Self-Determination Theory (SDT) was developed by researchers Edward L. Deci and Richard M. Ryan. This theory concerns with human motivation, personality and optimal functioning. Rather than just the amount of motivation, self-determination theory focuses on different types of motivation.
Since positive psychology deals with positive emotions and ways to nurture individual’s strengths, SDT is useful in merging a good amount of work in positive psychology.
SDT claims that people have three innate psychological needs which are considered as universal necessities. SDT also asserts that there are different approaches to motivation, and differentiates between different types of motivation