Page 127 - Berkshire Encyclopedia Of World History Vol I - Abraham to Coal

12 berkshire encyclopedia of world history

Snow and adolescence are the only problems that disappear
if you ignore them long enough. • Earl Wilson
(twentieth century)

Historical Variations in keeping up with biological reality. If young people who
the Timing of Puberty are physically, sexually, and psychologically precocious in
The major physical and psychological changes associated comparison with the same age cohort of just a generation
with puberty occur during the second decade of human ago are treated as if they were children, both the young
life regardless of historical time or place. However, within people and the society will experience disruptions.
these temporal boundaries, the environment in which a The secular trend has another far-reaching effect on the
child is raised can affect the details of the onset and tim- adolescent and the community. Hormonal and brain
ing of puberty.Thus, since about 130 years ago, the age changes associated with puberty account for some, but
of onset of puberty has been decreasing by approximately not all, of the maturation of a person during and after the
four months each decade in some western European teen years. Cognitive skills such as the ability to plan, to
nations. This trend also began to appear in other coun- control impulses, and to appreciate the long-term conse-
tries across the world about fifty years ago.The decline in quences of one’s actions also become more sophisticated
the age of onset of puberty through recent historical time, with age but develop independently of the hormonal and
known as the “secular trend,” has been accompanied by brain changes associated with puberty per se.Thus, a dis-
a more rapid pace of pubertal change. Age of menarche sociation exists between the maturation of physiological
and attainment of adult status reflect this pattern. Thus, and motivational changes associated with puberty and
in urban populations, where the secular trend is most evi- the development of cognitive skills that allows for
dent, menarche occurs on average at the age of twelve, thoughtful, disciplined, forward-looking planning.Accel-
whereas in Papua New Guinea, where the secular trend eration of puberty does not lead to earlier maturation of
is not in evidence, menarche does not occur until a girl cognitive skills, which, therefore, lag further and further
is eighteen years old.The secular trend affects growth pat- behind with the earlier and earlier onset and faster and
terns in a similar way. In the United States, where the age faster rate of puberty. Before the secular trend, the ten-
of onset of puberty has been decreasing steadily for dency of sexually mature adolescents to act on impulse,
decades, girls reach their adult height at an average of 13 take risks, break rules, and seek novelty was more likely
years of age, whereas U.S. boys reach their adult height to be offset by an increasing capacity to think clearly
at an average of 15.5 years. By contrast, among the about the meaning and consequences of their actions.
Kikuyu people of eastern Africa, where puberty begins With the appearance of the secular trend, adolescents are
later, girls attain their adult height during their late teens able and willing to behave in ways that can have harm-
on average and boys during their early twenties. Differ- ful, even tragic, consequences but do not always have the
ences in the age of onset and duration of puberty coin- cognitive resources to inhibit such behavior. Historically,
cide with differences in the standard of living of a we seem to be witnessing a growing disconnect between
population. In particular, decreases in a child’s level of what actions adolescents want to take and can take and
exposure to disease, increased quality of nutrition, and how adolescents reason about those actions.
improved health of the mother during pregnancy seem to
Gwen J. Broude
be causes of the secular trend.
The secular trend has important implications for the See also Childhood; Initiation and Rites of Passage
adolescent experience for a number of reasons. Obvi-
ously earlier onset of puberty will mean earlier expression
of the psychological and behavioral traits associated Further Reading
with adolescence. Less obviously, when onset of puberty Aries, P. (1962). Centuries of childhood. New York: Vintage Books.
Dahl, R. (2003). Beyond raging hormones: The tinderbox in the teenage
is accelerated as rapidly as it is by the secular trend, a soci-
brain. Cerebrum, 5(3), 7–22.
ety’s expectations about its young people may not be Hall, G. S. (1904). Adolescence. New York: Appleton-Century-Crofts.