Chapter 11
Physical & Cognitive Development
in Adolescence
TEENAGERS (ages 13 and 19/26)
• The physical changes that occur that involve
sexual maturity. Begin approximately 10/11 and
ends late teens/early 20’s
• The testes and ovaries enlarge. Secondary sexual
characteristics emerge.
• Adrenarche (6-9)- maturing of the adrenal glands,
then a few years later, gonadarche- maturing of
the sex organs and appearance of obvious pubital
• Androgens: DHEA- growth hormone (body hair,
faster body growth, oilier skin. Age 10, 10 times
more DHEA- at this age, boys/girls recall first
sexual attraction
Girls: ovaries produce estrogen, stimulates growth
of female genitals and development of breasts.
Principle sign of sexual maturity in girls is
menarche, the first menstruation (average age 1016).
Boys: testes increase production of androgens,
particularly testosterone, which stimulates
development of the male genitals, muscle mass,
and body hair. Principle sign of sexual maturity is
production of sperm, and first ejaculation
(spermarche); average age 13, usually nocturnal
emission (involuntary ejaculation while sleeping)
Puberty begins: boys: typically 10/11, but some
changes begin 9 and 16. girls begin at age 9/10,
but for some, age 6 or as late as 13/14.
See Table 11-1 (page 400) for body changes
Primary sex characteristics: reproduction organs
Females: ovaries, fallopian tubes, uterus, and
Males: testes, penis, scrotum, seminal vesicles,
and prostate gland
Secondary sex characteristics: physiological
signs of sexual maturation that do not
involve the sex organs. Breasts in females
and broad shoulders of males.
First sign of puberty for girls is growth of the
breasts, nipples enlarging and protrude, the
areolae (area around nipples) enlarge and
breasts form rounded shape. Some
adolescent boys have nipple enlargement
due to the distress about puberty; temporary.
Timing of puberty
Some research suggests that relationship with father
important. Girls with healthy relationships with
father tend to being puberty later; those with
parental relationships that have been cold or
distant or raised by single mother enter earlier.
Possibly pheromones, odorous chemicals given off
by males/females to attract mates (male’s sweat
and female’s urine) activates the hypothalamus
(controls sexual behavior); a natural incest
prevention mechanism; inhibits sexual attraction
for daughters.
An increase in the adolescent’s growth undergoes
a marked acceleration.
Height & weight increase dramatically, and body
proportion changes.
Typically referred to as the Growth Spurt.
The growth spurt lasts about 2 to 3 years and
beings in girls about 2 years earlier (age 10)
than boys (age 12).
This growth spurt may increase the adolescent’s
Average age that menarche begins is less than 13.
The secular trend (resulting from improved
diet, sanitation, and medical care) significantly
decreases the age at which this occurs over the
past 100 years or so.
Strenuous exercise can delay menarche by as
much as 3 to 5 years, on average.
Behind each maturational change lies the
development of essential cells within the brain
and body.
Adolescents develop at somewhat different rates.
Seeing peers develop faster may have negative
impact on a slower-developing peer.
Adults may unconsciously expect greater
maturity from a physically advanced
adolescent because of appearance which beings
to look more adult like than child like.
Emotional maturity develops more slowly than
physical maturity.
Adolescents who develop physically at an early
age may have difficulty living up to the new
demands made upon them. This can result in
disappointment, doubt, and insecurity.
• Among boys, early maturation can have
• An appearance of being more mature (facial hair,
deep voice, secondary sexual characteristics) may
enhance his status among peers.
• Early maturation can also enhance athletic
ability, which also increases status among peers,
members of the opposite sex, and adults.
• Late maturity among boys can be stressful: may
be teased, ridiculed, by more physically mature
• May fear they may never develop, which can lead
to negative self-image that can continue even
after physical maturity has finally been attained.
• Tend to find early maturation more stressful.
• Suddenly finding herself more attractive to older
males, she often lacks the emotional maturity to
deal with the situations that may result.
• Also given increased status among peers for early
development; but again, increased status is
markedly less than that enjoyed by boys who
mature early.
