10.5 SUMMARY

• Developmental psychology studies continuity and change across the life span.
• The prenatal stage of development begins when a sperm fertilizes an egg, producing a zygote, which contains chromosomes from both the egg and the sperm. The zygote develops into an embryo at 2 weeks and then into a fetus at 8 weeks.
• The fetal environment has important physical and psychological influences on the fetus. In addition to the food a pregnant woman eats, teratogens, or agents that impair fetal development, can affect the fetus. Some of the most common teratogens are tobacco and alcohol.
• In the womb, the fetus can hear sounds and become familiar with those it hears often, such as its mother’s voice.

• Infants learn to control their bodies from the top down and from the center out.
• Infants slowly develop theories about how the world works. Piaget believed that these theories developin four stages, in which children learn basic facts about the world.
• Cognitive development also comes about through social interactions in which children are given tools for understanding that have been developed by members of their cultures.
• At a very early age, human beings develop strong emotional ties to their primary caregivers. The quality of these ties is determined both by the caregiver’s behavior and the child’s temperament.
• Children’s reasoning about right and wrong is initially based on an action’s consequences, but as they mature, children begin to consider the actor’s intentions as well as the extent to which the action obeys abstract moral principles.

• Adolescence is a stage of development that begins at puberty, which is the onset of sexual maturity of the human body.
• Adolescents are somewhat more prone to do things that are risky or illegal, but they rarely inflict serious or enduring harm on themselves or others.
• During adolescence, sexual interest intensifies, and in some cultures, sexual activity begins. Although most people are attracted to members of the opposite sex, some are not, and research suggests that biology plays a key role in determining a person’s sexual orientation.
• As adolescents seek to develop their adult identities, they seek increasing autonomy from their parents and become more peer-oriented, forming single-sex cliques, followed by mixed-sex cliques, and finally pairing off as couples.

• Gradual physical decline begins early in adulthood and has clear psychological consequences.
• Older adults show declines in working memory, episodic memory, and retrieval tasks, but they often develop strategies to compensate.
• Older people are more oriented toward emotionally satisfying information, which influences their basic cognitive performance, the size and structure of their social networks, and their general happiness.
• People who get married are typically happier, but children and the responsibilities that parenthood entails present a significant challenge, especially for women.