2. Emerging Adulthood Period between the ages of 18 and 25, which is now widely thought of as a separate developmental stage Millions of young people now hover before full adulthood Lane Oatey/Blue Jean Images/Getty Images

3. Growth and Strength Strong and active bodies Emerging adults are usually in good health. Traditionally, ages 18 and 25 were a time for hard physical work and childbearing. Physical work and parenthood are no longer expected of every young adult in the 21 st century. AP PHOTO/AXEL HEIMKEN

4. Growth and Strength Because of food availability, most emerging adults have reached full height (girls usually by age 16, boys by age 18). Muscle growth and fat accumulation continue into the early 20s, when women attain adult breast and hip size and men reach full shoulder width and upper-arm strength. Death from disease almost never occurs during emerging adulthood.

5. Strong and Independent

6. Bodies in Balance Emerging adulthood By age 20, the immune system is well-developed Usually, blood pressure is normal, teeth develop no new cavities, heart rate is steady, the brain is fully grown, and lung capacity is as large as it will ever be. Senescence The process of aging, whereby the body becomes less strong and efficient. Begins in late adolescence

7. Dirty Hands Once men avoided hand washing—it was too ladylike. Then scientists proved that hand contact spread every virus, from the common cold to SARS. Here famed Ferrari driver Fernando Alonso joins a UNICEF hand-washing day, showing a young lad in India that he should wash his knuckles too. PUNIT PARANJPE/AFP/GETTY IMAGES

8. Unused Potential Organ reserve The capacity of organs to allow the body to cope with stress, via extra, unused functioning ability Maximum strength potential Begins to decline by age 25 Fifty-year-olds retain 90% of muscle reserve they had at age 20

9. Bodies in Balance Homeostasis The adjustment of all the body’s systems to keep physiological functions in a state of equilibrium. As the body ages, it takes longer for these adjustments to occur, so it becomes harder for older bodies to adapt to stress. Nutrition and exercise underlie health at every age. Allostasis Dynamic body adjustment that affects overall physiology Homeostasis requires an immediate response from the body systems, whereas allostasis refers to longer- term adjustment. Allostatic load refers to the wear and tear on the body that results from either too much stress or inefficient management of stress.

10. Why do developmental scientists cluster adults into chronological age groups, reporting differences between one group and another? Age matters to adults as they journey through the life span. Cohorts matters. Maturation and experience accumulate. Ages and Stages

11. All Three Together Interaction of organ reserve to homeostasis and allostasis Health habits in emerging adulthood affect vitality in old age All three aspects of body functioning work well in young adults Senescence gradually increases allostatic load

12. Appearance Most emerging adults look vital and attractive Vanity about personal appearance not readily admitted, but observable Attraction to fashion and glamorous celebrities Money spent on fashion Exercise motivated by desire to look fit and attractive Appearance concern may be connected to sex drive or employment-seeking

13. Staying Healthy Exercise Reduces blood pressure, strengthens the heart and lungs Makes depression, osteoporosis, heart disease, arthritis and some cancers less likely Those who are not fit during emerging adulthood are 4 times more likely to have diabetes and high blood pressure 15 years later. Factors encouraging exercise Friendship Communities

14. Staying Healthy Eating well At every stage of life, diet affects future development. Set point A certain body weight that a person’s homeostatic processes strive to maintain Body mass index (BMI) The ratio of a person’s weight in kilograms divided by their height in meters squared

15. Staying Healthy CARDIA study Specifics of diet matter Fast foods, high-fat diets, and diet soda each had independent effects Overall result affect not only body weight, but also other health factors indicated by laboratory tests

16. Sexual Activity The sexual-reproductive system is especially vigorous. Sexual-reproductive characteristics are produced by peaked sex hormones. The sex drive is powerful, infertility is rare, orgasm is frequent, and birth is easy, with fewer complications in the early 20s than at any other time.

17. Sexual Activity Average woman in her early 20s becomes pregnant within three months. Globalization, advanced technology, and modern medicine have combined to produce effective contraception, available in almost every nation. As fewer infants die, people no longer need to begin childbearing before age 20 or have four or more children simply to ensure that some children will survive.

