Victoria has had a phobia of public speaking for some time. They finally decided to see a therapist when they realized their new job would require them to run meetings, give presentations, and more. With a counselor, they began by creating a list of social situations from those that cause minor anxiety to those that make her want to run out of the room. They then began working on these situations and using techniques to help them remain calm and relaxed. This allows Victoria to gradually "unhook" the stimulus situation from their anxiety reaction. What is the core mechanism in this method?