Human development refers to the process of growth and change that individuals experience throughout their lives. This includes physical, cognitive, emotional, and social development, which are influenced by a combination of genetic factors and environmental conditions. Key stages of human development are often categorized into infancy, childhood, adolescence, adulthood, and old age. The study of human development is important for understanding how people evolve and adapt over time. It encompasses various theories, such as those proposed by Jean Piaget on cognitive development and Erik Erikson on psychosocial development. These frameworks help researchers and practitioners support individuals at different life stages.