insufficient justification effect
the finding that in some situations people are more likely to undertake a task that goes against their character or personal beliefs when offered a small reward versus a larger reward, and similarly more likely to decline a desired activity when presented with a mild threat versus a more serious threat. For example, in a classic 1959 study by psychologists Leon Festinger and James M. Carlsmith, participants were offered money to lie about their interest in a particular task: Those who received $1 were more motivated to lie than those who received $20. The theory is that when extrinsic motivation is low, people are motivated to reduce the cognitive dissonance they experience by finding an intrinsic motivation for their behavior (e.g., by telling themselves they had no wish to break that particular rule anyway). Compare overjustification effect.