Variable Reward(Variable Reward)

A reinforcement pattern in which behavior is sustained most strongly when rewards are delivered on an unpredictable schedule. B.F. Skinner’s operant conditioning research demonstrated that variable-ratio reinforcement schedules produce greater behavioral persistence than fixed-ratio schedules, even with fewer total rewards.

Slot machines, social media notifications, and gacha mechanics all exploit this schedule. Because the timing of the next reward cannot be predicted, the psychological cost of stopping rises continuously — making disengagement harder the longer the streak continues.