Answer:
John aversion conditioning. David systematic desensitization or exposure treatment
Step-by-step explanation:
Aversion conditioning refers of behavior therapy in which a stimulus that causes a feeling of dislike or disgust is corresponding with an unwanted behavior with the purpose of reducing or removing that behavior. This kind of therapy is based on learning theory which sustains that every behavior is learned and the behavior that are not ok can be unlearned if the circumstances allows it.
Systematic desensitization refers to the behavioral method in which a man is in a slackening exercise and gradually he is being exposed to the thing he is scared of. Usually this is useful to treat anxiety disorders and phobias.