102 ChapTer 3 Development Over the Life Span
early 20s; full neurological and cognitive ma-
turity often does not occur until about age 25,
much later than commonly believed (Albert &
Steinberg, 2011).
These discoveries would help explain why
the strong emotions of the adolescent years of-
ten overwhelm rational decision making and self-
control, causing some teenagers to behave more
impulsively than adults in the heat of the mo-
ment (Casey & Caudle, 2013; Steinberg, 2007). It
would explain why adolescents are more vulner-
able to pressure from peers to try risky, dumb, or
dangerous things—why taunts of “I dare you!”
and “You’re chicken!” have more power over a
15-year-old than a 25-year-old. Even when teen-
agers know they are doing the wrong thing, many
lack the reasoning ability to foresee the conse-
quences of their actions down the line (Reyna &
Farley, 2006).
Watch the Video Special Topics: Risky Behavior
and Brain Development at MyPsychLabThe Psychology of adolescence
Lo 3.14
The media love sensational stories about teen-
agers who are angry, violent, live in emotional
turmoil, feel lonely, have low self-esteem, hate
their parents, and are running wild sexually.
Yet, in reality, most teenagers are doing pretty
well. Studies of representative samples of adoles-
cents find that only a small minority is seriously
troubled, angry, or unhappy. The rate of violent
crimes committed by adolescents has been drop-
ping steadily since 1993. Overall feelings of self-
esteem do not suddenly plummet after the age
of 13 for either sex (Gentile et al., 2009). And
according to the National Youth Risk Behavior
Survey, today’s high school students are actually
more sexually conservative than their parents
were at their age: Fewer are having sex, and
among those who are, the number of partners
has declined (Bogle, 2008; Eaton et al., 2008;
Rosin, 2012).
Nevertheless, three kinds of problems are
more common during adolescence than during
childhood or adulthood: conflict with parents,
mood swings and depression, and, as we saw,
higher rates of reckless, rule-breaking, and risky
behavior (Steinberg, 2007). Rule breaking often
occurs because teenagers are developing their own
standards and values, often by trying on the styles,
actions, and attitudes of their peers, in contrast to
those of their parents.but partly because others in their peer group
regard them as being sexually precocious, they
are also more likely to fight with their parents,
drop out of school, have a negative body image,
and be angry or depressed (Westling, Andrews,
& Peterson, 2012; Westling, 2008). Early men-
arche itself does not cause these problems;
rather, it tends to accentuate existing behav-
ioral problems and family conflicts. Girls who
go through puberty relatively late have a more
difficult time at first, but by the end of adoles-
cence, many are happier with their appearance
and are more popular than their early- maturing
classmates (Caspi & Moffitt, 1991; Stattin &
Magnusson, 1990).
When people think of physical changes in
adolescence, they usually think of hormones and
maturing bodies. But the adolescent brain under-
goes significant developmental changes, notably
a major pruning of synapses (neural connec-
tions). This pruning occurs primarily in the pre-
frontal cortex, which is responsible for impulse
control and planning, and in parts of the brain
involved in emotional processing (Spear, 2000).
Another change involves myelinization, which
provides a sheath of insulation for neurons and
improves the efficiency of neural transmission
(see Chapter 4). Myelinization strengthens the
connections between the emotional areas of the
brain and the reasoning prefrontal cortex. This
process continues through the late teens andChildren typically reach puberty at different times. These
girls are all the same age, but they differ considerably in
physical maturity.