Dogs that have a high reward drive are easier to train. I know it seems like I am adding another drive here, I always speak of four drives: The pack drive, the prey drive, the play drive and the sex drive, but a reward drive would probably fall under the pack drive. I am not even sure if a reward is a drive. It all depends on how the dog was conditioned or trained. Rewards do play a large roll in training a dog, whether it be a food reward or a toy reward. Obviously if the dog is trained to expect a toy reward, that is part of the play drive.