SEXUAL FUNCTION: Understanding Why People are Addicted to Porn
While others were collecting data by way of surveys, two researchers, William Masters and Virginia Johnson (1970), were taking a different tack. They brought the study of sexual behavior into the laboratory just as one might study other aspects of behavior.
In their work, they observed and recorded at least 15,000 sexual acts. They observed sexual acts under a wide variety ofconditions: between married couples, between strangers, between couples with a variety of sexual and interpersonal problems, and under selfstimulation. A rather complete picture of the physiology of human sexual response has emerged from their observations. In addition, Masters and Johnson have spent much of their efforts discovering both the nature of sexual dysfunction and its possible treatment. As was the case with the surveys, however, these data come from a selected group of volunteer subjects who allowed themselves to be watched.
We can be quite certain that Masters and Johnson's physiological findings are general to human adults, but we cannot always be certain that either their therapeutic outcomes or the subjective reports are general to the entire population of adult men and women. Even so, the scientific study of sexual behavior has brought us much closer today to understanding the nature of sexual behavior, its physiology, and its frequency than was possible in the past.
SEXUAL FUNCTION To label an individual's sexual practice as a "dysfunction" implies that we know something about what normal sexual functioning is, or should be. In this section, we will discuss the physiology of the normal human sexual response, and then we will discuss sexual dysfunction-what it is, what causes it, and how it can be treated.
THE PHYSIOLOGY OF THE HUMAN SEXUAL RESPONSE In both men and women, the sexual response consists of three phases:
The first is erotic arousal, in which a variety ofstimuli-tactile, visual, and more subtle ones such as fantasy-produce arousal.
The second phase, physical excitement, consists of penile erection in the male and of vaginal lubrication and swelling in the genital area of the female.
The third phase is orgasm. We shall review these phases in some detail because sexual dysfunction can disrupt any of them.
In men, erotic arousal results from a wide variety of events. Being touched on the genitals or looking at and touching a sexually responsive partner are probably the most compelling stimuli. In addition, visual stimuli, smells, a seductive voice, and erotic fantasies, among many others, all produce arousal.
The second phase of excitement is intertwined with the first phase of erotic arousal. In the male, it consists of penile erection. Sexual excitement stimulates parasympathetic nerves in the spinal cord, and these nerves control the blood vessels of the penis. These vessels widen dramatically and blood streams in, producing erection. The blood is prevented from leaving by a system of valves in the veins. When these parasympathetic fibers are inhibited, the vessels empty, and rapid loss of erection occurs.
Orgasm in men consists of two stages that follow each other very rapidly -emission and ejaculation. Unlike arousal and erection, orgasm is controlled by the sympathetic nervous system, as opposed to the parasympathetic nervous system. When sufficient rhythmic pressure on the head and shaft of the penis occur, the stage of orgasmic inevitability is reached and orgasm arrives. Orgasm is engineered to deposit sperm deep into the vagina near the head of the uterus, maximizing the possibility offered stimuli.
Emission occurs when the reproductive organs all contract. This is followed very rapidly by ejaculation, in which powerful muscles at the base of the penis contract vigorously, ejecting sperm from the penis. During ejaculation, these muscles contract by reflex at intervals of 0.8 seconds. This phase of orgasm is accompanied by intense pleasure. After orgasm has occurred, a man unlike a woman, is "refractory," or unresponsive to further sexual stimulation for some interval. This interval varies from a few minutes to a few hours, and it lengthens as the man gets older.
The sexual response of a woman transforms the normally tight and dry vagina into a lubricated, perfectly fitting receptacle for the erect penis. The Erotic arousal stimuli that produce arousal in women are similar to those that produce arousal in men. Kissing and caressing, visual stimuli, and a whole host of subtle cues are usually effective as sexually arousing stimuli. In our culture, at least, there appear to be some gender differences in what is arousing, with subtle stimuli and gentle touch more initially arousing to women than direct stirnulati on.
With arousal, the excitement or "lubrication-swelling'' phase begins in the woman. When at rest, the vagina is collapsed, pale in color, and rather dry. When arousal occurs, the vagina balloons exactly enough to "glove" an erect penis, regardless of its size. At the same time, the clitoris swells and lubrication occurs on the walls of the vagina, making penile insertion easier. As excitement continues, the walls of the uterus fill with blood, and the uterus enlarges. This engorgement of blood and swelling greatly add to erotic pleasure and set the stage for orgasm.
Orgasm in women consists of a series of reflexive contractions of the muscles surrounding the vagina. These contract rhythmically at 0.8 second intervals against the engorged tissue around the vagina, producing the ecstatic sensation of orgasm. Both the clitoris, a small knob of tissue located forward of the vagina, and the vagina itself play a role: orgasm is triggered by stimulation of the clitoris, and then expressed by contraction of the vagina. Thus, the sexual response of both men and women is quite similar. Similar stimuli produce erotic arousal in both sexes. Blood flow under the control of the parasympathetic nervous system produces physical excitement, both penile erection and the lubrication and swelling phases of the vagina. Orgasm consists of powerful muscular contractions at 0.8 interval seconds, produced by rhythmic pressure on the head and shaft of the penis in the man and of the clitoris of the woman.
These parallels are lovely and deep. Before they were known, it was easy to fall prey to the belief that chasms separated the experience of sex between men and women. To learn that one's partner is probably experiencing the same kind of joys that you are is powerful and binding knowledge. ~~~~~~~~~~~~~~~~~~