A development is a growth, progress or positive change that involves a physical, economic, environmental and social aspect. Sustainable development is a global issue that includes the elimination of poverty, environmental degradation and the promotion of healthy and sustainable communities worldwide.
The most widely recognized indicator of development is gross national product (or GDP) per capita. However, this does not necessarily indicate whether a nation’s citizens have access to the most basic necessities such as clean air and water. Nations can also differ greatly in the way that they prioritize development, with some nations focusing more on industrial growth while others put a priority on addressing social issues such as crime, education and healthcare.
Many development theorists argue that the pace and scope of development varies according to the cultural and historical context in which it unfolds. Lifespan researchers, for example, believe that developmental processes are influenced by both biological and social factors.
Other theorists, such as Piaget and the various neo-constructivist theories that inspired him, believe that humans play an active role in their own development. These theorists posit that people construct new ways of thinking to explain their own experiences, which may help them adapt to changing circumstances and achieve certain developmental milestones.
Other theorists, such as mechanistic meta-theorists, compare human development to machine parts. These theorists see people as passive, with their growth based solely on the effects of external forces such as the environment. The most common metaphor is that of a car—people react to their surroundings like cars respond to their gas pedals or brakes.