Adult development is a research area that focuses on the psychological, social, and physical changes that individuals go through as they age from early adulthood to old age. This field explores how individuals continue to grow, change, and learn throughout their adult years. Researchers in adult development may study factors such as career development, relationships, health and well-being, and cognitive functioning in older adults. This area of study is important for understanding how individuals change and adapt across the lifespan, and how society can better support the needs of adults at different stages of life.