These and many other theorists helped to develop the general orientation now called psychodynamic therapy, which includes the various therapies based on Freud's essential principle of making the unconscious conscious. In the 1920s, behaviorism became the dominant paradigm, and remained so until the 1950s. Behaviorism used techniques based on theories of operant conditioning, classical conditioning and social learning theory. Major contributors included Joseph Wolpe, Hans Eysenck, and B.F. Skinner. Because behaviorism denied or ignored internal mental activity, this period represents a general slowing of advancement within the field of psychotherapy. Wilhelm Reich began to develop body psychotherapy in the 1930s. Starting in the 1950s, two main orientations evolved independently in response to behaviorism—cognitivism and existential-humanistic therapy. The humanistic movement largely developed from both the Existential theories of writers like Rollo May and Viktor Frankl (a less well known figure Eugene Heimler) and the Person-centered psychotherapy of Carl Rogers. These orientations all focused less on the unconscious and more on promoting positive, holistic change through the development of a supportive, genuine, and empathic therapeutic relationship. Rollo May, Carl Rogers, and Irvin Yalom acknowledge the influence of Otto Rank (1884-1939), Freud's acolyte, then critic. During the 1950s, Albert Ellis developed the first form of cognitive behavioral therapy, Rational Emotive Behavior Therapy (REBT) and few years later Aaron T. Beck developed cognitive therapy. Both of these included therapy aimed at changing a person's beliefs, by contrast with the insight-based approach of psychodynamic therapies or the newer relational approach of humanistic therapies. Cognitive and behavioral approaches were combined during the 1970s, resulting in Cognitive behavioral therapy (CBT). Being oriented towards symptom-relief, collaborative empiricism and modifying core beliefs, this approach has gained widespread acceptance as a primary treatment for numerous disorders. Since the 1970s, other major perspectives have been developed and adopted within the field. Perhaps the two biggest have been Systems Therapy—which focuses on family and group dynamics—and Transpersonal psychology, which focuses on the spiritual facet of human experience. Other important orientations developed in the last three decades include Feminist therapy, Somatic Psychology, Expressive therapy, and applied Positive psychology. Clinical psychology in Japan developed towards a more integrative socially-orientated counseling methodology. Practice in India developed from both traditional metaphysical and ayurvedic systems and Western methodologies. Since 1993, the American Psychological Association Division 12 Task Force has created and revised a list of empirically supported psychological treatments for specific disorders.