C22 Tangible rewards and interest
alive 1 attack: 1 survived · serves Q1 · last change 6 November 2026
Promising people a tangible reward (such as money or a prize) simply for doing an activity they already find interesting makes them choose to do it less on their own once the reward stops, by roughly 0.2 to 0.4 standard deviations compared with no reward, and children are hit at least as hard as adults.
In practice
Promising a tangible reward (money or a prize) for doing an activity people already find interesting can make them choose it less once the reward stops. Even Cameron, Banko & Pierce's 2001 counter-meta — arguing that pervasive reward harm is a myth — found expected tangible rewards on high-interest tasks lowered later free-choice (d1 = −0.18), and rewards offered for doing the task lowered it further (d1 = −0.35 across 57 studies; −0.30 with outliers removed). Deci, Koestner & Ryan 1999 (abstract) reported similar free-choice drops under engagement-, completion- and performance-contingent rewards (d = −0.40, −0.36, −0.28); their 2001 full report (Table 1) shows rewards for simply doing the task hit children harder (d = −0.43) than college students (d = −0.21), completion-contingent free-choice d = −0.44, and performance-contingent rewards that were not maximal d = −0.88 versus −0.15 when maximal.
Go deeper
Where it holds
Main limits
- About expected tangible rewards for doing interesting activities and later free-choice engagement, not grades or task feedback (C4) and not growth-mindset lessons (C13).
- When rewards are tightly tied to meeting a score or exceeding others, Cameron et al. 2001 found free-choice unchanged or higher — do not treat every prize the same; but pay per unit solved lowered later free choice when people earned less than the maximum (d1 = −0.22, 14 studies; Murayama et al. 2010 consistent in a small lab test).
- Cameron & Pierce 1994 (abstract) found no overall reward harm.
- Lab tasks; outcome is motivation, not learning.
- Measured soon after the reward stops: in the few studies that checked again weeks later, the drop had mostly faded (2 of 7 still significant; Cameron et al. 2001).
All limits (12)
Inside the circle: the core of the claim. Outside: every bound and carve-out in the claim file, numbered, with the attack that forced or added it where the record shows one.
forced by a narrowing attackin the original wordingwritten at creation, or added without a narrowing
Warm cards in the list were added by later attacks; plain cards were in the original draft or written at creation.
Expected tangible rewards for activities people already find interesting, with later free-choice engagement as the outcome; not grades or task-process feedback (C4) and not short growth-mindset lessons (C13).
Written when the claim was created (27 October 2026); not forced by an attack
Evidence on file: Deci, Koestner & Ryan 1999 (Psychological Bulletin 125(6), 627–668, DOI 10.1037/0033-2909.125.6.627; abstract): meta of 128 experiments; free-choice intrinsic motivation undermined by engagement-contingent (d = −0.40), completion-contingent (d = −0.36) and performance-contingent rewards (d = −0.28); tangible and expected rewards harmed; worse for children than college students; positive feedback enhanced free-choice (d = 0.33).
Written when the claim was created (27 October 2026); not forced by an attack
Cameron & Pierce 1994 (Review of Educational Research 64(3), 363–423, DOI 10.3102/00346543064003363; abstract): 96 between-groups experiments; overall reward did not decrease intrinsic motivation; the only negative effect was expected tangible rewards given simply for doing a task (minimal); verbal praise increased motivation.
Written when the claim was created (27 October 2026); not forced by an attack
Kill-test survived 2026-10-27: Cameron, Banko & Pierce 2001 (The Behavior Analyst 24(1), 1–44, DOI 10.1007/BF03392017; full text): even this counter-meta found expected tangible rewards on high-interest tasks lowered free-choice (d1 = −0.18, CI −0.23 to −0.13) and rewards offered for doing the task lowered it further (all 57 studies d1 = −0.35, CI −0.43 to −0.27, not homogeneous; with outliers removed d+ = −0.30, CI −0.38 to −0.22, K = 50, N = 2,642; Figure 1, p. 17; precision corrected 2026-10-30); free-choice was unchanged or higher when rewards were tied to meeting a score or exceeding others — a contingency carve-out, not a kill of the claim's "for doing" wording.
