Original: This field examines change across a broad range of topics including motor skills and other psycho-physiological processes; cognitive development involving areas such as problem solving, moral understanding, and conceptual understanding; language acquisition; social, personality, and emotional development; and self-concept and identity formation.
Simplified: Developmental psychology studies human change in a lot of areas, including motor skills (and other processes that are both physical and psychological), problem solving abilities, understanding of concepts, learning language, moral understanding, and identity.