Motivation is the reason for people’s actions, desires, and needs….and can be divided into two different theories known as intrinsic (internal or inherent) motivation and extrinsic (external) motivation. Wikipedia.
Intrinsic motivation is the natural, inherent drive to seek out challenges and new possibilities that Self-determination theory (SDT) associates with cognitive and social development
Extrinsic motivation comes from external sources – from influences outside of the individual. Your boss/spouse/children/parents. Society norms. Your peer group.
Here Dan Pink examines the puzzle of motivation