• May be due to the greater emphasis given to boys
to athletic ability. If girl is athletic, she may enjoy
greater peer status and less stress about it.
• Girls who mature late may share same
problems as the boys. May fear they will
remain flat chested or that boys won’t like
them, and if boys don’t like them they may
be left out of activities considered
important by peers.
• Such physically immature girls tend to be
less socially mature on personality tests.
• Girls who mature late may have an
advantage, generally becoming taller and
slimmer as adults than those who mature
The Adolescent Brain
• Dramatic changes in brains structures: emotions,
judgment, organization of behavior, and selfcontrol. Emotional outbursts occur during this
• The growth of the gray matter- neurons, axons,
dendrites begin, primarily in frontal lobes. This
impacts planning, reasoning, judgment, emotional
regulation, and impulse control
• Unused connections are pruned; others
• Between 6-13, connections between temporal and
parietal lobes strengthen (sensory functions,
language, spatial understanding). White matter
drops off as the critical period for learning ends.
Frontal lobes last to mature.
Two Major Brain Changes
• Growth Spurt
– Chiefly in frontal lobes
– Reasoning, judgment, and impulse
• Gray Matter Growth
– Continued myelination
– Facilitates maturation of cognitive
Processing of Emotions
Early teens (11-13) tend to use the amygdala, (deep in
temporal lobe- involved with emotional and
instinctual reactions). This allows emotion to override
reason (risk taking behavior).
Older teens use frontal lobe (like adults)- permitting
accurate and reasoned judgments.
Physical Activity & Mental Health
Social economic status, poverty, and chronic stress can
directly impact development.
Physical activity
Impacts both physical and mental health
Improves endurance and strength, build healthy bones,
control weight, reduces anxiety and stress, increases
self-confidence and well-being.
Sleep needs
Important to get necessary sleep- approximately 8-10
Malnourished adolescents may suffer from delayed
puberty and poor physical growth.
They are more prone to consume inordinate amounts of
carbohydrates or junk food and to engage in fad diets.
• Results when the number of calories ingested is
greater than the number used by the body. It is to a
large extent determined by inheritance.
• May inherit different numbers of fat cells, and the
number they inherit determines, in part, how well
their bodies will store fat.
• May have faulty regulation of metabolism (genetics
versus willpower); inability to recognize body cues of
hunger or satiation, development of large number of
fat cells.
• Children with over weight parents or obesity in their
families may be better able to store excessive fat than
other children.
During adolescence, obesity can present severe
• Preoccupation with self- image
• Social isolation
• Social isolation may be self-imposed out of fear of
• Teased about their weight
• May eat more to comfort, which continues the cycle.
• Functional limitations (not attending school,
household chores)
• Not exercising
• Decreased personal care
• Medical problems (diabetes, heart disease, high BP)
Body Image & Eating Disorders
Body image- how one believes they look (middle
childhood, intensifies in teens)
Anorexia Nervosa
• Overly concerned with being fat.
• Overly concerned with body image
• Continues to believe that they are too fat
• Often “good students”, model children
• Genetic: gene that leads to decreased feeding signals
(crucial chemical missing, disturbance of
hypothalamus, or high levels of opiate like substances
in spinal fluid)
• Some view it as fear of growing-up, fear of sexuality,
reaction to dysfunctional family
• Both deliberate and nonvolitional
• Characterized by progressive and/or significant
weight loss, alternate binge eating and dieting with
avoidance of any fattening foods, amenorrhea,
hyperactivity and compulsive exercising patterns, and
preoccupation with food and nutrition.
• They will typically eat great amount of food to satisfy
their hunger. Then they induce vomiting to address
their fear of gaining weight. In severe cases, death
from starvation occurs.
• Binge eating and inappropriate compensatory
methods to prevent weight gain.
• Binge: eating in a discrete amount of time an
inordinate/excessive amount of food (usually sweets).
• May use vomiting, laxatives, fasting, exercise,
• Overwhelmed with shame, self-contempt, depression,
over eating habits and body.
• Possibly related to decreased levels of serotonin,
related to depression, phobias, panic disorder.
