encounters or bi-sexualness.

pacatrue said...

Interesting speculation, i krandall. I think you have to be careful about something here. This view seems based on the view that bi or homosexuality is something like an alternative to heterosexuality, not a positive choice of its own. But it is equally, if not more, plausible that a certain orientation is not because of what someone doesn't like, but because of what they do. In other words, you could just as easily say that a woman has a totally wonderful experience at some point with other women and therefore continues to pursue that. So instead of something bad driving someone away; something good is attracting them.

To put it another way which ignores the whole orientation bit, imagine Man 1 who is very attracted to Woman X. Woman X, however, is happily dating Man 2. From Man 1's perspective, the most important aspect of his relationship with Woman X is that she is not dating him. So he wonders what's wrong with him. Why is she not choosing him? But really her dating of Man 2 has nothing to do with Man 1 at all. She actually likes Man 2 for a whole host of reasons. Man 2 is not the fall back plan to Man 1. Man 1 is not in the plans at all.

Anyway, my larger point is wariness on attempting to boil down a lifetime of desires, sexual and not, to any biological switch. I am equally wary of boiling down a lifetime of human desires to any single experience, traumatic or not. It would require that every lesbian woman endured some trauma in her life that was not endured by every straight woman. If 5% of the population is gay, that's 5 million American women or so who've all encountered this trauma.

pacatrue said...

To put my response more succintly, Debbie dating Jennifer might have as much to do with Debbie's view of men, as Angeline Jolie dating Brad Pitt has to do with her view of me, i.e. nothing.