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Social loafing is the tendency to exert less effort on a task when working as part of a group than when working alone. The effect is well-documented, surprisingly consistent across contexts, and deeply familiar to anyone who has survived a frustrating group project. Psychologists have studied it since the 1880s, and what they’ve found goes well beyond laziness — social...

The overjustification effect occurs when offering an external reward for an activity someone already enjoys causes their intrinsic motivation to decline — sometimes called the undermining effect for exactly this reason. First demonstrated in Deci’s early laboratory work and later confirmed in Lepper, Greene, and Nisbett’s landmark 1973 study, overjustification effect psycholo...

Goal setting theory, developed by Edwin Locke and expanded with Gary Latham, proposes that specific, challenging goals — paired with adequate feedback — consistently produce better performance than vague or easy targets. First articulated by Locke in the 1960s and formalized in their landmark 1990 framework, the theory has become one of the most empirically supported models i...

Cialdini’s principles of persuasion are six psychological triggers that explain why people comply with requests, change their minds, or make purchases they hadn’t planned on. Identified by social psychologist Robert Cialdini in his landmark 1984 book Influence, these principles are grounded in universal human tendencies — cognitive shortcuts that make everyday decision-making...