Guidepost 1 What purposes do theories serve?

• A theory is used to explain data and generate hypotheses that can be tested by research.

Guidepost 2 What are the three basic theoretical issues on which developmental scientists differ?

• Developmental theories differ on three basic issues: the relative importance of heredity and environment, the active or passive character of development, and the existences of stages of development.
• Some theorists subscribe to a mechanical model of development; others to an organismic model.

Guidepost 3 What are five theoretical perspectives on human development, and what are some theories representative of each?

• The psychoanalytic perspective sees development as motivated by unconscious emotional drives or conflicts. Leading examples are Freud's and Erikson's theories.
• The learning perspective views development as a result of learning based on experience. Leading examples are Watson's and Skinner's behaviorism and Bandura's social learning theory.
• The cognitive perspective is concerned with thought processes. Leading examples are Piaget's cognitive-stage theory, the information-processing approach, and the cognitive neuroscience approach.
• The logical perspective describes adaptive behaviors that promote group survival.
• The contextual perspective focuses on interactions between the individual and the social context. Leading examples are Bronfenbrenner's and Vygotsky's theories.

Guidepost 4 How do developmental scientists study children, and what are some advantages and disadvantages of each research method?

• Research can be quantitative, qualitative, or both.
• To arrive at sound conclusions, quantitative researchers use the scientific method.
• Random selections of a research sample can ensure generalizability.
• Three forms of data collection are self-reports (diaries, interviews, and questionnaires); behavioral and performance measures; and observation.
• Four basic qualitative designs used in developmental research are the case study and ethnographic study. Two quantitative designs are the correlational study and the experiment. Only experiments can firmly establish casual relationships. Cross-cultural research can indicate whether certain aspects of development are universal or culturally influence.
• Experiments must be rigorously controlled as to be valid and replicable. Random assignments of participants can ensure validity.
• Laboratory experiments are easiest to control and replicate, but finding of field experiments may be more generalizable beyond the study situation. Natural experiments may be useful situations in which true experiments would be impractical or unethical.
• The two most common designs used to study age-related development are longitudinal and cross-sectional. Cross-sectional studies compare age groups; longitudinal studies describe continuity or change in the same participants. The sequential study is intended to overcome the weaknesses of the other two designs. A microgenetic study allows direct observation of change over a short period of time.

Guidepost 5 What ethical problems may arise in research on children?

• Ethical issues in research on child development involve the rights of participants to informed consent and avoidance of deception, protection from harm and loss of dignity, and guarantees of privacy and confidentiality.