Which scenario exemplifies operant conditioning?

The scenario in which a child learns to say thank you after receiving praise perfectly exemplifies operant conditioning. Operant conditioning is a learning process in which behavior is determined by the consequences that follow it. In this case, the child receives positive reinforcement (praise) for the behavior of saying thank you, which increases the likelihood that the child will repeat this behavior in the future. The association between the action (saying thank you) and the pleasant outcome (praise) promotes the learning and maintenance of the behavior.

In the other scenarios, while learning is occurring, they do not illustrate operant conditioning as clearly. Memorizing facts through repetition is a form of learning that does not necessarily involve reinforcement or punishment influencing behavior. Observational learning, as demonstrated by a person fixing their car after watching a mechanic, involves learning by watching others, which is distinct from operant conditioning. Lastly, studying to avoid losing a scholarship is motivated by the desire to prevent a negative outcome, which aligns more with avoidance learning than the reinforcement-based model central to operant conditioning.