The behavioural model concentrates only on behaviours and the responses a person makes to their environment, these can be external or internal. Behaviourists have tended to focus their attention on the role of external events and behaviours as these are more observable and therefore make gaining results easier. This means that not all aspects of abnormality are considered, a weakness of the approach as it is selective in its research. To gain a full understanding of behaviour all features would have to be monitored, it is easy for patients to show demand characteristics when being observed especially if only external behaviours are studied.
Research has not always supported the approaches claims. For example, conditioning theories of the acquisition of fear would struggle to explain why many people are unable to identify an incident in their past which led to traumatic conditioning. It also does not offer an explanation for why humans have certain fears ingrained about relatively harmless things and are perfectly comfortable with things that could potentially be harmful such as moving traffic.
Abnormal behaviour is no different from normal behaviour in terms of how it is learned. The approach suggests that abnormal behaviours are learned through conditioning or social learning as well behaviour is determined by external events. The principles of learning theory can be used to explain many disorders for which the major characteristics are behavioural. An example of this is arachnophobia which involves avoidance, an external symptom and feelings of anxiety when in the presence of a spider, an internal symptom.
In order to experiment features such as those considered by the behavioural approach it is likely that mostly laboratory studies and observations would be used to control extraneous variables that could affect the patient’s reactions. Because of this, ecological validity is reduced meaning that the results cannot be generalised to other situations outside of a controlled environment. Animal studies are also used as a means for collecting information on behaviours but these results cannot be generalised to humans entirely as there are obvious differences between them.
Learning environments may reinforce problematic behaviours for example avoidant behaviour lowers anxiety, depressive behaviours may elicit help and attention from others. Society also provides deviant maladaptive models that children identify with and imitate in order for social approval. The model ignores the role of biology or internal thoughts and feelings as an explanation for abnormality. Behaviourist explanations of abnormality have been criticised for offering a very limited view of factors that may cause abnormal behaviour.
Despite this, the theories have been successful in treating phobias and eliminating unwanted behaviour. The behavioural therapies only remove the symptoms and not the cause of a disorder and so can result in the symptoms being left to resurface. It is likely that the patient could relapse and return to the maladaptive behaviour. This differs from the psychodynamic approach that offers explanations for the causes of abnormality and allows them to be corrected making it a stronger theory that could have more appeal to psychologists.