उत्तर : 4. "a puzzle box"
व्याख्या :

Answer: D) a puzzle box Explanation: Edward Thorndike (1874 - 1949) is famous in psychology for his work on learning theory that lead to the development of operant conditioning within behaviorism. Thorndike (1898) studied learning in animals (usually cats). He devised a classic experiment in which he used a puzzle box to empirically test the laws of learning.