Developmental psychology explores the changes and continuities in human abilities throughout life, encompassing physical, cognitive, linguistic, and social dimensions. Human development is not restricted to growth, but includes aspects of decline, particularly in physical abilities as individuals age. Developmental psychologists seek to understand how people change as they age and how their mental and social skills evolve.

Developmental Milestones

A key concept in developmental psychology is developmental milestones, which serve as benchmarks for evaluating the typical progression of abilities in children. These milestones are age-related norms used to compare children with peers of the same age group. For instance, typical physical milestones include crawling, walking, and writing, while cognitive and linguistic milestones involve naming colors and speaking in sentences. Developmental milestones help professionals and caregivers assess whether a child's development is progressing as expected.

Biological vs. Social Milestones

Developmental milestones are categorized into biological and social types. Biological milestones, such as puberty, follow a relatively universal timeline across different cultures, indicating a shared biological foundation. In contrast, social milestones, like the age at which children begin formal education, are more variable and influenced by cultural and socio-economic factors. For example, in many developed countries, such as the United States, children start school around the age of 5 or 6. However, in some developing countries, such as Nigeria, children may enter formal education at a later age, reflecting differences in cultural practices and educational infrastructure.