The summer holiday is officially over for me, but I haven’t been able to resume blogging on account of being in lovely Ljubljana for ESSLLI this week (today I gave a talk at the logical constants workshop). So still not much time for blogging, but there is one article which I came across last week and would like to talk about, with the admittedly not so felicitous title "Sex on the brain: What turns women on, mapped out". (Quite a change from London riots!) Here is how it starts:
It's what women have been telling men for decades: stimulating the vagina is not the same as stimulating the clitoris. Now brain scan data has added weight to their argument. The precise locations that correspond to the vagina, cervix and female nipples on the brain's sensory cortex have been mapped for the first time, proving that vaginal stimulation activates different brain regions to stimulation of the clitoris.
The sensory cortex is the part of the brain where neurons connected to different parts of the body receive and exchange information on sensory input received by each body part. It may seem somewhat surprising that there should be an exact part of the brain that processes the sensory input to one’s arm, for example, rather than it being a more holistic, diffuse process. But this is indeed what began to emerge from experiments performed during brain surgery on conscious patients back in the 1940s, and since then confirmed by more ‘sophisticated’ techniques. In 1951, the first ‘map’ of how different parts of the body were connected to different areas of the sensory cortex was published – a scheme referred to as the ‘homunculus’ – but guess what: all subjects were men, and thus there was no cortical mapping of the female sexual organs!
It was only last year that a group of researchers in Zurich investigated female subjects. And what did they find out? Surprise, surprise: “the position of the clitoris on the homunculus was in approximately the same position as the penis in men.” From an embryological point of view, this is no surprise at all, as it is well known that the same tissue that eventually develops into the penis in the case of male individuals ends up becoming the clitoris in female individuals. In fact, in the first weeks of the development of the embryo (around 8 weeks in humans, if I’m not mistaken), the tissue is undifferentiated and has the exact same morphology in male and female individuals.
So, from which point of view is this conclusion surprising, if any? Well, from the point of view of pretty much all traditional conceptions of female sexuality, which are for the most part clumsy adaptations of male sexuality – culminating with uncle Freud, of course. (Let me add that the 'binary' should certainly not be understood as exclusive and clear-cut; see for example the work of Alice Dreger on what she calls ‘intersex’ individuals.) The underlying idea could be described as a ‘functionalist fallacy’: since men’s sexual organ is the penis, and the penis also has a reproductive function, then ‘obviously’ the female sexual organ should be the female (external) reproductive organ, the vagina. Hence, just as men experience sexual pleasure predominantly through penis stimulation, so should women (in any case the ‘mature ones’, according to Freud) experience pleasure predominantly through vaginal stimulation. It is only with Masters and Johnson in the 1960s that this picture started to be questioned, and that due emphasis was given to the role of the clitoris in female sexuality. But then again, it’s been 50 years, which makes it even more astonishing that the exact location of the area corresponding to the clitoris in the sensory cortex was investigated only in the 2010s. Clearly, uncle Freud is still with us.
But arguably, he was as wrong as wrong can be on this one (I know I tend to be overly harsh on Freud, but his account of female sexuality is just infuriating, and has rightly infuriated generations of feminists). The concept of ‘penis envy’ in particular is an absurdity; in fact, women do have a penis, namely their clitoris (which in fact isn’t even considerably smaller than the penis as one might think: most of it is inside the body), and if young girls do experience something resembling ‘penis envy’, as hypothesized by Freud, it has no biological basis: it is a product of misinformation and cultural oppression. Indeed, we could just as well say that men have a clitoris, except that it’s mostly external (besides other morphological differences such as the position of the urethra). As feminists such as Betty Dodson have been arguing for years, it is the clitoris, not the vagina, that is a woman’s primary sex organ, and this is confirmed by embryology, neuroscience, and in practice by many (though sadly not all) women around the world.
And while I’m at it, let me recommend the wonderful work of philosopher of biology Elizabeth Lloyd, who to my mind ‘cracked’ the puzzle of the evolutionary function of the female orgasm: none. According to her, it is a by-product of the evolution of the penis, precisely because the penis and the clitoris are each other’s morphological counterparts. (Interestingly, her views have infuriated lots of feminists too, and stirred a small polemic over at Leiter’s blog a few years ago.)
UPDATE (August 11th): WildlyParenthetical's comments over at her blog (link in comments below) made me realize that there was a potential source of confusion in my original post: as I understood it, the fMRI study in question was never intended to map *arousal* 'on the brain', but simply to identify which parts of the sensory cortex processed sensory information received by the clitoris, vagina and nipples. The women were not asked to stimulate these parts so as to get aroused (as if it was that simple...), but merely to touch them so that the researchers could see which areas of the sensory cortex reacted to the fact that these parts were receiving sensory stimulus. Arousal is of course a vastly more complicated process both for women and for men, certainly coming about in a variety of different ways, as pointed out by WildlyParenthetical. This is one of the reasons why the title of the article is infelicitous; it's not about "mapping out what turns women on", but simply about mapping neuronal sensory connections.