• Some have both anorexia and bulimia.
Drug Use & Abuse
Substance abuse: harmful use of alcohol or drugs ;
continues to use despite consequences or while
engaged in hazardous activity.
Substance dependence: addiction; physiological,
psychological, or both.
• Drug use and abuse is very prevalent with
• Between 1992-1997, the number of high school
seniors who smoked jumped from 17-25%
• Approximately 9% of 8th graders and 16% of 10th
graders reported smoking on a daily basis.
• Approximately 15% of 8th graders; 31% of 10th
graders; 38% 12th graders reported using illicit drugs.
• Between 1992-1998: high school seniors who smoked
marijuana rose from 12-23%
• 17% of high school students have tried amphetamines
and 14% hallucinogens, and 10% cocaine (2000)
• 2004: 37% of 8th graders; 58% of 10th graders; and
71% of 12th graders- using alcohol
• 2004: 12% of 8th graders; 28% of 10th graders; and
34% of 12th graders- using marijuana
• Drugs/alcohol provide an element of excitement and
• Some peer groups require this in order to fit
in/finding acceptance by the group.
• This is demonstrated by a comprehensive knowledge
of street drugs and their effects or by using drugs.
• Selling drugs is a quick way to be admired and to
make money.
• Tobacco, marijuana, alcohol, heroine, crack, cocaine,
• If parents and older siblings did NOT smoke,
significantly less chance the adolescent will do so.
• If their friends smoke, more likely to smoke.
• One of the most predictor of continued smoking by
teens was their own statement that they believed they
would still be smoking in five years.
Risk factors for drug abuse
• Difficult temperament
• Poor impulse control/sensation seeking (biological or
• Family influences
• Early/persistent problem behaviors, especially
• Academic failure/lacks commitment to education
• Peer rejection
• Peer association with drugs
• Alienation and rebelliousness
• Positive attitudes about drugs
• Early initiation into drug use
The earlier they begin, more likely to persist. One
drug usually leads to more experimentation.
• Potent, major effects on physical, emotional, social
• Teens (approximately before age 15) are 5 times more
likely to development problems with alcohol than
those beginning use at age 21.
• Immediate and long-term effects on memory;
physical complications;
It is highly addictive; tends to lead to other drug
Engage in more risky behavior when using
Early use of alcohol and marijuana associated
with multiple risk taking behavior
• difficulty or inability to concentrate
• feelings of hopelessness
• weight disturbances
• sleep disturbances
• inactivity or overactivity
• lack of motivation
• low energy or fatigue
• inability to have fun
• thoughts of death or suicide
About 25% of adolescents experience
About 4% severely depressed
Adolescent and early maturing girls, and
adult women, more prone to depression
than males. Possibly related to biological
changes in puberty; the way girls are
socialized; or due to greater vulnerability to
stress in social relationships.
Risk factors:
• Female gender
• Anxiety
• Fear of social contact
• Stressful life events
• Chronic illnesses
• Parent-child conflict
• Abuse or neglect
• Parental history of depression
• Body image/eating disturbance
Deaths from motor vehicle accidents/firearms
• Leading cause of teens: car accidents; 2/5 deaths
in adolescence
• Collision greatest for 16-19 year olds
• Those who recently began driving
• Tend to drive more recklessly
• 29% (ages15-20)- drinking
• 77%- not wearing seat belts
• Firearms: 1/3 of all injury deaths/85% of all
homicides for ages 15-19.
• 43% of guns in the home more likely to kill family
member/acquaintance than self-defense
Suicide is one of the leading causes of death
among adolescents. Suicide rates for 15 – 24
year olds has significantly risen. Ages 15-19third leading cause of death
• 25% of female adolescents and 14% of male
adolescents in grades 9-12 had seriously considered
attempting suicide
• 65% of college students experienced suicidal ideation
and a plan at some point in their lives.
• 25% of adolescents indicated that if they were to
commit suicide, they would do so with an automobile
(1975); an interesting finding considering the number
of adolescents who are killed in automobile accidents;
perhaps many accidents are really suicide attempts.
