Chapter 11 Physical and Cognitive Development in Adolescence ©2005 McGraw-Hill Ryerson Ltd.
Nature of Adolescence • Genetic, biological, environmental, and social factors interact in teen development. • Continuity and discontinuity both play a role. • Relationships with parents take a different form. • Dating occurs for the first time. • Thoughts are more abstract and idealistic. • Biological changes trigger a heightened interest in body image. • Most adolescents have a positive self-concept and positive relationships with others. ©2005 McGraw-Hill Ryerson Ltd.
Definition of Puberty • Puberty is a period of rapid physical maturation involving hormonal and bodily changes that occur primarily during early adolescence. ©2005 McGraw-Hill Ryerson Ltd.
Individual Variation in Puberty • Boys – pubertal sequence begins between ages 10 and 13 ½ • Girls – normal range is between 8 and 16 (onset of menarche, or first menstrual period). • Puberty determinants include: • Nutrition • Health • Heredity • Body mass ©2005 McGraw-Hill Ryerson Ltd.
What are Hormones? • Powerful chemical substances secreted by the endocrine glands and carried through the body by the bloodstream ©2005 McGraw-Hill Ryerson Ltd.
Endocrine System • Hypothalamus – a structure in the higher portion of the brain that monitors eating, drinking, and sex • Pituitary gland – an endocrine gland that controls growth and regulates other glands • Gonads – the sex glands (testes in males, ovaries in females) • Gonadotropins – hormones that stimulate the testes or ovaries ©2005 McGraw-Hill Ryerson Ltd.
Hormonal Changes • The endocrine system’s role in puberty involves interaction of the hypothalamus, pituitary gland, and gonads. • The pituitary gland also interacts with the thyroid gland to produce growth and skeletal maturation. • The concentrations of certain hormones increase dramatically during adolescence. • Hormones contribute to both physical and psychological development. ©2005 McGraw-Hill Ryerson Ltd.
Height and Weight • Growth spurt – occurs about 2 years earlier for girls. • Mean beginning of the growth spurt – age 9 for girls; age 11 for boys. • Peak rate of pubertal change – age 11.5 for girls; age 13.5 for boys. • Increase in height – about 9 cm per year for girls; about 10.6 cm for boys. • The rate at which adolescents gain weight follows approximately the same timetable as height. ©2005 McGraw-Hill Ryerson Ltd.
Sexual Maturation in Boys • Increase in penis and testicle size • Appearance of straight pubic hair • Minor voice change • First ejaculation • Appearance of kinky pubic hair • Onset of maximum growth • Growth of hair in armpits • More detectable voice change • Growth of facial hair ©2005 McGraw-Hill Ryerson Ltd.
Sexual Maturation in Girls • Breasts enlarge • Pubic hair appears • Hair appears in the armpits • Growth in height • Hips become wider than shoulders • First menstruation comes rather late in puberty • Menstrual cycles are often highly irregular • Some girls aren’t fertile until 2 years later • Breasts are fully rounded by the end of puberty ©2005 McGraw-Hill Ryerson Ltd.
Body Image • Adolescents are preoccupied with their bodies and develop individual images of what their bodies are like. • Adolescents are more dissatisfied with their bodies during puberty than in late adolescence. • Girls are less happy with their bodies and have more negative body images than boys throughout puberty. • As pubertal change proceeds, girls often become more dissatisfied with their bodies due to the increase in body fat, while boys become more satisfied due to the increase in muscle mass. ©2005 McGraw-Hill Ryerson Ltd.
Early and Late Maturation in Boys • Recent research confirms that during adolescence, it is advantageous to be an early-maturing rather than late-maturing boy. • Early maturing boys appear to perceive themselves more positively and have more successful peer relations than their late-maturing counterparts. ©2005 McGraw-Hill Ryerson Ltd.
Early and Late Maturation in Girls • Recent findings suggest that early-maturing girls experience more problems in school. • They also experience more independence and popularity with boys. • In sixth grade, early-maturing girls show greater satisfaction with their figures, but by tenth grade, late-maturing girls are more satisfied. ©2005 McGraw-Hill Ryerson Ltd.
Adolescent Sexuality • Adolescence is a time of sexual exploration and experimentation. • Adolescence is a bridge between the asexual child and the sexual adult. • Sexual development and interest are normal aspects of adolescent development. • The majority of adolescents have healthy sexual attitudes and engage in sexual practices that will not compromise their development. ©2005 McGraw-Hill Ryerson Ltd.
Developing a Sexual Identity • An adolescent’s sexual identity involves: • an indication of sexual orientation • activities • interests • styles of behaviour ©2005 McGraw-Hill Ryerson Ltd.
