I was told that a reinforcer in classical conditioning can be an aversive stimulus which is hardly a reward at all. In instrumental conditioning, Skinnerians were also against equating a reinforcer and a reward. Skinner believed that a reinforcer strengthened any behavior that immediately came before the introduction of the reinforcer, while a reward is something that is given for a worthy accomplishment.....So, based on some of these distinctions, rewards may not necessarily reinforce desired behaviors. They also tend to lose their reinforcement value over time....Any thoughts on the difference between rewards and reinforcers?