Human development is an intricate lifelong process beginning before birth and extending to death; however, the common bond all humans have is basic life stages from birth to death. At each moment in life, every human being is in a state of personal evolution. Though no two human beings will have the same life experiences, there are certain predictable patterns that occur and are common to most everyone. How a person develops throughout their life depends on a blending of environmental experiences and biology. Nature and nurture intertwined even before we are born. Physical changes largely drive the process, as our cognitive abilities advance and decline in response to the brain's growth in childhood and reduced function in old age. Psychosocial development is also significantly influenced by physical growth, as our changing body and brain, together with our environment, shape our identity and our relationships with other people. As human beings progress from infancy to childhood to adolescence and then to adulthood, motor skills, imagination, desires and other thought processes become more refined and complex. Several theorists have attempted to identify the stages of cognitive and physical development, and in the process, have changed the way we think about the human body and mind. .
Development is the series of age-related changes that happen over the course of a life span. The three areas of human development are physical, cognitive and social-emotional. These areas are different in many ways, but they also influence one another. At each stage of development, specific physical changes occur that affect the individual's cognitive and psychosocial development. For example physical development (e.g., neurological growth) allows cognitive advancements to take place, and increases in the ability to look at situations from multiple perspectives (a cognitive ability) make possible more effective in creating social relationships.