The Progression of Adolescent Sexual Behaviour • Adolescents engage in a consistent progression of sexual behaviours: • Necking • Petting • Intercourse/Oral sex • Eight in 10 girls are virgins at age 15. • Seven in 10 boys are virgins at age 15. • The probability that adolescents will have sexual intercourse increases steadily with age. ©2005 McGraw-Hill Ryerson Ltd.
Risk Factors and Sexual Problems • Adolescents who engage in sex before age 16 are the least effective users of contraception. • They are also at risk for unintended pregnancy and sexually transmitted diseases. • Early sexuality is also linked with excessive drinking and drug use. ©2005 McGraw-Hill Ryerson Ltd.
Contraceptive Use • Two kinds of risks that youth encounter: • unintended/unwanted pregnancy • sexually transmitted diseases • Both of these risks can be reduced significantly if contraception is used. • Adolescents are increasing contraceptive use. • Younger adolescents are less likely to use them. • http://vad.mhhe.com/provided_module.cfm?ModuleID=222 (Adolescents' Changing Bodies: “Using Contraception at Age 15”) ©2005 McGraw-Hill Ryerson Ltd.
Sexually Transmitted Infections and Diseases • Sexually transmitted diseases (STDs) are contracted primarily through sexual contact, which is not limited to sexual intercourse. Oral-genital and anal-genital contact also can be involved in STDs. • Chlamydia and gonorrhea are more common among adolescents than young adults. ©2005 McGraw-Hill Ryerson Ltd.
Adolescent Pregnancy • Each year, more than 40,000 Canadian teenagers become pregnant. • The teen pregnancy rate did decline slightly in the 1990s. • Most adolescent pregnancies are unplanned. • Regional differences exist across Canada. ©2005 McGraw-Hill Ryerson Ltd.
Consequences of Adolescent Pregnancy • Adolescent pregnancy creates health risks for both the offspring and the mother. • Infants born to teen mothers are more likely to have: • low birthweights • neurological problems • childhood illness • Adolescent mothers often drop out of school. ©2005 McGraw-Hill Ryerson Ltd.
Reducing Adolescent Pregnancy • Sex education and family planning • Access to contraceptive methods • The life-options approach • Broad community involvement and support • Abstinence, especially for young adolescents ©2005 McGraw-Hill Ryerson Ltd.
Teen Depression • Depression is defined as experiencing over a prolonged period of time a range of symptoms including fatigue, irritability, inability to make decisions, sleeping problems, lack of interest in daily activities, and suicidal thoughts. • Boys were half as likely to suffer from depression. ©2005 McGraw-Hill Ryerson Ltd.
Higher Rates of Depression in Females • Females tend to internalize emotions. • Females tend to ruminate in their depressed mood and amplify it. • Females’ self-image, especially their body images, are more negative than those of males. • Females face more discrimination than do males. ©2005 McGraw-Hill Ryerson Ltd.
Substance Use and Addiction • Dopamine in the Brain • Alcohol • Cigarette Smoking • Gambling ©2005 McGraw-Hill Ryerson Ltd.
Dopamine in the Brain • Dopamine is one of the key brain chemicals that carry and influence messages between nerve cells. • It is heavily involved with pleasure – reward circuit of the brain. • All addictive drugs artificially increase the amount of dopamine in the reward centres of the inner brain by either jump-starting its release or prolonging its stay. ©2005 McGraw-Hill Ryerson Ltd.
Alcohol • Alcohol is the drug most widely used by adolescents in our society. • Since 1980, alcohol related deaths among teenage drivers has dropped by 61% in Canada. ©2005 McGraw-Hill Ryerson Ltd.
Cigarette Smoking • Begins primarily during childhood and adolescence. • A study found that once young adolescents begin smoking, the addictive properties of nicotine make it extremely difficult for them to stop. • The early age of onset of smoking is more important in predicting genetic damage than how much individuals smoke. ©2005 McGraw-Hill Ryerson Ltd.
Gambling • Gambling is a hidden addiction because it has no visible signals. • About 80% of Canadians gamble. • The number of pathological gamblers in Canada may be as high as 1.2 million. • Gambling has become increasingly popular with high school students. ©2005 McGraw-Hill Ryerson Ltd.
Risk, Vulnerability, and the Role of Parents and Peers • Drug use in childhood or early adolescence has more detrimental long-term effects on the development of responsible, competent behaviour than when drug use occurs in late adolescence. • Positive relationships with parents and others are important in reducing adolescents’ drug use. • Adolescents are most likely to take drugs when both of their parents take drugs and when their peers take drugs. ©2005 McGraw-Hill Ryerson Ltd.