Added with attack #1 (survived; it did not narrow the claim) · Cameron, Banko & Pierce 2001 · 27 October 2026
Wording changed later: Added with attack #4 (corrected; it did not narrow the claim) · Cameron, Banko & Pierce 2001 · 30 October 2026.
The same meta's carve-out is narrower than it looks for pay per unit solved (corrected 2026-10-28; full text pp. 19–20): when people could earn the maximum, free-choice was unchanged (K = 6, N = 345, d1 = −0.03, CI −0.25 to 0.18), but when they earned less than the maximum it fell (K = 14, N = 749, d1 = −0.22, CI −0.37 to −0.07); the authors conclude the negative effect of pay per unit goes with receiving less than the maximum reward.
Added with attack #2 (corrected; it did not narrow the claim) · Cameron, Banko & Pierce 2001 · 28 October 2026
Murayama, Matsumoto, Izuma & Matsumoto 2010 (PNAS 107(49), 20911–20916, DOI 10.1073/pnas.1013305107; PMC full text; n = 28) is consistent: ¥200 per successful trial on an interesting stopwatch task, against yoked equal pay, cut voluntary plays in 3-minute free-choice periods after the reward stopped (F(1,26) = 6.59, P = .016) — a small, non-preregistered lab test, support only, not a kill-condition trial.
Added with attack #2 (corrected; it did not narrow the claim) · Cameron, Banko & Pierce 2001 · 28 October 2026
Durability (added 2026-10-30): of seven experiments with rewards for doing the task that measured free choice again a few weeks later, only two still showed a significant drop (Cameron et al. 2001, pp. 23–24); the drop C22 describes is measured in a free-choice period soon after the reward stops, and whether it lasts is open (open question 19).
Added with attack #4 (corrected; it did not narrow the claim) · Cameron, Banko & Pierce 2001 · 30 October 2026
Bitter, Wondra, McCrea, Darzi & Novak 2022 (Technology, Mind, and Behavior 3(1), 39–56, DOI 10.1037/tmb0000056; full text; added 2026-10-30): two preregistered online 2 × 2 experiments with US crowd-workers (N = 441 and 1,105; mean age about 40) on a location-memory task; removing pay of 1–3 cents per correct response lowered free-choice attempts and performance minutes later (pooled over both studies d = .19, 95% CI .05 to .34, and d = .22, .08 to .36; Study 2 alone .17 and .16) — consistent with the bottom of the range for adults, but the pay was per correct response (performance-contingent), not simply for doing, so it is support and not a kill-condition test.
Added with attack #4 (corrected; it did not narrow the claim) · Cameron, Banko & Pierce 2001 · 30 October 2026
Child–adult prong (corrected 2026-10-30; contingency enrichment 2026-11-06): now read in full text in Deci, Koestner & Ryan 2001 (Review of Educational Research 71(1), 1–27, DOI 10.3102/00346543071001001; Table 1, the same meta-analytic data as Deci et al. 1999): rewards given simply for engaging in the task lowered free choice more in children (d = −0.43, k = 39) than in college students (d = −0.21, k = 12), and the authors report the difference as significant; for tangible rewards overall the undermining was significantly greater for children on both free-choice and self-report measures.
Added with attack #4 (corrected; it did not narrow the claim) · Cameron, Banko & Pierce 2001 · 30 October 2026
The same Table 1: completion-contingent free-choice d = −0.44 (k = 19); performance-contingent free-choice d = −0.28 (k = 32), of which maximal reward d = −0.15 (k = 18) and not-maximum reward d = −0.88 (k = 6).
Added with attack #5 (corrected; it did not narrow the claim) · Deci, Koestner & Ryan 2001 · 6 November 2026
Cameron et al. 2001 tried age as a moderator for rewards for doing the task and could not resolve it (p. 17).
Added with attack #4 (corrected; it did not narrow the claim) · Cameron, Banko & Pierce 2001 · 30 October 2026
Deci 1999 and Cameron & Pierce 1994 remain abstract-only; Deci et al. 2001, Cameron et al. 2001 and Bitter et al. 2022 are full text.
Added with attack #1 (survived; it did not narrow the claim) · Cameron, Banko & Pierce 2001 · 27 October 2026
Wording changed later: Added with attack #4 (corrected; it did not narrow the claim) · Cameron, Banko & Pierce 2001 · 30 October 2026.
