How do we explain behaviour? What motivates us to do certain things?
In the 1970s psychologists explored the interplay between our self-driven (or 'intrinsic') motivation and outside influences ('extrinsic motivation'), and a 1971 experiment by Edward L. Deci highlighted the so-called undermining effect: if you provide incentives for someone to carry out an activity they already enjoy, it undermines their original reason for doing it.
In a typical experiment two randomly split groups of participants are asked to perform an interesting task – but only one of the groups are told they will be paid as a reward if they perform well. Later on, participants are asked to choose a task without any reward. Participants from the reward group are less likely to pick up the same task if they cease to be rewarded for the performance. In other words, the payment has undermined their intrinsic motivation.
Research on motivation and the undermining effect later grew into the self-determination theory, which has influenced motivational practices across wide parts of society - including areas such as business, education and sport.