Eating Disorders • Anorexia Nervosa • Bulimia Nervosa • http://vad.mhhe.com/provided_module.cfm?ModuleID=222 (Adolescents' Changing Bodies: “Eating Disorders”) ©2005 McGraw-Hill Ryerson Ltd.
Anorexia Nervosa • An eating disorder that involves the relentless pursuit of thinness through starvation; can lead to death. • Anorexics often weigh less than 85% of what is considered normal. • They have an intense fear of gaining weight, which does not dissipate with weight loss. • They also have a distorted image of their body shape and constantly weigh themselves. • Most are White adolescent or young adult females from well-educated, middle and upper income families. • They set high standards and stress at not reaching them. ©2005 McGraw-Hill Ryerson Ltd.
Bulimia Nervosa • An eating disorder in which the individual consistently follows a binge-and-purge eating pattern. • Purging is accomplished through self-inducing vomiting or use of a laxative. • Most bulimics are females in their late teens or early twenties. • Most bulimics are preoccupied with food, have a strong fear of becoming overweight, and are depressed or anxious. • Unlike anorexia, bingeing and purging occurs within a normal weight range and is difficult to detect. ©2005 McGraw-Hill Ryerson Ltd.
Leading Causes of Death in Adolescence • Accidents – most involve automobiles, and are the result of risky driving habits and driving under the influence of alcohol or drugs. • Suicide – accounts for 6% of the deaths in the 10–14 age group, and 12% of deaths in the 15 – 19 age group. • Alcohol and Illicit Drug Use– being under the influence of alcohol or drugs may result in riskier behaviour, which in turn results in more accident fatalities. ©2005 McGraw-Hill Ryerson Ltd.
Piaget’s Theory • Adolescent thought is at the formal operational stage. • Thought is more abstract, characterized by: • verbal problem-solving ability • increased tendency to think about thought itself • idealism and possibilities • more logical • hypothetical-deductive reasoning ©2005 McGraw-Hill Ryerson Ltd.
Hypothetical-Deductive Reasoning • Piaget’s formal operational concept that adolescents have the cognitive ability to develop hypotheses, or best guesses, about ways to solve problems, such as an algebraic equation. They then systematically deduce, or conclude, which is the best path to follow in solving the equation. ©2005 McGraw-Hill Ryerson Ltd.
Adolescent Egocentrism • The heightened self-consciousness of adolescents, reflected in their belief that others are as interested in them as they themselves are, and in their sense of personal uniqueness. • Dissected into two types of social thinking: • imaginary audience • personal fable ©2005 McGraw-Hill Ryerson Ltd.
Imaginary Audience • Refers to the heightened self-consciousness of adolescents, reflected in their belief that others are as interested in them as they themselves are. • Involves attention-getting behaviour—the attempt to be noticed, visible, and “on stage.” ©2005 McGraw-Hill Ryerson Ltd.
Personal Fable • The part of adolescent egocentrism involving an adolescent’s sense of uniqueness and invulnerability. • Adolescents feel that no one can understand how they really feel. • Personal fables frequently show up in adolescent diaries. ©2005 McGraw-Hill Ryerson Ltd.
Information Processing • Decision Making • Critical Thinking ©2005 McGraw-Hill Ryerson Ltd.
Decision Making • Adolescence is a time of increased decision making. • Compared with children, young adolescents are more likely to generate options, examine a situation from a variety of perspectives, anticipate the consequences of decisions, and consider the credibility of sources. • Parents should involve adolescents in appropriate decision-making activities. ©2005 McGraw-Hill Ryerson Ltd.
Critical Thinking • A solid basis of fundamental skills is necessary for the development of critical thinking skills. • Recent studies have shown critical thinking increases with age, but still only occurs less than half the time with eleventh grade students. • Cognitive changes that allow improved critical thinking are: • increased speed and capacity of information processing • more breadth of content knowledge in a variety of areas • increased ability to construct new knowledge combinations • a greater range and more spontaneous use of strategies ©2005 McGraw-Hill Ryerson Ltd.
Education • Effective Schools • High School Dropouts ©2005 McGraw-Hill Ryerson Ltd.
Effective Schools • Effective schools offer more than the “3 Rs”; they are accountable and responsible to public scrutiny. • Trademarks of effective schools: • Effective leadership • Clear academic goals • A safe and orderly climate • Expectation of minimum mastery of skills • Testing for program evaluation and redirection • Parental involvement • Collegiality ©2005 McGraw-Hill Ryerson Ltd.