What is the focus of developmental psychology?

Developmental psychology primarily centers on understanding how individuals grow and change throughout their lifespan. This field examines various aspects of development, including cognitive, emotional, social, and physical growth from infancy through old age. Researchers in developmental psychology seek to understand the patterns and stages of development, how different experiences, environments, and biology influence development, and how individuals adapt to changes over time.

While the other options touch on important aspects of psychology, they do not encapsulate the broad scope of developmental psychology. The study of cultural differences, for example, is significant but more aligned with cultural psychology. Similarly, analyzing social interactions across age groups is important, but it falls under social psychology rather than being the primary focus of developmental psychology. Finally, the examination of mental disorders and their treatments pertains to clinical psychology rather than the holistic development and changes that individuals experience throughout their lives. Thus, the correct choice reflects the foundational aim of developmental psychology itself, which is to chart the course of human growth and change over time.