11: Physical and Cognitive Development in Adolescence

adolescents face

• dramatic biological changes

• new experience

• new developmental tasks

true or false. only 20 percent of U.S. 15-year-olds report having meaningful relationships with adults outside their family who are helping them to succeed

true

puberty

a brain-neuroendocrine process occurring primarily in early adolescence that provides stimulation for rapid physical development

• not a single, sudden event

• pinpointing its beginning and end is difficult

• Among the most noticeable changes are signs of sexual maturation and increases in height and weight

Male pubertal characteristics

• Increase in body size

• Appearance of pubic hair, armpit hair, facial hair, chest hair

• Voice change

Female pubertal characteristics

• marked weight and height gains

• pubic hair growth

• breast growth

• menarche: a girl’s first menstruation

hormones

a powerful chemical substances secreted by the endocrine glands and carried throughout the body by the bloodstream

• testosterone

• estradiol

hormones may contribute to psychological development; but social factors are important

behavior and mood can also affect hormones

testosterone

associated in boys with genital development, increased height, and deepening of the voice

estradiol

type of estrogen that in girls is associated with breast, uterine, and skeletal development

timing and variations in puberty

In the United States, the average age of menarche has declined significantly since the mid-nineteenth century

• factors include higher BMI and obesity

Experiences linked to earlier pubertal onset include nutrition, an urban environment, low SES, adoption, father absence, family conflict, maternal harshness, child maltreatment, and early substance use.

• For boys, the pubertal sequence begins around 10 to 13½ years of age and ends around 13 to 17.

• For girls, menarche normally occurs between ages 9 and 15.

body image

• Preoccupation with body image is strong throughout adolescence

• Girls are less happy with their bodies and have more negative body images

• One study found both boys’ and girls’ body images became more positive as they moved from the beginning to the end of adolescence.

Early and late maturation

Early-maturing boys view themselves more positively and have more successful peer relations.

Late-maturing boys report a stronger sense of identity in their thirties

• More time to explore life’s options

• focus on physical status instead of career and achievement

Recent research confirms that it is more advantageous to be an early-maturing boy than a late-maturing boy

Early-maturing girls show greater satisfaction early but less satisfaction later

• More likely to smoke, drink, be depressed, or have disorders

• Struggle for earlier independence, have older friends, have sexual intercourse earlier, and more at risk for physical and verbal abuse in dating

• Less likely to graduate from high school

• May cohabit and marry earlier

Physical maturity does not equal cognitive maturity, and girls may get involved with problem behaviors with long-term negative effects

corpus callosum

fibers connect the brain’s left and right hemisphere, thickens in adolescence

• improves the ability to process informaiton

prefrontal cortex

the highest level of the frontal lobes involved in reasoning, decision making, and self-control, doesn’t finish maturing until emerging adulthood or later

limbic system

the part of the brain where emotions and rewards are processed, is almost completely developed in early adolescence

• amygdala: the limbic system structure especially involved in emotion

Adolescence is a bridge between the asexual child and the sexual adult

It is a time of sexual exploration and experimentation, of sexual fantasies and realities, and of incorporating sexuality into one’s identity

• Insatiable curiosity about sexuality

• Concern with sexual attractiveness

• May experience vulnerability and confusion

In the United States, the sexual culture is widely available to adolescents

developing a sexual identity

mastering emerging sexual feelings and forming a sense of sexual identity involve

• learning to manage sexual feelings

• developing new forms of intimacy

• learning how to regulate sexual behavior

An adolescent’s sexual identity involves

• Activities and interests.

• Styles of behavior

• An indication of sexual orientation

It is commonly thought that gay and lesbian youth struggle with same-sex attractions in childhood, avoid heterosexual dating, and gradually recognize their sexual identity by late adolescents

Many follow a different pathway

• For some, the awareness of same-sex attraction is abrupt, in late adolescence

• The majority also experience some degree of other-sex attraction

The process is more stressful than for heterosexual youth, often including disclosing their sexual identity to family members

The timing of adolescent sexual behaviors

In a U.S. national survey conducted in 2019, 38.4 percent of ninth- to twelfth-graders reported having experienced sexual intercourse

• Sexual initiation varies by ethnic group in the United States

• Oral sex is common among U.S. adolescents

• How adolescents initiate their sex lives may have positive or negative consequences for their sexual health.

