Final answer:
Systematic desensitization is based on classical conditioning and involves gradually exposing the individual to their fear alongside relaxation techniques to replace the fear response with a relaxation response.
Step-by-step explanation:
Systematic desensitization, used to treat phobias, is based on the learning principle known as classical conditioning. This therapeutic technique involves the gradual exposure to the feared object or situation, accompanied by relaxation practices such as diaphragmatic breathing or biofeedback. The goal is to replace the fear response with a relaxation response through repeated associations in a controlled environment. This approach aligns with the understanding that phobias are learned through classical conditioning and that new learning can help overcome the irrational fears associated with these phobias.