18.8 Chapter 8: Human Development

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1. development
2. Developmental psychologists’ longstanding discussions have centered on three major themes: stages and continuity; nature and nurture; and stability and change. Each of these themes relates to a basic question: (1) Does development occur in separate or discrete stages, or is it a steady, continuous process? (2) What are the relative roles of heredity and environment in human development? (3) How stable is one’s personality over a lifetime and across situations?
3. c. cross-sectional

1. d. Chromosomes
2. Genotype; phenotype
3. a. embryonic period
4. Genes are behind most human traits, from shoe size to behavior. Each chromosome pair provides us with two versions of a gene: We acquire one gene from our biological mother and the other from our biological father. In some cases, the genes are identical. In other cases, the genes in a pair provide conflicting instructions about the outcome of some characteristic. Often one gene variant has more power than the other. This dominant gene then directs the expression of the inherited characteristic, overpowering the recessive, or subordinate, gene in the pair. A recessive gene cannot overcome the influence of a dominant gene. For example, the gene responsible for cystic fibrosis is recessive. If a child inherits the cystic fibrosis gene from one parent and a normal gene from the other parent, the disease gene will not be expressed (she will not develop cystic fibrosis). However, if she inherits the cystic fibrosis gene from both parents, the gene will be expressed (she will develop the disease).

1. rooting; sucking
2. a. theories of behaviorism
3. d. assimilation.
4. scaffolding
5. c. developmental tasks or emotional crises.
6. There is a universal sequence of language development. At around 2–3 months, infants typically start to produce vowel-like sounds known as cooing. At 4–6 months, in the babbling stage, infants combine consonants with vowels. This progresses to the one-word stage around 12 months, followed by two-word telegraphic speech at approximately 18 months. As children mature, they start to use more complete sentences. Infants pay more attention to adults who use infant-directed speech and are more likely to provide them with chances to learn and interact, thus allowing more exposure to language. Parents and caregivers should talk with their infants and children as much as possible, as babies benefit from a lot of chatter.

1. b. secondary sex characteristics.
2. a. formal operational stage.
3. Preconventional
4. Answers will vary. During the stage of ego identity versus role confusion, an adolescent seeks to define himself through his values, beliefs, and goals. If a helicopter parent has been troubleshooting all of her child’s problems, the child has never had to learn to take care of things for himself. Thus, he may feel helpless and unsure of how to handle a problem that arises. The parent might also have ensured the child was successful in every endeavor, but this too could cause the child to be unable to identify his true strengths, again interfering with the creation of an adult identity.

1. a. physical exercise
2. fluid; crystallized
3. d. acceptance
4. integrity; despair
5. Answers will vary, but can be based on the following definitions. Parents who insist on rigid boundaries, show little warmth, and expect high control exhibit authoritarian parenting. Parents who practice authoritative parenting set high expectations, demonstrate a warm attitude, and are highly responsive to their children’s needs. Parents who place very few demands on their children and do not set many limitations exhibit permissive parenting. Uninvolved parenting refers to parents who seem to be indifferent, are emotionally uninvolved with their children, and do not exhibit warmth, although they provide for their children’s basic needs.

1. b. longitudinal research.
2. d. nature and nurture
3. d. genes
4. a. epigenetics.
5. c. synaptic pruning
6. d. Teratogens
7. b. babbling
8. c. trust versus mistrust
9. b. scaffolding
10. c. Primary sex characteristics
11. a. formal operational stage.
12. b. search for identity
13. d. menopause
14. b. longitudinal method.
15. a. denial
16. Answers may vary. Family: social. Learning: psychological, social. Media: social, psychological. Heredity: biological. Hormones: biological. Traits: biological, psychological, and social. Culture: psychological, social.
17. At conception, when a sperm and egg merge, they form a single cell called a zygote. During the germinal period, the zygote grows through cell division and eventually becomes implanted in the uterine wall. Between the 3rd and 8th weeks of development, the mass of cells is now called an embryo. The embryo begins to develop everything the baby will need to live. The fetal period begins at the 9th week and continues until birth. Overall growth of the body and development of organ systems in the fetus is taking place. By the time a baby reaches this stage, everything that it needs to become a new person is already in place; it just needs to grow, develop, and become more mature.
18. Infant-directed speech (IDS) is observed throughout the world. Infants as young as 5 months old pay more attention to people who use infant-directed speech. It helps a child to learn to interact with “appropriate social partners,” or adults who are more likely to provide them with such chances. From an evolutionary perspective, IDS helps a baby know who is going to pay the most attention to her, and who is going to protect and guide her. It also ensures that the infant will be enriched by interactions with others.
19. Answers will vary. Authoritarians give strictness; authoritative give warmth; permissive give permission; uninvolved give little.
    Authoritarian parenting; authoritative parenting; permissive parenting; uninvolved parenting.
20. Wisdom improves with age through an accumulation of instructive life experiences. As it increases, we make better decisions when encountering daily problems. Practical abilities also seem to increase. Experiences allow people to develop a more balanced understanding of the world surrounding them.

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ANSWER: Independent variable: level of environmental stimulation (enriched environment, standard colony cages, or isolation cages). Dependent variable: changes in brain development.