Risk factors in adolescent sexual behavior

Many adolescents are not emotionally prepared to handle sexual experiences

• early sexual activity is linked w/ risky behavior

• substance abuse, especially in early adolescence, is linked to sexual risk practices

Family factors that affect risk

• Family connectedness

• Parent-adolescent communication about sexuality

• Parental monitoring

• Siblings’ sexual activity

Peer, school, sport, and religious contexts also affect risk

• Association with more deviant peers increases risk

• School connectedness and academic achievement decrease risk

• Sports engagement—more sexual risk taking for boys who play sports; lower sexual risk taking for girls who do so

• Importance of religion

Cognitive factors implicated in sexual risk taking include weak self-regulation, and impulsiveness

Sexually transmitted infections (STIs)

infections contracted primarily through sexual contact, including oral-genital and anal-genital contact

• nearly half the new STI infections each year in the United States occur in 15-24 year olds

Adolescent pregnancy

The United States has one of the highest rates of adolescent pregnancy and childbearing in the industrialized world

• Note that where teens are just as sexually active, such as in the Netherlands, the pregnancy rate is still significantly lower

Adolescent pregnancy creates health risks for both the baby and the mother

• Low birth weight, neurological problems, childhood illness

• Most mothers drop out and never catch up economically

• Adolescent mothers often have depression and a second child, but education and LARC help reduce rates of both.

To improve adolescent health, adults should aim to

Increase health-enhancing behaviors.

• eating nutritious foods, exercising, wearing seat belts, getting adequate sleep

reduce adolescents’ health-compromising behaviors

• drug abuse, violence, unprotected sex, dangerous driving

Behaviors linked to both good and poor health habits in adulthood begin during adolescence

Nutrition and exercise:

• National data indicate over 20 percent of 12- to 19-year-olds are overweight.

• Fast-food meals, high in fat, are implicated, along with limited intake of fruits and vegetables, less exercise, and more sedentary activities—including high amounts of screen time

• Being obese in adolescence predicts obesity in adulthood

exercise is linked to numerous positive physical, cognitive, and emotional outcomes

sleep

• only about 25% percent of US adolescents get eight or more hours of sleep on an average school night

• low amounts of sleep and inconsistent sleep patterns are associated with

  • inattention

  • emotional and peer-related problems

  • higher anxiety and levels of suicidal ideation

• factors include electronic media, caffeine, and changes in the brain coupled with early school start times

Leading causes of death in adolescence:

• Unintentional injuries—almost half of all deaths

• Suicide

• Homicide

The majority of accidents involve a motor vehicle.

• Risky driving and driving under the influence may be more important contributors than lack of experience

• Of growing concern is the practice of mixing alcohol and energy drinks

• A high rate of intoxication is also found in adolescents who die as pedestrians or with a vehicle other than an automobile

Although overall drug use by adolescents has declined in recent decades, the United States still has one of the highest rates of adolescent drug use of any developed nation

Marijuana is the illicit drug most widely used.

Alcohol

• Binge drinking is defined as having five or more drinks in a row in the last two weeks

• Males engage in binge drinking more than females

• Significant declines in usage have been observed over in recent years

• Adolescents who drive under the influence are a special concern

Smoking

Cigarette smoking is one of the most serious yet preventable health problems among adolescents and emerging adults.

An increasing percentage of adolescents today perceive cigarette smoking as dangerous, and they are less accepting of being around smokers

However, a substantial number are now using e-cigarettes, which produce a vapor that users inhale

• In most cases the vapor contains nicotine, but specific formulas are not regulated

• e-Cigarettes have a gateway effect for cigarette smoking and marijuana use

The roles of development, parents, peers, and education:

Parents play an important role in preventing adolescent drug abuse

• Positive relationships with parents, parental monitoring, and regularly eating dinner together as a family are all linked with a lower likelihood of substance-abuse problems

• Heavy episodic drinking by parents is a risk factor for adolescent drinking.

