Child psychology is the study of human development with a focus on the childhood years and issues specific to this age group. The exact years considered childhood may vary. For this course, we will cover development from conception through adolescence.   In general, development examines patterns of growth, change, and stability by applying universal principles of development, including variations due to culture, race, ethnicity, and individual differences. The study of development investigates changes in the physical or biological, cognitive, and psychosocial of socioemotional domains, as well as the interactions between changes in these domains.

While we will be studying the period that we call childhood, it is important to remember that developmental age ranges are social constructs. People mature at different rates and reach milestones at various points; we most often refer to milestone averages, but some people will be above or below the average. Environmental factors also influence development. Variations in development may exist in different cultures. When we discuss developmental theories and milestones, we are discussing the average, typical, or trend that applies to the most significant segments of the population. Individual and cultural variations exist and do not necessitate abnormality or concern.

You will discover that no matter the age, domain, or topic of study, developmental psychologists consider several key questions. Is development continuous or discontinuous? Is development active or passive? Are there critical periods of development or only sensitive periods? Is development a result of nature or nurture? Does development vary due to cohort effects, sociocultural influences, and life events? In this chapter, we will explore these questions more in-depth.