Vallerand & Reid (1984), Journal of Sport Psychology (N=115/84) — positive feedback INCREASES while negative feedback DECREASES intrinsic motivation; perceived competence MEDIATES

Claim: Vallerand & Reid (1984), "On the causal effects of perceived competence on intrinsic motivation: A test of cognitive evaluation theory," Journal of Sport Psychology 6, 94-102 (N=115 phase 1; 84 returned). One-way ANOVA showed "positive feedback increased while negative feedback decreased both intrinsic motivation and perceived competence," and path analysis "supported the mediating effects of perceived competence on intrinsic motivation."

Source: Vallerand & Reid (1984), Journal of Sport Psychology.

Confidence: Verified.

Why this matters for Candid: Settles the contextual-feedback design question for tools. A tool that makes the user feel effective (clean inputs → clear positive output) multiplies the engagement effect; a confusing or error-pronouncing tool inverts it. Mediation through perceived competence is the operational lever.