Self-determination theory
People sustain effort when a task feels chosen, achievable and connected to others.
Motivation varies in kind, not only in amount. Behaviour driven by interest or personal value persists and generalises; behaviour driven by external pressure needs the pressure to stay on. Three conditions support the durable kind: autonomy, meaning the sense of choosing, competence, meaning the sense of getting better, and relatedness, meaning the sense of mattering to someone.
How it shows up in software
SDT is the usual diagnosis when engagement mechanics stop working. A user who has no real choices, cannot tell whether they are improving, and sees no one else in the product will churn: The rate at which customers stop paying or stop using the product. regardless of how many points you award. It is most useful as a checklist on an existing flow rather than as a feature to build.
Using it well
- Give real options at meaningful decision points, including the option to skip, and make skipping cost nothing.
- Show competence directly: what the user can do now that they could not do last week, in their own terms.
- Explain the reason behind any constraint you impose, since a justified rule reads as less controlling than an unexplained one.
- Audit your engagement surface by asking which of the three needs each element serves. Anything that serves none is decoration.
Where it turns manipulative
- Autonomy theatre, where the choices offered are cosmetic and the real decisions stay locked, is worse than offering no choice, because it invites the user to notice.
- Manufactured relatedness, like fake presence indicators or bot accounts that congratulate the user, borrows a real human need to move a number.
- Quoting SDT while shipping points and leaderboards is the most common form of this misuse. Those are controlling mechanics, and the theory predicts they will undercut the motivation you want.
Where you have seen it
Duolingo
Users pick a daily goal size and can change it, which places the intensity of the commitment with the learner.
Strava
Segment leaderboards sit next to personal-best tracking, so a user can measure against others or only against themselves.
What the research says
- Deci and Ryan, 1985Well evidenced
Set out the theory and the distinction between intrinsic motivation and the varieties of extrinsic regulation.
- Ryan and Deci, 2000Mixed evidence
Consolidated decades of work linking the three needs to persistence, wellbeing and performance across education, work and health.
The framework is well supported and heavily cited. Much of the supporting work is self-report and cross-sectional, and the claim that the three needs are universal and basic remains argued over across cultures.
Grades are a judgement about the evidence, not about how useful the idea is. Plenty of contested effects are still worth knowing, as long as you do not cite them as settled.