Adolescence: Physical and Cognitive Development

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CHAPTER 11

• Adolescence Physical and Cognitive Development

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Puberty The Biological Eruption
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Puberty The Biological Eruption

• Puberty
• Stage of development characterized by reaching
  sexual maturity and the ability to reproduce
• Onset of adolescence coincides with advent of
  puberty
• Feedback loop
• Hypothalamus signals the pituitary gland, which
  in turn releases hormones that control physical
  growth and the gonads
• Gonads respond to pituitary hormones by
  increasing production of sex hormones
• Sex hormones further stimulate the hypothalamus,
  perpetrating the feedback loop

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Puberty The Biological Eruption (contd)

• Primary sex characteristics
• Females ovaries, vagina, uterus, and fallopian
  tubes
• Males penis, testes, prostate gland, and seminal
  vesicles
• Secondary sex characteristics
• Breast development, deepening of the male voice,
  and the appearance of facial, pubic, and underarm
  hair
• Not involved in reproduction

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The Adolescent Growth Spurt

• GIRLS
• Girls growth spurt at age 10
• Girls gain a little more than 13 inches in
  height spurt in weight continues for 2 years
  after growth spurt begins
• Hips get wider due to having twice as much body
  fat as boys
• Girls body shape more rounded

• BOYS
• Growth spurt at age 12
• Peak reached 2 years later
• Gain 14 ½ inches in height
• Eventually boys become taller and heavier than
  girls
• Boys shoulders get broader

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Fig. 11-1, p. 228
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Fig. 11-2, p. 229
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Asynchronous Growth

• Children who spurt earlier more likely to have
  longer torsos and shorter legs
• No significant differences between early and late
  sprouters in the total height at maturity
• Asynchronous growth
• Different parts of the body grow at different
  rates
• Hands and feet mature before the arms and legs do
• Legs reach peak before shoulders and chest
• Boys stop growing out of pants about a year
  before they stop growing out of their jackets

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The Secular Trend

• During the 20th century, children in the Western
  world grew more rapidly and wound up taller than
  children from earlier times.
• Accompanied by an earlier onset of puberty
• Known as a secular trend
• Occurrence of a secular trend in height and
  weight has been documented in nearly all European
  countries and the United States.
• Nutrition and medical advances contributed to
  height increase.

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Fig. 11-3, p. 230
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Changes in Boys

• Pituitary gland stimulates the testes to increase
  output of testosterone.
• Leads to further development of male genitals
• First sign of puberty is accelerated growth of
  the testes, which begins at about 11½ years old.
• Testicular growth accelerates testosterone
  production and other pubertal changes.
• Penis begins a spurt of accelerated growth about
  a year later
• Still later, pubic hair spurts
• Underarm and facial hair appears about age 15.

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Changes in Boys (contd)

• Facial hair first appears on upper lip
• Full shaving occurs in half of American boys at
  age 17
• Voice deepens at age 14 or 15 because of the
  growth of the voice box or larynx and the
  lengthening of the vocal cords.
• Testosterone triggers development of acne.
• Boys more prone to acne
• Males have erections from infancy but not
  frequent until age 13 or 14, resulting in
  nocturnal emissions.
• Wet dreams

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Changes in Boys (contd)

• Mature sperm found in ejaculatory emissions by
  age 15
• Ability to ejaculate precedes presence of mature
  sperm
• Half of all boys experience gynecomastia
  (enlargement of the breasts), which declines in a
  year or two.
• At 20 or 21, young men stop growing taller
  because testosterone causes epiphyseal closure,
  which prevents the long bones from making further
  gains in length.

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Changes in Girls

• The pituitary gland signals the ovaries to vastly
  increase estrogen production at puberty.
• Estrogen may stimulate growth of breast tissue
  beginning at age 8 or 9 (breast buds).
• Breasts reach full size in about 3 years.
• Mammary glands are not fully mature until a woman
  has a baby
• Estrogen also helps widening of pelvis and
  rounding of hips.

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Changes in Girls (contd)

• At about age 11, girls adrenal glands produce
  small amounts of androgens that contribute to
  development of underarm and pubic hair.
• Estrogen causes the labia, vagina, and uterus to
  develop during puberty.
• Androgens cause the clitoris to develop
• Vaginal lining varies in thickness according to
  the amount of estrogen in the bloodstream.
• Estrogen brakes the female growth spurt before
  the ending of the male growth spurt.