• Females are more likely to attempt suicide than
males, but males are 3 times more likely to actually
kill themselves. Males use more lethal methods;
women use less violent methods and as a result are
more likely to be rescued.
• Suicide is the act of causing one’s own death. Suicide
may be active or passive and it may the direct or
indirect. Suicide is an active act when one takes one’s
own life.
• Suicide is a passive act when one does not do what is
necessary to escape death such as leaving a burning
• Suicide is direct when one has the intention of
causing one’s own death, whether as an end to be
attained or as a means to another end. E.g., when a
person kills themselves to escape or avoid
condemnation, disgrace, ruin, prison.
• Suicide is indirect (not usually called suicide)
when one does not desire it as an end or a
means, but when one nevertheless commits an
act which courts death (e.g., tending to
someone with a contagious, deadly disease and
not caring or taking safeguards to prevent
Self-Injurious Behavior
• This is often referred to as “deliberate self-harm”,
“self-mutilation”, or “cutting”. Self-injurious
behavior typically refers to a variety of behaviors in
which an individual purposefully inflicts harm to
their body for purposes not socially recognized or
sanctioned and without suicidal intent.
• Self-injurious behavior can include intentional
carving or cutting of the skin, scratching, burning,
ripping or pulling skin or hair, swallowing toxic
substances or objects, and breaking bones.
Self-Injurious Behavior
• A person who truly attempts suicide seeks to
end all feelings and suffering. A person who
self-mutilates seeks to feel better, experience
feelings, or to vent.
• Foreign body ingestions are usually
manipulative in nature. These are rarely
compulsive, impulsive, or factious in nature.
Warning Signs of Potential Suicide by
Failure to achieve in school (a sign that should
be especially heeded in students who have
superior or better-than-average ability).
Missing school for long periods of time.
Only about 11% of adolescents who committed
suicide because of perceived school failure
were actually in academic difficulty.
Warning Signs of Potential Suicide by Adolescents
• History of substance abuse, conduct problems, or
affective disorders.
• Poor coping skills and deficits in interpersonal
• Emotional illnesses
• Victim/perpetrator of violence
• Depression
• Poor impulse control
• Withdrawal from social relationships. They often feel
unwanted by their families or parents. Rejection by
teachers and peers can also contribute to social
Warning Signs of Potential Suicide by Adolescents
• Family turmoil and instability or abuse.
• History of sexual abuse.
• A humiliating or shameful event (e.g., arrest, breakup of romantic relationship, or school or work
• Termination or failure of a sexual relationship. Many
adolescents fearful of venturing in to sexual
relationships become overly attached to the one
boyfriend/girlfriend with whom they feel
comfortable. This may be a much less significant risk
factor than once thought.
Warning Signs of Potential Suicide by Adolescents
• Academic or school problems
• Access to firearms or other lethal weapons.
• Exposure to suicidal behavior.
• Previous attempts
• Feelings of being a failure, depressed, or
preoccupation with death.
• Any attempted suicide, regardless of how mild or
jokes about suicide, must be taken serious. Almost
every adolescent who committed suicide gave an
indication at one time or another that suicide was on
their mind.
Protective factors
• Sense of connectedness with family and school
and peers
• Emotional well-being
• Academic achievement
Cognitive development
Piaget- Formal-Operational Stage (11+ years)
(The reflective child):
Children develop abstract systems of thought
that allow them to use prepositional logic,
scientific reasoning, and proportional
Hypothetical & Deductive Reasoning
• Hypothetical problems can be solved, complex
deductions made, and advanced hypothesis testing
becomes possible. Acquire ability to make complex
deductions, analyze ways of reasoning, and solve
problems by systematically testing hypothetical
• Can analyze the validity of different ways of
reasoning (the foundation of science). Can develop
experiments to test hypothesis. Reflective thinking.
• How this occurs: combination of brain maturity and
expanding environmental opportunities; require
appropriate stimulation.
