Self-Determination Theory (SDT) — Deci & Ryan's 50-year research, the 3 basic needs of autonomy / competence / relatedness, and the "overjustification effect" of external rewards killing intrinsic motivation

1. The start of SDT — the 1971 Soma Cube experiment

Deci's 1971 dissertation experiment. College students in 2 groups solved Soma cube puzzles:

• Group A: stage 1 (free time), stage 2 ($1 reward per puzzle), stage 3 (free time again)
• Group B: no reward at any stage

Result: Group A solved fewer puzzles in stage 3 (after rewards stopped) — "reward kills intrinsic interest". Group B kept interest. The "Overjustification Effect" was discovered.

2. 3 basic psychological needs

① Autonomy

• Own choice, exercising will
• Sense of "I decide"
• No coercion / control
• Understanding reasons

② Competence

• Sense of "I can do this"
• Challenge + growth available
• Not too easy, not too hard (Flow)
• Appropriate feedback

③ Relatedness

• Sense of "I belong"
• Close, authentic connection
• Safe relationships
• Meaningful contribution

The 3 needs are as "basic" as food and sleep — unmet, mental health is damaged.

3. Intrinsic vs extrinsic motivation spectrum

SDT's aim: gradually move behavior from "extrinsic" to "intrinsic".

4. The Overjustification Effect

Adding external reward to an activity already done from intrinsic motivation → intrinsic motivation "decreases". Mechanism: shift in perception to "I do this because of the reward, not because I like it".

Famous examples:

• Lepper 1973: children who loved drawing got sticker rewards for drawing → they learned "no sticker, no drawing"
• Glucksberg 1962: reward groups showed lower creative problem solving
• Smoking-cessation reward programs: short-term effective; long-term less so (extrinsic only)

5. Korea's external-motivation culture

• School: tests, grades, ranks
• University: entrance exams, GPA, employment
• Workplace: salary, promotion, evaluations
• Family: parental expectations, face, comparison
• SNS: likes, followers

Result: 60% of Korean youth "don't know why I'm living" (Korea Youth Policy Institute 2022); no opportunity for intrinsic-motivation development; explosion of burnout and depression.

6. Data: Korea ranks low in self-determination at the OECD

OECD 2020 "How's Life" autonomy perception:

Korea's self-determination is near the OECD bottom. Strongly correlated with depression / suicide / burnout data.

7. 5 behaviors of Autonomy Support

Applicable to parents, teachers, managers, partners:

1. Offer choices: "~ or ~ — your choice"
2. Explain reasons: tell them "why" (not "do it because I said so")
3. Empathic acknowledgment: "I understand how you feel"
4. No controlling language: "have to" → "can" / "what do you think?"
5. Allow mistakes / emphasize learning: not evaluation, value the process

8. Korean application examples

Child-rearing

• "Study" → "what do you want to study today?" — discuss why studying matters
• No forced cram school → "this academy vs that academy or none" choice
• No grade comparison → compare to their self of a year ago
• Not "why did you do that" on mistakes → "what did you learn?"

Workplace management

• No micromanaging → clear outcomes, process autonomy
• Share company strategy "why we do this"
• No punishment on mistakes → learning rituals (#263)
• Flexible work (time, place) raises autonomy where possible

Your own self-determination

• Ask "why" about work / hobbies / relationships
• If 70%+ extrinsic motivation (money / face), it's a crisis signal
• Gradually shift to "identified" motivation
• Integrate values work (#265 ACT)

9. Clinical effects — 1,000+ meta-analyses

Ryan & Deci (2017) "Self-Determination Theory" book meta-analysis synthesis:

10. Korean resources

• Korean Society for Self-Determination Theory
• "Why We Do What We Do" (Deci, Korean edition)
• SDT labs at some universities (SNU, Yonsei)
• SDT integration is increasing in education / counseling / coaching
• Application to family / couples therapy