18. Sexual Activity Advances in contraception have reduced the birth rate and have also increased the rate of sexual activity. Globally, emerging adults have fewer babies but engage in more sexual activity. Half of all emerging adults in U.S. have had at least one sexually transmitted infection (STI).

19. Opinions and Problems Sexually transmitted infections (STIs) STIs have always been present but the rate has reached epidemic proportions due to sexual patterns. Half of all new cases worldwide occur in people younger than 26. Best way to prevent STIs is lifelong monogamy Worldwide, globalization fuels every contagious disease. AIDS has become a worldwide epidemic, with more heterosexual females than gay males testing positive for HIV.

20. Emotional Stress One consequence of current sexual patterns may be emotional stress as relationships begin and end. Attitudes about the purpose of sex –Reproduction –Relationship –Recreation If partners have differing ideas about the purpose of sex or the nature of gender, emotional pain and frustration can occur (unanticipated emotional entanglement).

21. Psychopathology Multiple stresses of emerging adults Demands of emerging adulthood may cause psychopathology when added to preexisting vulnerability. Incidence of psychopathology increases in emerging adulthood Rate of serious mental illness is almost double that for adults over age 25 Diathesis-stress model View that mental disorders are produced by the interaction of genetics (diathesis) and a stressful environment and life events.

22. Mood Disorders Before they reach age 30, 8% of U.S. residents suffer from a mood disorder: mania, bipolar disorder, or severe depression. Major depressive disorder Most common mood disorder A loss of interest or pleasure for 2 weeks or more May be rooted in imbalances in neurotransmitters and hormones

23. Anxiety Disorders Symptoms of anxiety disorders are shaped by age and genetic vulnerability. Include panic attacks, post- traumatic stress disorder (PTSD), and obsessive- compulsive disorder (OCD) Evident in one-fourth of all U.S. residents below 25 More common, worldwide than depression Hikikomori Common among young adults in Japan Victims isolate themselves for months or years Recovering from hikikomori JAMES WHITLOW DELANO/REDUX

24. Schizophrenia Symptoms usually begin in adolescence Involves about 1% of adults Characterized by disorganized and bizarre thoughts, delusions, hallucinations, and emotions Risk factors Genetic, malnutrition when brain is developing, social pressure

25. Taking Risks Emerging adulthood is marked by a greater willingness to take risks of all sorts, not just sexual ones. Young adults enjoy danger, drive without seat belts, carry guns, try addictive drugs. Reasons for such risk-taking are both social and biological.

26. Seven Serious Years

27. Taking Risks Edgework Occupations, recreational activities, or other ventures that involve a degree of risk or danger Prospect of “living on the edge” makes edgework compelling to some individuals Extreme sports Forms of recreation that include apparent risk of injury or death and that are attractive and thrilling as a result

28. Drug Abuse Drug abuse Ingestion of a drug to the extent that it impairs the user’s biological or psychological well-being Drug addiction Condition of drug dependence in which the absence of the given drug from the individual’s system produces a drive—physiological, biological, or both—to ingest more of the drug

29. Too Old for That

30. Drug Abuse Drug abuse is particularly common among those who die violently. In the U.S., between the ages of 15 and 25, almost 1 male in every 100 dies violently, through suicide, homicide, or a motor-vehicle accident. About 4 times as many young men as young women commit suicide or die in motor-vehicle accidents, and 6 times as many are murdered.

31. Social Norms Social norms Are customs for usual behavior within a particular society Exert strong influence on emerging adults, including college students Social norms approach A method of reducing risky behavior among emerging adults that is based on their desire to follow social norms. This approach publicizes survey results to make emerging adults aware of the actual prevalence of various behaviors within their peer group.

32. Social Norms Base rate neglect Involves tendency to overlook or ignore the frequency of a specific factor when making a judgment or decision, even in the face of overwhelming odds Availability error Occurs when people remember most easily the events or people who make a dramatic impact