Final answer:
Thorndike's law of effect states that pleasant behaviors are reinforced, making them more likely to be repeated, which is fundamental to the concept of operant conditioning.
Step-by-step explanation:
According to Thorndike's law of effect, behaviors followed by satisfying consequences are more likely to be repeated. In this context, when a behavior is pleasant, it is 1) Reinforced. This principle laid the foundation for B.F. Skinner's work on operant conditioning, which expands on the idea by applying reinforcement or punishment to either strengthen or weaken a behavior. Reinforcement can be positive or negative, but both forms aim to increase the likelihood of the behavior being repeated in the future.