Technique · Influence
Minimum effective incentive
For behaviors you want users to own, use the smallest incentive that still gets the behavior, announce up front when any launch bonus ends, and favor recognition over payment. Large rewards and threats buy compliance only while they last; small ones leave room for people to feel they chose.
Plain label: smallest reward that still worksAlso known as: barely sufficient reason, inner choice, overjustification, incentive fade-out
How it works
People take inner responsibility for an act only when they believe they chose it without strong outside pressure. Heavy rewards or threats give them an outside reason, so the behavior stops when the reward or threat does; a mild reason leads them to explain the act to themselves, and the behavior persists unobserved. Stepping incentives down while measuring activity after they end shows how much of the behavior users own.
In the book. Inner choice outweighs the other commitment properties, and the mildest push that still gets the behavior builds the most lasting change (Ch.3, pp.70-74). A promised reward that was canceled left energy savers saving more, because the only outside reason was gone (Ch.3, pp.77-79). INF-T-CC-23 (Influence Ch.3, p.71) INF-T-CC-25 (Influence Ch.3, p.77)
In a product [S]. Step incentives down, announce fade-outs in advance, and measure what remains afterward.
Evidence Evidence grade B. Moderate evidence: solid studies with some limits.. The undermining effect of expected rewards is well studied, though its size is debated.
Evidence warning
Do not take away rewards users already receive unless something better replaces them; let only pre-announced launch incentives lapse.
What the research says
Boys warned off a toy robot with a severe threat or a mild request both complied at first; six weeks later, unobserved, 77% of the threatened boys played with it, against 33% of those mildly asked.
Influence Ch.3, pp.72-74 (Freedman), 1965
A meta-analysis of 128 experiments found that expected, tangible rewards reduced intrinsic motivation for interesting tasks.
Deci, Koestner & Ryan, Psychological Bulletin, 1999
Before you start
- An incentive currently attached to a core behavior (cash back, points, bonus credits)
How to build it
- Web
- Test the incentive downward (20% credit, 10%, then none plus a badge) and keep the smallest level whose post-incentive retention matches the larger ones.
- Mobile
- Announce at launch that bonus points apply only for the first 14 days; afterwards, celebrate the user's own progress rather than the points.
- B2B
- Replace large cash referral bounties with recognition and product credit, and read referral quality, not only volume.
What can go wrong
- Removing a reward people were promised or already enjoy.
- Threat-based retention (streak loss, account locks) for core behaviors.
- Stepping down so far that the behavior stops before users own it.
Pairs well with
- Pairs with HK-RWD28: small cash rewards can backfire.
- Pairs with in-t-cc-09: the user's own goal is the reason that remains.
Limits
What we don’t claim
- Left Brain and Right Brain are a metaphor for extrinsic and intrinsic motivation, not a claim about neuroscience.Actionable Gamification Ch.13, pp.342-343
Sources
Influence · Robert Cialdini
Ch.3, p.71 · Ch.3, p.77
A meta-analytic review of experiments examining the effects of extrinsic rewards on intrinsic motivation · Psychological Bulletin, 1999
Evidence grade B. Moderate evidence: solid studies with some limits.
Source IDs: INF-T-CC-23INF-T-CC-25
Book content is paraphrased, never quoted at length. Last verified October 24, 2026.
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