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Menarche

• Menarche
• First menstruation
• Occurs between ages 11 and 14
• Some girls as earlier as age 9 some as late as
  age 16
• Height-to-weight ratio contributes to age of
  menstrual cycle
• Average triggering weight depends on the girls
  height
• Early starting in Westernized countries has
  stabilized

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Fig. 11-4, p. 232
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Regulation of the Menstrual Cycle

• Estrogen and progesterone levels regulate the
  menstrual cycle.
• Ovulation typically begins 12 to 18 months after
  menarche.
• Most menstrual cycles begin in the first two
  years or so after menarche occurs without
  ovulation.
• If ovulating, a ripe ovum is released by the
  ovary when estrogen reaches peak blood levels.
• Average menstrual cycle is 28 days
• Menstrual cycle irregular for first few years
  after menarche but later assumes a regular pattern

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Early Versus Late Maturers

• BOYS
• Early-maturing boys tend to be more popular than
  late-maturing boys and more likely the leaders in
  their school.
• Some early-maturing boys engage in delinquency
  and aggression as well as sexual encounters they
  may not be prepared for.
• GIRLS
• Early-maturing girls tend to have lower
  self-esteem than male counterparts.
• Early-maturing girls are conspicuous with height
  and developing breasts.
• Even worse if development started in elementary
  school
• May be teased for it and may get lower grades

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Body Image

• Body image refers to how physically attractive we
  perceive ourselves to be and how we feel about
  our body.
• By age 18, girls and boys are more satisfied with
  their bodies than they were in their earlier
  teens.
• Adolescent females tend to be more preoccupied
  with body weight and slimness than adolescent
  males.
• Adolescent males may want to increase body mass.

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Health in Adolescence
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Causes of Death

• Greatest causes of adolescent death
• Accidents, mostly with motor vehicles
• Homicides
• Suicides
• Death rates twice higher for males than females
• Males take more risks
• Poor adolescents living in urban areas of high
  population at greatest risk of homicidal death
• Homicide rates greater for African-American
  adolescents than for European-American adolescents

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Fig. 11-5, p. 211
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Nutrition

• Average girl needs 1,800 to 2,400 calories per
  day average boy needs 2,200 to 3,200 calories
  per day
• At peak of spurt, adolescents use twice as much
  calcium, iron, zinc, magnesium, and nitrogen as
  during the other years of adolescence.
• Irregular eating patterns contribute to
  adolescents nutritional deficits, especially
  skipping breakfast.
• More likely to obtain less vitamin A, thiamine,
  and iron but more fat, sugar, and sodium than
  recommended

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Eating Disorders

• Due to slimming down of American ideal, girls are
  more prone to eating disorders
• Anorexia nervosa
• Life-threatening eating disorder characterized by
  extreme fear of being heavy, dramatic weight
  loss, a distorted body image, and resistance to
  eating enough to maintain a healthful weight
• Female-to-male ratio of anorexia is 10 to 1
• More affluent European-American females have body
  image issues.

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Eating Disorders (contd)

• Females with anorexia
• Drop 25 of their body weight within a year,
  resulting in abnormalities in the endocrine
  system that prevent ovulation
• General health declines
• Every system in the body is affected, including
  respiratory and cardiovascular systems
• At risk for premature development of osteoporosis
• Mortality rate is between 4 and 5
• Distortion of body image is major feature of the
  disorder
• Anorexic woman sees self in mirror as too heavy

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Bulimia Nervosa

• Bulimia nervosa
• Cyclical binge eating and purging
• May include strict dieting
• Fasting, laxatives, and demanding exercise regime
• Tends to afflict women during adolescence and
  young adulthood
• Eating disorders connected with depression
• Eating disorders run in families, indicating
  genetic involvement eating disorders tend to
  involve obsessionistic and perfectionistic
  personality traits

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Cognitive Development Piagets Stage of Formal
Operations
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Piagets Stage of Formal Operations

• Formal operations refers to the ability to
  abstract reason, classify objects, hypothesize,
  and formulate arguments.
• Top level of Piagets theory
• Adolescents have reached cognitive maturity in
  the formal operations stage.
• Formal operations can begin as early as 11 or 12
  years old.

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Hypothetical Thinking

• Adolescents develop concept of what might be
  rather than what is.
• Adolescents try on different clothes and
  attitudes to see which work best for them.
• Some may experience anxiety due to pressure to
  pick the best career fit.

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Sophisticated Use of Symbols

• Solving mental activities with x as a factor a
  part of formal operations stage
• Ability to manipulate symbols a part of formal
  operations stage
• Adolescents can analyze metaphors in literature.
• Adolescents may take on crystal clear solutions
  to religious, political, and social issues
  without tolerance for other issues that may be
  contributory.

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Adolescent Egocentrism

• Adolescents have difficulty sorting out issues
  that concern others from the things that concern
  themselves
• Imaginary audience
• Adolescent placed at center stage of fantasies
• Assumes others are concerned with their looks and
  dress
• Explains why adolescents engage in looking in the
  mirror so much
• Personal fable
• Belief that ones thoughts and emotions are
  unique and special
• Normal for male adolescent to think he is
  indispensable
• Reason STIs occur Cant happen to me
• Believe that no one has ever experienced the same
  things as themselves

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Gender Differences in Cognitive Abilities
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Verbal Ability

• As a group, females surpass males in verbal
  ability.
• Boys in the U.S. are more likely to be dyslexic
  and read below grade level.
• Culture and heredity play a role in the mastery
  of verbal ability.