0 of 12 bounds and carve-outs were forced by a specific attack. 1 attack hit the boundary and did not move it: #1.
How it changed
The ledger records 1 attack (and 4 corrections to our notes), but no earlier wording of C22 is on record, so the text cannot be replayed step by step. Only the current wording is shown.
Promising people a tangible reward (such as money or a prize) simply for doing an activity they already find interesting makes them choose to do it less on their own once the reward stops, by roughly 0.2 to 0.4 standard deviations compared with no reward, and children are hit at least as hard as adults.
What would change this
What would kill it: A large preregistered experiment or meta-analysis finds that expected tangible rewards for doing an interesting task leave later free-choice engagement unchanged or higher than with no reward. Sharpened 2026-10-29 (bold expansion): the claim also dies if such a test finds the drop smaller than about 0.1 standard deviations, or larger in adults than in children. Added as a claim on 27 October 2026, promoted from a candidate belief in the evidence library. Area: Motivation and curiosity (second claim after C13).
Attack record
1 attack: 1 survived. Counts of attacks, not a score.
Full attack list (1)
A large meta-analysis would meet C22's kill-condition if expected tangible rewards for doing an interesting task left later free-choice engagement unchanged or higher than with no reward; Cameron, Banko & Pierce 2001 — the main counter-meta arguing that pervasive reward harm is a myth — still found free-choice d1 = −0.18 (95% CI −0.23, −0.13) for expected tangible rewards on high-interest tasks, and d1 = −0.35 (CI −0.43, −0.27; K = 57) when the reward was offered for doing the task.
Strongest reading and verdict reasoning
Steelmans to: C22 dies on a large meta that finds expected tangible rewards for interesting tasks leave later free-choice unchanged or higher; this is the strongest published counter-analysis to Deci et al. 1999, and the kill fails on its own free-choice numbers for expected tangible / doing.
Why: Extra12 attack pass 2026-10-27 Europe/Stockholm (parent: C22 never-targeted first honest OA attacks; C14 only if NEW OA; leave C19/C21). Full text read and stored (behavior.org OA PDF of Behavior Analyst 24:1–44; same as PMC2731358). Table 2 free-choice high-interest: expected tangible d1 = −0.18*; for doing a task (Figure 1 / text) d1 = −0.35* (K = 57, N = 2,910). Kill fails. Authors also report ns/positive free-choice for performance-criterion contingencies (meet a score; exceed others) — logged in Bounds as a contingency carve-out, not a weaken of the claim's "for doing an activity" wording. Not a restatement of Cameron & Pierce 1994 abstract in Bounds (different paper, full-text contingency split, now a kill-test). Not a preprint. Claim sentence and Status unchanged (alive). C22 now 1 of 3 survivals.
Corrections to our notes
These fix a number or a fact in our notes. They are not attacks and do not count toward the floor of 3 survivals.
- — C22's limits present Cameron, Banko & Pierce 2001's contingency carve-out (score- or competition-tied rewards leave free-choice unchanged or higher) without the same meta's per-unit result: when people were paid per unit solved and earned less than the maximum, free-choice fell (d1 = −0.22, K = 14), and Murayama et al. 2010 shows the same in a small randomised lab test.
Details
What was checked: fact behind the Bounds carve-out sentence (Cameron et al. 2001, pay per unit, maximum vs less than maximum reward); the 2026-10-27 survival entry stays as written.
Why: Nightly-attacks 2026-10-28 Europe/Stockholm, from a closer reading of the study (the run notes), re-checked tonight in the stored full text (pp. 19–20): "When rewards were offered for each unit solved, the findings showed nonsignificant effects for studies of maximum rewards (K = 6, N = 345, d1 = −0.03, CI = −0.25, 0.18) and a significant negative effect for studies of less than maximum reward (K = 14, N = 749, d1 = −0.22, CI = −0.37, −0.07)... the negative effect of pay per unit is associated with participants receiving less than maximum rewards." Murayama et al. 2010 (n = 28; ¥200 per successful stopwatch trial vs yoked equal pay; free-choice plays fewer in the reward group, F(1,26) = 6.59, P = .016) is consistent; it is small and not preregistered, so it is cited as support, not as a kill-condition trial (as decided 2026-10-27 extra13). Not a weaken: the claim's "for doing an activity" scope, direction and kill-condition are unchanged; the correction makes the carve-out more precise. Not a survival; does not count toward the floor.
