Edward L. Thorndike (1874-1949) was a pioneer in the experimental study of animal learning whose work laid the groundwork for behaviorism and modern learning theory. His puzzle box experiments with cats — in which hungry cats learned through trial and error to operate latches and escape from boxes to reach food — led to the formulation of fundamental learning principles that remain central to psychology and education.
The Law of Effect
Thorndike's most important contribution, the law of effect, states that responses followed by satisfying consequences are "stamped in" (strengthened), while responses followed by annoying consequences are "stamped out" (weakened). This principle anticipated operant conditioning (Skinner) and remains the foundation of reinforcement-based learning. Thorndike's learning curves showed that learning was gradual and incremental rather than sudden, with errors decreasing progressively over trials — characterizing learning as the strengthening of stimulus-response connections.
Thorndike was also a founder of educational psychology. His laws of exercise (practice strengthens connections), readiness (learning is most effective when the organism is prepared), and identical elements (transfer depends on similarity between training and test situations) influenced educational practice for decades. His research on transfer of training debunked the popular "formal discipline" theory (that studying Latin or geometry strengthened the mind generally), showing instead that transfer is specific to shared elements between tasks — a finding confirmed by modern transfer research.