A group of theorists, researchers and mental health professionals reacted against the previous models that were then prominent in the field of psychology, in particular, the psychodynamic and biological models. The behaviorists agreed with the psychodynamic model insofar as the assertion that while there were likely biological contributions to mental difficulties, physiological factors could not explain 100 percent of mental health and disease. These theorists were not comfortable with the belief that every aspect of physical, mental and emotional health was biological in nature despite the actual physical causes to many areas of health being unknown. Behaviorists accepted that many things were biological in nature, including certain aspects of mental functioning. Yet at the same time they asserted that not everything was determined by biology opposed the practice of blindly believing this to be the case despite the fact that most physiological determinants and associated factors related to health were unknown.

Behaviorists took issue with the psychodynamic model, however, regarding their general methodology and approach to assessment and treatment. Those who advocated for the behavioral model asserted that the psychodynamic model was characterized by loose treatment guidelines and a lack of empiricism. These deficiencies, it was argued, were demonstrated by the failure to keep detailed records documenting specific treatment techniques that lead to decreased symptoms and improved adjustment. These behaviorists believed that the processes that the psychodynamic model emphasized, in particular the heavy emphasis on the unconscious, could not be observed and relied exclusively on patient report and therapist interpretation. Behaviorists argued that both of these methods were inherently biased. Furthermore, there was no way of proving or disproving whether the therapist was accurately interpreting what they obtained from the patient since it was all based on the patient’s unconscious. Behaviorists also made the case that it was possible that patient’s reported feeling better and being less distressed due to demand characteristics or wanting to please the therapist.

So the Behavioral Model agreed that the manifestations of mental functioning might have certain physiological contributions, and that there were likely contributions to mental functioning that were not fully conscious. However, at the same time they rejected the Biological and Psychodynamic models due to the fact that the targets of treatment and treatment outcomes could not be observed and measured. Additionally, behaviorists believed that neither model posited any useful explanation of how psychological difficulties developed in individual patients.

Behaviorists stated that the only valid and useful framework for addressing psychological functioning was learning theory. They dismissed the two models that predated the Behavioral Model for lack of empirical rigor and the inability to objectively evaluate target problems and to reveal the actual mechanisms that determined treatment success in a demonstrable manner. The inability of biological proponents to demonstrated actual, not theoretical, causal factors, and a perceivable process or a standardize approach were addressed by behaviorists through a focus on only what was observable; behavior.

The Behavioral Model concluded that if the target problem could be observed and measured they could not come up with a well- grounded method of changing or eliminating it. Furthermore, the model held that the efficacy of treatment could be detailed at each step and measurement would allow the therapist to determine if the treatment was having the desired effect. If it wasn’t effectively addressing the problem, the treatment could be altered or replaced as was deemed appropriate based on the empirical account of progress or lack thereof. Objectively observable and measurable phenomena, these theorists contended, was the only reliable means of establishing that the desired change had occurred. Relying solely on what the patient reported lacked scientific vigor, the behaviorists stressed, since it was commonly known that patient report was notoriously undependable. The behaviorists stressed the belief that only that which could be observed, quantified and measured was an acceptable target of assessment and intervention. They banished private mental events, memories, meaning, thoughts and any other internal unseen process from inclusion in the behavioral theory (Benjamin, 2007).