David Linden - Touch

Figure 4.4Using a brain scanner to map the regions of somatosensory cortices activated by self-stimulation of the external clitoris, vagina, cervix, toe, and nipple. Note that nipple stimulation produced activation that overlapped with that of the cervix, vagina, and clitoris. This might underlie the role of the nipple in women’s sexual sensation. To date, this experiment has not been performed with male subjects. Another issue to bear in mind is that it’s not possible to stimulate all genital regions in isolation using a dildo. Stimulation of the vagina will certainly activate the base of the clitoris, which presses against the anterior vaginal wall; stimulation of the cervix will undoubtedly involve some activation of both the vagina and the clitoris; and all of these forms of genital stimulation will produce some stretching of the labia minora and the perineum. Adapted from B. R. Komisaruk, N. Wise, E. Frangis, W.-C. Liu, K. Allen, and S. Brody, “Women’s clitoris, vagina, and cervix mapped on the sensory cortex: fMRI evidence,” Journal of Sexual Medicine 8 (2011): 2822–30, with permission of the publisher, Wiley.

When I was in the fourth grade, the boy sitting at the desk next to mine was named Ralph. Even at ten years old, he was one of those kids who you knew was going to eventually wind up in prison. Ralph fought with everyone. He loved to draw sloppy pictures of motorcycles on his filthy arm with ballpoint pen and had a perpetually runny nose that he never wiped. One day, apropos of nothing, he leaned over and said to me, “You know how girls get pregnant? They take off their pants— sniff —and a boy takes off his pants— sniff —and then they rub their butts together. Then she’ll have a baby.” At that point in time the precise details of sex were still a bit vague to me, but I knew that this couldn’t be right. Ralph continued with his sexual riff: “You know what a boner is? If you think about naked ladies— sniff —then your dick will get stiff, and that’s called a boner.” To me, this explanation seemed equally suspect. A boner, as I knew, was a tangible, concrete thing, while a thought—of naked ladies or anything else—was wispy and fleeting and clearly not of the physical world. How could one have anything to do with the other? They were in different realms. His explanation smacked of mysticism and, worse, superstition.

“No way,” I said.

“Way,” said Ralph.

Let’s imagine that you’re walking down Waverly Place in New York City’s West Village. You’re hungry and a bit tired. You see someone walking by carrying a falafel sandwich, one of your favorite foods. Then, moving along, you spot the source of the falafel, Taïm, a tiny, crowded restaurant. You can smell the delicious odors of frying falafel balls, harissa, and tahini sauce, and you begin to salivate. You walk in and order a falafel sandwich. A few minutes later, you take that first crispy bite, which is so very good. You take another, and because it’s a big sandwich, as you continue to eat, you begin to feel sated. The pleasure from the last bite is fine but not nearly as good as that first bite. Now you’re full up and unlikely to eat again for a while. Unless, perhaps, there’s some good sorbet to be had over on Prince Street.

In true nerdly tradition, if we were to graph this pleasurable eating experience (pleasure on the y -axis, time on the x -axis), it might look something like figure 4.5. There’s an initial phase in which the sight and smell of food interact with your internal state (hunger) to create desire. You’re already feeling some pleasure at this point, and in anticipation of more you begin to salivate. Importantly, this desire reflects both hardwired and learned responses. We humans are hardwired to respond favorably to certain food odors, including those present in fried foods like falafel. In addition, our responses are conditioned by experience. You know that you like falafel; you’ve been to this restaurant before and have enjoyed it. (Conversely, if you got sick last week after eating a falafel, it’s almost certain that its odors and the sight of it would not induce desire, even if you were hungry.)

Figure 4.5Pleasure graphs for eating and sex reveal some common features. This figure is adapted and extended from J. R. Georgiadis, M. L. Kringelbach, and J. G. Pfaus, “Sex for fun: a synthesis of human and animal neurobiology,” Nature Reviews Urology 9 (2012): 486–98, with permission of Nature Publishing Group.

Next is the liking phase, when pleasure peaks. That first bite gives a surge of pleasure, and each subsequent bite, somewhat less. In part this is because you are habituating to the smell, taste, and mouthfeel sensations of the food. The first bite is rather novel; subsequent bites become increasingly familiar. Somewhat later you begin responding to a mixture of conscious and subconscious signals from your body telling you that your stomach is distended and the nutrient levels in your blood have increased. This leads to the satiety phase, in which you’re less likely to eat more falafel, but you might be persuaded by something new, like a cup of fruity sorbet.

I’ve gone off on this food tangent to make a point—namely, that sexual activity is not a singular form of human experience. While it has certain unique aspects, in many ways it’s not that different from other pleasures, like eating. Let’s imagine a similar narrative concerning sex. Here I’ve chosen an example involving two women, but the particular actors involved don’t matter that much. Let’s imagine that you’re about to ovulate, and are thus at the time of the month when sexual desire runs highest. You’re feeling energetic and playful, lying on the sofa reading the newspaper. Your sweetheart comes through the door. She looks great, vibrant and slightly flushed from exercise. She comes over for a kiss, and you can smell her body and her hair and feel her soft lips brush your own. You begin to feel aroused as you realize that she is receptive. Your vagina starts to lubricate, your muscle tone softens, and you continue to kiss and caress. Clothes come off, and you can see her body. Then things really begin: kissing, stroking, licking in lots of places, with particular attention to the genital and perigenital regions. There’s a slow buildup of tension, an inevitable feeling of progression, and then orgasm, sometimes one, sometimes many. When you’re done, lingering in the afterglow, you’re less likely to initiate sex again immediately, unless something unusual happens—like your sweetie suggests some sexual activity that you’ve always wanted to try but have never done.

The pleasure graph for this experience is shown in figure 4.5 below the falafel graph, and it’s evident that there are many similarities. In both cases an internal state (hunger, a sexually receptive time in the ovarian cycle) primes you to respond to appealing sights, smells, and sounds. In both cases your mounting desire in the wanting phase is mediated by both hardwired responses and your own past experience. (You may be remembering a previous pleasurable sexual encounter.) And that increasing desire is accompanied by changes in your body that you can’t control (salivation, vaginal lubrication).

In the liking phase we begin to see some divergence in the pleasure graphs. Typically, the first bite of food gives you the most pleasure, while the first sexual touch does not. Most often there’s a buildup to orgasm, and it’s orgasm itself that is the most pleasurable moment of sex. And there’s more individual variation in sexual liking: You might reach orgasm quickly, while others achieve it slowly or not at all. 15You might typically have one orgasm in a sexual encounter, while others have many. As we have discussed, the variation in preferred sexual behaviors is huge and, of course, is not limited to the details of touching. And, of course, both eating and sex tend to produce satiety, which can be overcome by particular circumstance, most notably novelty. 16