Joseph Wolpe

Systematic Desensitization: A type of exposure therapy designed to reduce panic and anxiety responses, especially phobias; involves gradual exposure to feared object or situation along with relaxation exercises.

Exposure Therapy: A psychological treatment developed to help people confront their fears. The person is exposed to the feared object or context without any danger, in order to overcome their anxiety.

Reciprocal Inhibition: A concept in psychology which says that it's impossible for two opposing responses (like relaxation and fear) to occur at the same time, and that one can be used to eliminate the other.