Human sexual response cycle

The human sexual response cycle is a four-phase model of physical and emotional responses that occur when a person engages in sexual activity. The four stages of the sexual response cycle are excitement, plateau, orgasm, and resolution. Both men and women experience each of these sensations, and either a partner or oneself can stimulate the response. When partnered sexual activity is at play, each partner does not always experience the phases of the cycle at the same time. The intensity and duration of each sensation also varies from person to person. First proposed in the 1966 book Human Sexual Response by research team William H. Masters and Virginia E. Johnson, the model has since been used by many professionals to describe the mechanisms that lead to human sexual arousal. Experts also utilize the cycle to understand the body's response to sexual stimulation in an effort to advance the psychological study of sexual arousal in humans. However, others have proposed alternate models in response to criticisms of the basic four-phase sequence.

Background

The human sexual response cycle was first outlined by the Masters and Johnson human sexuality research team, which consisted of gynecologist William H. Masters and his assistant, Virginia E. Johnson. The model was also influenced by the studies of sexologistAlfred Kinsey, who sought to understand the biological influences behind sexual responses. Masters and Johnson wanted to understand sexual function beyond the biological factors and began studying the psychological sources of human sexual response. Although the team primarily sought to specify physiological-based measurements of human sexual response, they were not afraid to ask questions such as "In what circumstances do people find sexual satisfaction?" This approach used psychoanalytical principles to understand the inner sexual experience. The researchers hoped a better understanding of a person's psychological makeup would help explain why some people experienced difficulties manifesting physical responses to sexual arousal.

Masters and Johnson spent years personally observing thousands of people's orgasms as they were subjected to varying forms of sexual stimuli. Approximately 10,000 orgasms were observed during this study in an effort to formulate a standardized sexual response cycle. Masters and Johnson's final model was first discussed in their 1966 publication of Human Sexual Response. The model separated the process into four stages: excitement, plateau, orgasm, and resolution. Although three-quarters of its study's subjects were women, the team's model stressed the similarity of both genders' responses to sexual arousal. Masters and Johnson studied self-gratifying activities such as masturbation as well as sexual intercourse between both heterosexual and homosexual couples. The team even built a penis-shaped camera that could be used to photograph the physiological changes that occurred in a woman's vagina during orgasm. The overall goal of the study was to dispel any misconceptions surrounding human sexuality by providing the public with comprehensive knowledge of the entire process.

The research of the Masters and Johnson team concluded that the structure of the orgasm—characterized by intense muscle tightening around the genital area that is experienced as a wave of pleasurable sensations throughout the body—was the same in men and women regardless of their sexual orientation. The anatomy of the orgasm also did not differ based on the means of stimulation. The individual sex organs completed the orgasm differently, but the systems of arousal were essentially the same and were characterized by extended muscle contraction and tension, excessive filling and enlargement of the blood vessels, and increased blood flow into the genital tissues. Masters and Johnson's model was criticized for its narrow physiological focus by a number of scholars following its introduction; nevertheless, the model continued to be used as the standard for describing the functional process of the human sexual response cycle for years to come. It was also used by researchers interested in studying various forms of sexual dysfunction in men and women, such as erectile dysfunction.

Overview

The basic human sexual response cycle has been described in four phases. The first phase is called the excitement phase, during which sexual stimulation results in a number of physical responses. This phase, which can last anywhere from a few minutes to a few hours, is characterized by several bodily reactions that include increased muscle tension, faster heartbeat and breathing, flushed skin, and increased blood flow to the genitals. For women, this phase also involves an increase in vaginal lubrication and a swelling of the breasts and vaginal wall. For men, the excitement phase swells the testicles causing the scrotum, the pouch containing the testicles, to tighten. The penis then begins expelling a lubricating liquid.

The next phase is called the plateau phase, a sensation distinguished by a person reaching the brink of orgasm. All physical reactions from the excitement phase greatly intensify during the plateau. For women, the vaginal swelling and increased blood flow turns the vaginal walls dark purple. The clitoris, the female sex organ found at the front of the vaginal opening, becomes extremely sensitive and withdraws into the clitoral hood to avoid direct stimulation. The penis performs a similar action, with the testicles retracting into the scrotum. Muscle spasms can occur in the face, feet, and hands as muscle tension continues to increase.

The third phase of the human sexual response cycle is orgasm, the shortest phase of the process. The orgasm is the climax of the cycle, producing the most intense sensation of the process. The phase produces involuntary muscle contractions and spasms while heart and breathing rates reach their highest. Men experience contractions in the muscles at the base of the penis, often causing semen to ejaculate from the penis's head. In women, the contractions occur in the muscles of the vagina and the uterus. In some cases there may be a discharge of fluid, known as female ejaculation, though there is little scientific consensus on this phenomenon. The orgasm is marked by the sudden release of sexual tension throughout the body and can produce a rash-like flush all over the skin.

The final phase of the cycle, resolution, involves the body gradually returning to a state of normal function. The swelling of muscles and tissues slowly diminishes as does any rapid breathing or heart rate. The resolution phase often results in a blissful feeling followed by a sense of exhaustion. Once the body's levels have normalized, the body can try returning to the orgasm phase. Women are often capable of returning to the orgasm phase faster than men are, and some women can achieve multiple orgasms in a small amount of time. Men typically need an extended amount of recovery time following orgasm. This recovery time is referred to as the refractory period, and men cannot orgasm again until they have fully recovered. The length of the refractory period varies among men and often increases in duration with age.

Criticisms

While a four-phase human sexual response remains the standard model, Masters and Johnson's pioneering work has received significant criticism. Most notably, various researchers have disagreed with the view that female and male sexual response follow the same stages, and especially the correlation between penile erection and vaginal lubrication in the plateau phase. Some studies have also countered specific findings such as Masters and Johnson's statement that males cannot achieve multiple orgasms or the ambiguous transition from excitement to plateau. Finally, there has been criticism of the standard model's focus on physiology rather than emotional and psychological aspects. Alternative models have often sought to incorporate a broader approach to sexual response, especially for females, including the circular model first proposed by Rosemary Basson in the early 2000s. While the circular model recognizes the role an orgasm plays in sexual pleasure, it also recognizes other sources of pleasure during sex.

Bibliography

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Harrington, Austin, et al., editors. "Sexuality."Encyclopedia of Social Theory. Routledge, 2006.

Mark, Kristen. "What We Can Learn from Sexual Response Cycles." Psychology Today, 19 Nov. 2012, www.psychologytoday.com/blog/the-power-pleasure/201211/what-we-can-learn-sexual-response-cycles. Accessed 1 Aug. 2024.

Masters, William H., and Virginia E. Johnson. Human Sexual Response. Ishi Press, 2010.

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