Variable Ratio Reinforcement

Biological Parallel

Woodpeckers hammer trees searching for beetle larvae—sometimes finding food after 3 pecks, sometimes 30, unpredictably. This variable ratio reinforcement creates persistent behavior resistant to extinction. Slot machines exploit this: evolved to persist through uncertain foraging, humans compulsively pull levers for random rewards. Predictable rewards create satiation; unpredictable rewards create addiction. The brain evolved to chase variance in patchy environments where giving up meant starvation.