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Visual-Spatial Ability

• Visual-spatial ability (VSB)
• The ability to visualize objects or shapes and to
  mentally manipulate and rotate them
• Important ability in art, architecture, and
  engineering
• By age 8 or 9, boys begin outperforming girls in
  VSB.
• Most notable on mental rotation tasks
• VSB ability of boys may be due to evolutionary
  factors as well as sex hormones.
• Environment plays a role
• Ex. toys for boys (Legos, Erector sets) versus
  the toys for girls
• Boys engage in more sports, which is associated
  with better performance of visual-spatial skills

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Fig. 11-6, p. 239
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Mathematical Ability

• Male adolescents generally outperform female
  adolescents especially in geometry and word
  problems.
• No sex differences in understanding math concepts
  at any age.
• Teaching expectations and involvement with math
  from dad contribute to mathematical advancement
  of boys girls less likely to be encouraged in
  math advanced teachers more likely male
  teachers spend more time helping males with math

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Moral Development
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Moral Development

• Many adolescents engage in postconventional moral
  reasoning.
• They deduce proper behavior
• Postconventional moral reasoning based on
  persons own moral standard and personal values
• Stages 5 and 6
• Stage 5
• Legalistic and contractual
• Laws stem from agreed upon procedures many
  rights have great value and should not be
  violated
• Stage 6
• Based on universal ethical principles of human
  life, individual dignity, and reciprocity
  (behavior that is consistent with these
  principles is considered right)

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Moral Behavior and Moral Reasoning

• Positive relationship between a persons level of
  moral development and his or her behavior
• Group discussion of moral dilemmas elevates
  delinquents level of moral reasoning

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Evaluation of Kohlbergs Theory

• Evidence supports that moral judgment develops in
  children in upward sequence.
• Postconventional thought first found in
  adolescents formal operational thinking a
  prerequisite
• Kohlberg underestimated the role of cultural,
  social, and educational institutions as well as
  parents.
• Postconventional thinking absent in developing
  countries and infrequent in the U.S. e.g.,
  principles such as freedom and tolerance of
  differences are not universally admired

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The Adolescent in School
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The Adolescent in School

• Adolescents are influenced by opinions of peers
  and teachers.
• Self-esteem reflective of their skills
• Middle-school teachers more likely to exert more
  behavioral control than teachers in elementary
  school
• Conflict arises
• Transition to middle and high school results in
  decline in grades and participation in school
  activities.
• More difficult for girls due to puberty
• Drop in self-esteem and increase in psychological
  distress
• Schools can ease distress by creating a warmer
  climate and establishing schools within a school.

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Dropping Out

• Early predictors
• Below grade-level reading and excessive absences
• Other factors
• Low SES, low grades, poor problem-solving
  ability, low self-esteem, problems with teachers,
  dissatisfaction with school, substance abuse,
  being old for ones grade level (retention is not
  the same as remediation), and being male
• Middle-class youth who feel bored with school,
  alienated, or strongly pressured to succeed are
  at risk.

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Preventing Drop Out

• Successful prevention programs include
• early preschool interventions
• identification and monitoring of high-risk
  students
• small class size, individualized instruction, and
  counseling
• vocational components that link learning to
  community work experiences
• involvement of families or community
  organizations
• positive school climate that provides clear and
  reasonable educational goals, student
  accountability for behavior, and motivational
  systems that involve penalties and rewards

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Adolescents in the Workforce
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Prevalence of Adolescent Employment

• One-half of high school sophomores, two-thirds of
  juniors, and almost three-fourths of seniors have
  a job during the school year.
• 2 to 3 million adolescents work illegally.
• Employed lower-income adolescents work longer
  hours than working middle-class teens.

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Pros and Cons of Adolescent Employment

• Potential benefits of employment include
• developing a sense of responsibility,
  self-reliance, and discipline
• learning to appreciate value of money and
  education
• acquiring positive work habits and values
• enhancing occupational aspirations
• Lower SES adolescents work to supplement family
  income.
• Middle-class teens use income for personal
  purchases, such as clothing, iPods, CDs, DVDs,
  gear, and car payments.

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Pros and Cons of Adolescent Employment (contd)

• Most working teens in jobs with low pay, high
  turnover, little authority, and little chance of
  advancement typically perform repetitive tasks.
• Teens working more than 11 to 13 hours per week
  have
• lower grades, higher rates of drug and alcohol
  use, more delinquent behavior, lower self-esteem,
  and higher levels of psychological problems than
  other students not working
• Working teens less monitored, spend fewer hours
  with family, and granted more decision-making
  power
• Hours worked per week needs to be limited