Like food, sex is an important part of our lives. From an evolutionary perspective, the reason is obvious—the perpetuation of the species.
Sexual behavior in humans, however, involves much more than reproduction. This section provides an overview of research that has been conducted on human sexual behavior and motivation. This section will close with a discussion of issues related to gender and sexual orientation.
05. Human sexual activity, any activity—solitary, between two persons, or in a group—that induces sexual arousal. There are two major determinants of human sexual activity: the inherited sexual response patterns that have evolved as a means of ensuring reproduction and that are a part of each individual’s genetic inheritance,
and the degree of restraint or other types of influence exerted on individuals by society in the expression of their sexuality. The objective here is to describe and explain both sets of factors and their interaction.
- Types Of Activity
Human sexual activity may conveniently be classified according to the number and gender of the participants. There is a solitary activity involving only one individual, and there is a sociosexual activity involving more than one person.
Sociosexual activity is generally divided into heterosexual activity (male with female) and homosexual activity (male with male or female with female). If three or more individuals are involved it is, of course, possible to have heterosexual and homosexual activity simultaneously.
04. Solitary activity
Self-masturbation is self-stimulation with the intention of causing sexual arousal and, generally, orgasm (sexual climax). Most
masturbation is done in private as an end in itself but is sometimes practiced to facilitate a sociosexual relationship.
Masturbation, generally beginning at or before puberty, is very common among males, particularly young males, but becomes less frequent or is abandoned when sociosexual activity is available. Consequently, masturbation is most frequent among the unmarried. Fewer females masturbate; in the
In the United States, roughly one-half to two-thirds has done so, as compared to nine out of ten males. Females also tend to reduce or discontinue masturbation when they develop sociosexual relationships. There is great individual variation in frequency so that it is impractical to try to define what range could be considered “normal.”
03. Sociosexual activity
By far the greatest amount of sociosexual activity is a heterosexual activity between only one male and one female. Heterosexual activity frequently begins in childhood, and, while much of it may be motivated by curiosity, such as showing or examining genitalia, many children engage in sex play because it is pleasurable.
The sexual impulse and responsiveness are present in varying degrees in most children and latent in the remainder. With adolescence, sex play is superseded by dating, which is socially encouraged, and dating almost inevitably involves some physical contact resulting in sexual arousal. This contact, labeled necking or petting, is a part of the learning process and ultimately of courtship and the selection of a marriage partner.
02. Genetic and hormonal factors
While all normal individuals are born with the neurophysiology necessary for the sexual-response cycle described above, inheritance determines the intensity of their responses and their basic “sex drive.”
There is great variation in this regard: some persons have the need for frequent sexual expressions; others require very little; and some persons respond quickly and violently, while others are slower and milder in their reactions. While the genetic basis of these differences is unknown and while such variations are obscured by conditioning, there is no doubt that sexual capacities, like all other physiological capacities, are genetically determined.
It is unlikely, however, that genes control the sexual orientation of normal humans in the sense of individuals being predestined to become homosexual or heterosexual. Some severe genetic abnormality can, of course, profoundly affect intelligence, sexual capacity, and physical appearance and hence the entire sexual life.
The sexual response follows a pattern of sequential stages or phases when sexual activity is continued.
First, there is the excitement phase marked by an increase in pulse and blood pressure, an increase in blood supply to the surface of the body resulting in increased skin temperature, flushing, and swelling of all distensible body parts (particularly noticeable in the penis and female breasts), more rapid breathing, the secretion of genital fluids, vaginal expansion, and a general increase in muscle tension.
These symptoms of arousal eventually increase to a near maximal physiological level, the plateau phase, which is generally of brief duration. If the stimulation is continued, orgasm usually occurs.
Orgasm is marked by a feeling of sudden intense pleasure, an abrupt increase in pulse rate and blood pressure, and spasms of the pelvic muscles causing vaginal contractions in the female and ejaculation by the male. Involuntary vocalization may also occur. Orgasm lasts for a few seconds (normally not over ten), after which the individual enters the resolution phase, the return to a normal or subnormal physiological state.