Senescence
1. Senescence causes a universal slowdown during adulthood, but aging is often imperceptible because organ reserve maintains capacity. The entire body adjusts to changes in the short term (homeostasis) and the long term (allostasis).
2. Sexual satisfaction may improve with age, but infertility becomes more common. Sperm count gradually decreases in men, and every step of female reproduction—
3. A number of assisted reproductive technology (ART) procedures, including in vitro fertilization (IVF), offer potential answers to infertility. Donor sperm, donor ova, and/or donor wombs have helped millions of infertile couples become parents.
4. The brain slows down and begins a gradual decline. The brain benefits from measures to improve overall health, especially exercise, and is harmed by most psychoactive drugs.
5. Senescence is apparent in the senses, notably vision and hearing. Everyone becomes more far-
6. Appearance also changes with age, as evident in less elastic skin, more wrinkles, less hair, and more fat. Ease of movement decreases as people become less agile.
7. At menopause, ovulation ceases and estrogen is markedly reduced. Hormone production declines more gradually in men. For both sexes, hormone replacement therapy (HRT) should be used cautiously, if at all.
Health Habits and Age
8. Mortality, morbidity, disability, and vitality are all measures of health, each overlapping but distinct. During adulthood (ages 25 to 65), mortality is unusual in developed nations, unless drug abuse (including smoking and drinking) is severe.
9. Adults in North America smoke cigarettes much less often than they once did, and rates of lung cancer and other diseases are falling, largely for that reason. Alcohol abuse remains a major health problem worldwide.
10. Good health habits include exercising regularly and maintaining a healthy weight. On both these counts, today’s adults are less healthy than prior generations. This is especially true in North America.
11. People experience many stresses over the 40 years of adulthood. They use various coping measures, both problem-
What Is Adult Intelligence?
12. It was traditionally assumed that there is one general intelligence (g), measurable by IQ tests. Cross-
13. Much depends on how intelligence is defined and measured. Crystallized intelligence, reflecting accumulated knowledge, increases, but fluid, flexible reasoning declines in adults.
14. Sternberg proposed three fundamental forms of intelligence: analytic, creative, and practical. Cultural values encourage development of some cognitive abilities more than others. Each person responds to these cultural priorities, which may not be reflected in IQ scores.
Selective Gains and Losses
15. As people grow older, they select certain aspects of their lives to focus on, optimizing development in those areas and compensating for declines in others. Applied to cognition, this means that people become selective experts in whatever intellectual skills they choose to develop. Meanwhile, abilities that are not exercised may fade.
16. In addition to being more experienced, experts are better thinkers than novices because they are more intuitive; their cognitive processes are automatic, often seeming to require little conscious thought; they use more and better strategies to perform whatever task is required; and they are more flexible in their thinking.
17. Experienced adults may surpass younger adults if they specialize and harness their efforts, compensating for any deficits that may appear. According to a study of taxi drivers in London, England, brains grow to support selective expertise.