EARLY ADOLESCENCE: SURVEY DATA ON SEXUAL BEHAVIOR

The term “sexual behavior” covers a great variety of distinct behavioral variables, including covert behavior such as sexual dreams and fantasies; measures of psychophysiological arousal such as acid phosphatase excretion; autosexual behavior such as self-stimulation and genital masturbation; and overt sociosexual behavior such as dating, kissing, or sexual intercourse. Animal-behavior research has provided a useful classification scheme for observable patterns of hormone-influenced sociosexual interaction: attractivity, proceptive behavior, and receptive behavior. Attractivity denotes those aspects of the sexually mature individual—in lower mammals mainly odor cues, in nonhuman primates both odor and visual cues— which elicit the sexual approach or proceptive behavior of a potential mating partner. Receptive behavior is a term used for postural compliance with a partner who initiates the copulatory sequence. Although originally defined for female mammals, these terms seem applicable to male mammals as well. It is fairly easy to point out analogous patterns of sociosexual interaction for humans. Any human study, however, also has to take into consideration covert and autosexual behavior, since they constitute major aspects of human sexual behavior.

To what extent the various aspects of sexual behavior are intercorrelated in development and influenced by somatic-endocrine factors has not been sufficiently investigated. Heterosexual attractivity seems to be brought about primarily by the development of the secondary sex characteristics in puberty. Evidence for this conclusion comes from ample but undocumented sex-clinical experience, from systematic rating studies of sexual attractivity and from studies of men’s arousal response, measured by penile plethysmography, to pictures or films of nude females of varying degrees of sexual maturation (Freund and others, although longitudinal studies of attractivity changes in early adolescence have not been done. Flirting, dating, and related proceptive behaviors also are of major importance in adolescence and play only a minor role in childhood.

Particularly detailed data are available on genital sexuality. The reports by Kinsey and others have documented that many aspects of sexual behavior, including orgasm, can occur well before puberty, but sexual activity in childhood usually is only sporadic and lacks the regularity of adolescent and adult life (for a summary of the Kinsey data on childhood, see Meyer-Bahlburg). It is in most cases not before puberty that sexual concerns and behavior in its various aspects become a major part of everyday life.

Using orgasm as the behavioral criterion, Kinsey and others demonstrated striking differences between the sexes during puberty. Boys showed a sudden upsurge in sexual activity which could begin a year or more before the onset of puberty was noticeable; they usually reached their life peak in terms of orgasmic frequency within a year or two after the onset of puberty. Most of this early activity was masturbation. For two-thirds (68%) of the boys in the Kinsey sample, masturbation provided the first ejaculation; for the remaining ones, nocturnal emissions and heterosexual coitus provided the first ejaculation. By age fifteen, 82% of the boys were experienced in masturbation to orgasm.

In girls, by contrast, the gradual and steady increase in the accumulative incidence of erotic arousal and orgasmic response which was observed before puberty continued into puberty and beyond; typically, women did not reach their maximum rate of orgasm until their middle twenties to thirties. Of the relatively small percentage of girls in the Kinsey sample who experienced orgasm during puberty (20% by age fifteen), the majority (84%) used masturbation as the most important outlet. For the average male, adolescence was the age of highest orgasmic frequency, with 3.4 outlets per week, whereas the corresponding figure for sexually active females (including masturbation) was around 0.5 orgasms per week.

The occurrence of the first ejaculation—Levin introduced the appropriate term thorarche (from Greek thor?s, sperm, and arch?, beginning)—is brought about by masturbation in the majority of North American males. Asayama has demonstrated the same for Japanese males. Thus, there appears to be a relatively close relationship of puberty, thorarche, and autosexual activity for most males, while masturbation to orgasm by females is a relatively late event. In both Kinsey and others’ and Asayama’s reports, masturbation was practiced by only a minority of female adolescents; it developed later than the somatic markers of puberty in the majority of those who ever practiced it.