What does developmental psychology primarily study?

Developmental psychology primarily focuses on how individuals grow and change throughout their lifespan. This field examines the psychological, emotional, cognitive, and social development from infancy through old age. Developmental psychologists study various factors that influence development, including biological, environmental, and cultural influences. They analyze milestones such as language acquisition, motor skills, and social interactions, along with how these elements evolve and impact individuals over time.

The other options, while related to specific aspects of human behavior and psychology, do not capture the comprehensive scope of developmental psychology. For instance, studying interactions in social settings pertains more to social psychology. The impact of genetics on personality is primarily the domain of behavioral genetics, and understanding the effects of trauma on behavior is typically explored within clinical psychology or trauma psychology. These areas provide valuable insights into human behavior but do not embody the overarching goal of exploring developmental changes throughout a person's life, which is central to developmental psychology.