• Problem solving skills
• Developing a hypothesis and an experiment to
test it
• Imagining relationships systematically
• Piaget attributed acquiring this new skill to:
– Brain maturation
– Expanding environmental opportunities
Criticisms of Piaget
• Some children display this stage of thinking
well before adolescence
• May have overestimated some older
children’s abilities
• 1/3 to ½ of late teens/adults cannot think
this way
• Ignored individual differences
6 characteristics of immaturity of thinking
• idealism and criticalness- hypocrisy irritates; believe
know better than adults
• argumentativeness- to build a case
• indecisiveness- lack effective problem solving/choose
between options
• apparent hypocrisy- do not understand concept of
ideals and living up to them
• self-consciousness- assume everyone else’s views are
similar to their own; imaginary audience: observer
who only exists in the teen’s mind
• specialness and invulnerability- personal fable:
belief they are special, their experience is unique
Changes in information processing
Structural changes: changes in information
processing capacity and increasing amount of
knowledge stored in long-term memory
Declarative knowledge: factual knowledge has
Procedural knowledge- consists of skills, rules
Conceptual knowledge- understanding of
Functional change
Processes for obtaining, handling, retaining
information for functional aspects of
cognition: learning, remembering,
reasoning, decision making, mathematical,
spatial, and scientific reasoning
More proficient in drawing conclusions,
explaining their reasoning, testing
Language development
16-18 year olds- know approximately 80,000
can define abstractions and abstract words
social perspective taking: understand
another’s point of view
Moral Reasoning
Kohlberg (Table 11-3 (page 423)
Level 1- preconventional morality (ages 4-10)
people act under external controls; follow
rules to avoid punishment or to gain
stage 1: orientation towards punishment
and obedience
stage 2: instrumental purpose & exchange
(conform for self-interest)
Moral Reasoning
Kohlberg (Table 11-3 (page 423)
Level 2- conventional morality (ages 11-adult)
Internalize standards of authority figures; concerned
about pleasing others; many never move beyond
this stage
Stage 3: maintaining mutual relations, approval of
others/golden rule (want to please)
Stage 4: social concern and conscience (ding duty,
respect for authority, maintain social order;
always wrong if violates a rule or harms someone)
Moral Reasoning
Kohlberg (Table 11-3 (page 423)
Level 3- postconventional morality (early adolescence,
young adulthood, if ever)
Recognize conflicts between moral standards and
make own judgment on principles of right/wrong,
fairness, justice.
Stage 5: morality of contract, individual rights,
democracy of accepted law (rational, value will of
majority, welfare of society)
Stage 6: morality of universal ethical principles (do
what think is right, regardless of legal restrictions
or opinions of others; use internalized standards)
Criticism of Piaget
• Some development levels much younger
• Lack of relationship between moral
reasoning and moral behavior
• Do not necessarily act more moral even if
achieved higher stage
Neither Kohlberg or Piaget considered role of
parent in moral development
• Parents contributions to cognitive and
emotional realms ignored
• Parents who use humor and praise, listened
to their children, asked their opinions,
clarified questions, reworded answers, made
sure children understood the issues, had
children with higher reasoning abilities and
utilized scaffolding
Gender differences
Girls tend to score higher than boys on moral
judgments and emphasized care-related
concerns more.
Kohlberg’s theory overall may be culturally
Influences on Motivation and Achievement
Believe they can master and regulate own learning
Must build child’s self-efficacy
Parenting Styles, Ethnicity and Peer Influence
Authoritative parenting is best even in adolescence.
Authoritarian parenting: punish and fail to discuss
Permissive parenting: indifferent to grades, no rules
about tv, do not help with homework, neglectful
Learned helplessness occurs when parents not
involved in supportive way; self-fulfilling
prophecy. Easier to associate poor grades
with lower ability than to other
circumstances without parental
The Educational System
• Quality makes a difference
• Orderly
• Unopposed atmosphere
• Active, energetic principle
• Teachers making decisions
• High expectations for students
• Emphasize academics versus extracurriculum
• Closely monitored student performance
Dropping out
• 5% of high school students dropped out
• 11% of 16-24 year olds in 2001 dropped out
• higher among boys; higher with minorities
• active engagement: helps keep kids in school
• support student for any career, accept when not
college bound

Chapter 11 -