Final answer:
Carl is using the teaching method known as shaping, a form of operant conditioning where reinforcements are given for successive movements toward a desired behavior.
Step-by-step explanation:
The teaching method Carl is using by reinforcing the dogs' behavior for each movement toward the hoop is known as shaping. Shaping is a method of operant conditioning where successive approximations toward a desired behavior are rewarded. Unlike classical conditioning, where an organism learns to associate two stimuli occurring together, operant conditioning involves learning a behavior through the consequences of that behavior. Shaping allows trainers to start with something the dog can already do, then gradually requires more specific actions before the reward is given, leading eventually to the full behavior - in this case, jumping through the hoop.