Development is the scientific study of change over time across multiple domains, including physical and neurophysiological processes, language, cognition, emotion, personality, morality and our relationships with others. The field is also known as lifespan development, human developmental science or developmental psychology.
A common way to rate a country’s level of development is by its Gross National Income (GNI) per capita. This measure includes all the value of goods and services that a nation produces in a year, divided by its population. Developed countries tend to have much higher GNIs than developing ones.
One of the most important issues in development is eliminating poverty. Poverty prevents people from achieving many of the other goals of development, such as healthy living standards and access to education and health care.
Another issue in development is determining how much of a role a person plays in their own development. Some theorists, like Piaget or Erikson, assume that humans are active participants in their own development, while other theorists, such as behaviorists, view people as passive and at the mercy of their genetic inheritance and the environment in which they live.
Some theorists, such as Vygotsky and information processing theorists, assume that development is a continuous process. They believe that, as a person becomes more skilled in an activity, they acquire new capabilities through their interactions with other people and with the environment. Others, such as Amartya Sen and Martha Nussbaum, believe that development is a process of building the capacity to take advantage of opportunities and to deal with challenges.