How would behaviourist psychologists treat phobias?

There are two common forms of treatments that are based on the conditioning explanations of phobias. If phobias are acquired through classical conditioning and maintained through operant conditioning, systematic desensitisation aims to counter-condition the conditioned stimulus. A therapist will work with the patient to develop an anxiety hierarchy, which is a list of situations that involve the phobic stimulus that range from least to most scary. They will then teach the patient relaxation techniques such as meditation and mental imagery. Finally, the patient will work through the anxiety hierarchy and replace the fear with relaxation, until they reach the highest level of exposure. Alternatively, flooding aims for extinction. They do not try to replace fear, but rather remove it. Flooding consists of prolonged exposure to the phobic stimulus (often for several hours) until the fear response is eradicated - even if only through physical exhaustion.