- — Wording change only, not an attack: a vague claim sentence was made sharper, so that real counter-evidence can kill it.
Details
What was checked: none (wording only; no new study, no survival, no streak reset).
Why: the claim named no size; it now gives the range already on file (Cameron, Banko & Pierce 2001 d1 = −0.18 for expected tangible rewards on high-interest tasks and −0.35 for doing the task; Deci, Koestner & Ryan 1999 d = −0.28 to −0.40, worse for children than college students). The claim is made bolder, not narrower; Status and Bounds unchanged; a matching kill line was added. Counts as neither an attack nor a survival under the project's attack rules (corrected is not a survival).
- — Checked against the full text of the study: precision of the Cameron et al. 2001 "for doing the task" estimate.
Details
What was checked: precision of the Cameron et al. 2001 "for doing the task" estimate; the evidence behind "children are hit at least as hard as adults"; time span of the drop. No kill-condition test (Bitter et al. 2022 was considered as one and not counted; see Why).
Why: Nightly-attacks 2026-10-30 Europe/Stockholm. (1) Cameron et al. 2001 p. 17: "for doing a task... (K = 57, N = 2,910, d+ = −0.35, CI = −0.43, −0.27) but not homogeneous"; Figure 1 (homogeneous samples): for doing task K = 50, N = 2,642, d+ = −0.30** (−0.38, −0.22). Both now in Bounds. (2) Durability, pp. 23–24: "Only two of the seven studies showed a significant negative effect on the second measure" a few weeks later; recorded as a time limit in Bounds, held as open question 19 (added by mining), not a narrowing: C22 does not assert a lasting drop. (3) Bitter et al. 2022, p. 52: "removing pay had robust effects on both number attempted, d = .19, 95% CI = [.05, .34], and performance, d = .22, 95% CI = [.08, .36]"; preregistered, N = 441 and 1,105 adults; pay was 1–3 cents per correct n-back response. Routed as a trial and rejected as survive-and-log: performance-contingent per-correct pay is not the "simply for doing" contingency C22 asserts, so a survival would not be an equal trial; logged as adult support at the bottom of the range. (4) Deci et al. 2001, Table 1 and pp. 9–10: engagement-contingent free choice, college d = −0.21* (k = 12), children d = −0.43* (k = 39); "the undermining on the free-choice measure, while significant for both children and college students, was significantly stronger for children than for college students"; tangible rewards overall: "the undermining effect was significantly greater for children than for college students on both behavioral and self-report measures". The prong no longer rests on an abstract. Claim text, Status and kill-condition unchanged. Not a survival; does not count toward the floor. Internal note: the 2026-10-28 record's per-unit "0.19" was the task-interest figure; free-choice per unit is d+ = −0.16 (K = 20); public pages never carried it.
- — Checked against the full text of the study: contingency detail in Deci et al. 2001 Table 1 beyond the child–adult engagement split already on file.
Details
What was checked: contingency detail in Deci et al. 2001 Table 1 beyond the child–adult engagement split already on file; no kill-condition test.
Why: Nightly-attacks 2026-11-06 Europe/Stockholm (the targeting rules queue). Full text Table 1: completion-contingent free-choice d = −0.44* (k = 19); performance-contingent free-choice d = −0.28* (k = 32), maximal reward −0.15* (k = 18), not-maximum −0.88* (k = 6). Child–adult engagement figures (−0.43 / −0.21) and tangible overall −0.34 confirmed (already in Bounds from). Not a duplicate of Cameron et al. 2001's max vs less-than-maximum per-unit carve-out (different meta, different contingency coding); not a restatement of the Deci 1999 abstract line (completion −0.36 there). Supports C22 on all kill prongs; not a kill. Claim text, Status and kill line unchanged. Not a survival; does not count toward the floor; does not reset C22's fruitless streak. C22 returns from rest under the targeting rules(a) on this verified full-text 3g flag.
Evidence
6 linked sources: 5 supports, 1 limits, 1 challenges (first-pass draft, pending human review). supports: Deci et al. 1999, Cameron & Pierce 1994, Murayama et al. 2010, Bitter et al. 2022, Deci et al. 2001 · limits: Cameron et al. 2001 · challenges: Cameron et al. 2001