Scenario: An employee consistently meets all performance targets but discovers that a coworker who achieves 20% less overall output receives the exact same annual performance bonus. Feeling under-rewarded and unappreciated, the employee intentionally reduces their work effort and productivity to align with their perceived level of compensation fairness. This behavioral response is best explained by which motivational theory?

Formulated by J. Stacy Adams, Equity Theory posits that individuals evaluate fairness in the workplace by comparing their ratio of Inputs (effort, time, skills, experience) to Outcomes (salary, bonuses, recognition) against the input-outcome ratio of a relevant comparison peer. When an employee perceives inequity (under-reward), it produces psychological tension and cognitive dissonance. To eliminate this distress and restore equity, the individual adopts behavioral mechanisms—most commonly by reducing inputs (lowering performance, reducing effort, or showing up late) so that their ratio balances with the referent peer.