Psychology2016

404 CHAPTER 10

Human Sexual Behavior

I’ve heard that men and women experience sex differently—is

that true? What is different?

In 1957, gynecologist Dr. William Masters and psychologist Dr. Virginia Johnson began

what would become a controversial* study of the human sexual response in 700 men and

women volunteers (Masters & Johnson, 1966). At that time in history, human sexuality

was still a relatively forbidden topic to all but young adults, who were exploring the

concepts of “free love” and engaging in premarital sex far more openly than in the past.

Masters and Johnson devised equipment that would measure the physical responses that

occur during sexual activity. They used this equipment to measure physiological activity

in both men and women volunteers who either were engaging in actual intercourse or

masturbation. Although many conservative and religious people were outraged by this

research, it remains one of the most important studies of the human sexual response.

Sexual Response

10.6 Identify the four stages of a sexual-response cycle.

Masters and Johnson (1966) identified four stages of a sexual-response cycle in their

groundbreaking research. Although these stages are similar in both men and women,

there are some differences. Also, the transition between the stages is not necessarily as

well defined as the descriptions of the stages might seem to describe, and the length of

time spent in any one phase can vary from experience to experience and person to person.

PHASE 1: EXCITEMENT This first phase is the beginning of sexual arousal and can last

anywhere from 1 minute to several hours. Pulse rate increases, blood pressure rises,

breathing quickens, and the skin may show a rosy flush, especially on the chest or

breast areas. In women, the clitoris swells, the lips of the vagina open, and the inside of

the vagina moistens in preparation for intercourse. In men, the penis becomes erect, the

testes pull up, and the skin of the scrotum tightens. Nipples will harden and become

more erect in both sexes, but especially in the female.

PHASE 2: PLATEAU In the second phase of the sexual response, the physical changes

that began in the first phase are continued. In women, the outer part of the vagina

swells with increased amounts of blood to that area, while the clitoris retracts under

the clitoral hood but remains highly sensitive. The outer lips of the vagina become red-

der in color. In men, the penis becomes more erect and may release a few drops of fluid.

This phase may last only a few seconds to several minutes.

PHASE 3: ORGASM The third phase is the shortest of the three stages and involves a series

of rhythmic muscular contractions known as the orgasm. In women, this involves the mus-

cles of the vaginal walls and can happen multiple times, lasting slightly longer than the

orgasm experience of the male. The uterus also contracts, creating a pleasurable sensation.

In men, the orgasmic contractions of the muscles in and around the penis trigger the release

of semen, the fluid that contains the male sex cells, or sperm. Men typically have only one

intense orgasm. Timing is also different for women and men, with women taking longer to

reach orgasm than men and women requiring more stimulation to achieve orgasm.

PHASE 4: RESOLUTION The final phase of the sexual response is resolution, the return

of the body to its normal state before arousal began. The blood that congested the blood

vessels in the various areas of the genitals recedes; the heart rate, blood pressure, and

orgasm
a series of rhythmic contractions of
the muscles of the vaginal walls or
the penis, also the third and shortest
phase of sexual response.

semen
fluid released from the penis at
orgasm that contains the sperm.

resolution
the final phase of the sexual response
in which the Dody is returned to a nor-
mal state. *controversial: leading to arguments or opposing viewpoints.