Development is the process of improvement in a nation’s economic, social and environmental well-being. Countries work toward development by eradicating poverty, hunger and disease and providing education, shelter and employment. This is accomplished by sustained economic growth, as measured by gross domestic product (GDP) per capita and other indicators like literacy rates, life expectancy and standard of living. Development also includes reducing carbon emissions, and protecting the environment.
Human development, also known as lifespan development or developmental science, is the scientific study of changes and stability across multiple domains of human functioning — physical and neurophysiological processes, cognition, language, personality, emotion, morality, and psychosocial development. It is a broad field, with many different theories and approaches.
There are different assumptions about what causes development, including whether it is purely genetic or biological or the result of nurture (environment and learning). Some researchers, called lifespan theorists, believe that development is a multidirectional, nonlinear process. Others, called ecological systems theorists, believe that development takes on a variety of patterns and pathways, depending on the cultural, historical, and societal context in which it unfolds.
Some development theorists, such as Piaget and Kohlberg, use a butterfly metaphor to describe their theories of cognitive development. They believe that people develop through discontinuous qualitatively different stages, just as the caterpillar changes into a chrysalis and then into a butterfly. Other theorists, such as behaviorism and mechanistic meta-theories, view humans as passive participants in their own development, responding to forces that control them — like a car reacting to its gas pedal or brake.