Peers also play a significant role

Academic success is a strong buffer

anorexia nervosa

the relentless pursuit of thinness through starvation

Main characteristics:

• Restricted energy intake

• Presence of intense fear of gaining weight

• Disturbance in how body weight is experienced

• Obsessive thinking about weight and compulsive exercise

Anorexia is 10 times more likely in females

bulimia nervosa

an eating disorder in which the individual consistently follows a binge-and-purge pattern

Characteristics and traits of bulimics:

• preoccupied w/ food

• Have an intense fear of becoming overweight

• Are depressed or anxious

• Have a distorted body image

• Typically fall within a normal weight range

Formal operational thought is more abstract than concrete operational thought

• Increased verbal problem-solving ability

• Increased tendency to think about thought itself

• Thoughts of idealism and possibilities

• More logical thought

Hypothetical-deductive reasoning

the cognitive ability to develop hypotheses, or best guesses, about ways to solve problems

Adolescent egocentrism

heightened self-consciousness of adolescents

Imaginary audience

adolescents’ belief that others are as interested in them as they themselves are, as well as attention getting behavior motivated by a desire to be noticed (“on stage”).

Personal fable

the part of adolescent egocentrism that involves a sense of uniqueness and invincibility

• Research shows, however, that adolescents tend to portray themselves as vulnerable to premature death

A recent study found greater use of social networking to be linked to a higher level of narcissism

Important characteristics of adolescents’ information processing and thinking, as identified by Deanna Kuhn

• Individuals approach cognitive levels that may or may not be achieved

• Considerable variation in cognitive functioning is present across individuals

• Adolescents are producers of their own development to a greater extent than are children

• The most important cognitive change is in executive function— especially, managing one’s thoughts to engage in goal-directed behavior and to exercise self-control.

Two categories of executive function

Cool executive function: psychological processes involving conscious control driven by logical thinking and critical analysis

• Increases with age.

Hot executive function: psychological processes drive by emotion, with emotion regulation an especially important process

• Peaks at 14 to 15 years of age, then declines

Cognitive control

exercising effective control of thinking in a number of areas

• Focusing attention, reducing interfering thoughts, and being cognitively flexible

• Increases in adolescence and emerging adulthood

Adolescence is a time of increased decision making, but also a time of intense emotions that can overwhelm decision making

The social context plays a key role in adolescent decision making, especially with regard to risk-taking situations

Fuzzy-trace theory dual-process model

decision making is influenced by two systems—“verbatim” analytical and gist-based intuition

• The verbatim analytical system is literal and precise

• Gist-based intuition is based on the simple, bottom-line meaning

• The two operate in parallel.

Valeria Reyna and colleagues propose that gist-based intuition benefits adolescent decision making more than analytical thinking does.

Adolescents need opportunities to practice and discuss realistic decision making.

Critical thinking

For individuals who still lack fundamental skills (such as literacy and math skills) in adolescence, potential gains in adolescent thinking are unlikely.

For most, certain cognitive changes in adolescence allow improved critical thinking

• Increased speed, automaticity, and capacity of information processing

• More breadth of content knowledge in a variety of domains

• Increased ability to construct new combinations of knowledge

• Greater range and more spontaneous use of strategies for applying or obtaining knowledge

Top-dog phenomenon

moving from being the oldest, biggest, most powerful in elementary school to being the youngest, smallest, and least powerful in middle or junior high school

• middle school students have a lower level of self-concept in a number of areas than elementary school students; and teacher warmth drops

Positive aspects include feeling more grown up, more subjects to choose from, more time with peers, increased independence, and intellectually challenging academic work

In 1989, the Carnegie Corporation recommended

• Smaller “communities” or “houses” that lessen the impersonality of middle schools

• Lower student-to-counselor ratios

• Involving parents and community leaders

• Developing new curricula and having teachers team-teach in curriculum blocks that integrate several disciplines

• Boosting students’ health and fitness with in-school programs

• Helping students who need public health care to get it

Experts today still find schools need a major redesign.

To combat the issues faced by students:

• Increase school counseling services

• Expand extracurricular activities

• Improve parental monitoring

To rectify dropping out, early intervention and mentoring helps.

• Dropout rates vary among ethnic groups

• The National “I Have a Dream” Foundation has promoted significant improvements.

Service learning

form of education that promotes social responsibility and service to the community

• Tutoring, helping older adults, working in a hospital, assisting in a child-care center, cleaning up a vacant lot for a play area

• An important goal is becoming less self-centered and more strongly motivated to help others

• It is often more effective when it gives students some degree of choice in activities and provides opportunities to reflect on their participation

Benefits include higher grades, increased goal setting, higher self-esteem, a greater sense of being able to make a difference, and opportunities to explore and reason about moral issues