Mental health articles

OF mental health care and mentally ill

Formation of behaviour disorders

Behavioural therapies are based on the assumption that mental disorders are maladaptive behaviours which have resulted from faulty learning. The case of Little Albert, given in Chapter 1, provides an example of the way that phobias may be learnt. The solution is therefore to unlearn the behaviours. Learning occurs through either association (classical conditioning) or through reinforcement (operant conditioning), and the therapies based on these are known as behaviour therapy and behaviour modification respectively.

In both cases the focus is on the individual’s present symptoms, not the historical causes of the problem. Before we can explore the different types of therapy that have utilised these principles, it is essential to outline what is involved in the two types of conditioning. Note that in both cases what is being produced is learning, which can be defined as ‘a relatively permanent change in behaviour that occurs as a result of experience’. This definition excludes behaviours that are the result of physical changes, either temporary states such as those induced by drugs, or permanent states such as those resulting from accidents (e.g. amputations). Classical conditioning procedures have been derived from Pavlov’s studies of salivation in dogs in 1927. These showed that if a bell was rung just before food was presented, dogs would learn to salivate to the bell alone after a series of such trials. The reflex response of salivation had become associated with a new stimulus, i.e. the bell. The procedure shows the terms that Pavlov introduced for the different components of the conditioning process. Learning in this situation depends on two principles: contiguous association (presenting the stimuli to be associated—the bell and the food, for example-close together in time); and the law of exercise (repetition of this pairing). The process also has other important characteristics. Extinction is the first of these, whereby omission of the unconditioned stimulus (e.g. food) leads eventually to the conditioned response no longer being shown. The second, generalisation, refers to the tendency to show a conditioned response to stimuli similar to the original conditioned stimulus (e.g. similar sounding bells). The last, discrimination, is the ability to learn not to generalise, but to respond only to one specific conditioned stimulus.

For the present purposes it is also important to note that although the phenomenon was originally demonstrated in dogs, this type of learning has also been shown to occur in humans. From the point of view of mental disorder, the most important reflex response is that of fear, since if this can be associated with new stimuli there are important implications for both the origins of disorders and for treatment. Operant conditioning was originally termed ‘instrumental conditioning’ by the American psychologist Thorndike in 1913, and later renamed by its most famous theorist, Skinner (1938). The latter demonstrated that in a piece of apparatus called a Skinner box, (shown in Figure 4.2) a rat or pigeon would learn to press a lever or peck at a light in order to get a reward of food. It would learn to avoid behaviours that were followed by unpleasant consequences such as electric shocks. Therefore the consequences of these voluntary behaviours is what determines whether or not they will be repeated; this became known as the law of effect. To increase the frequency of a behaviour (i.e. to reinforce it) there are two possibilities. The behaviour can be followed by positive consequences such as food (positive reinforcement), or by the omission of a negative event such as electric shock (negative reinforcement). It is also possible to decrease the frequency of behaviour by means of giving something unpleasant (punishment) or removing something pleasant (frustrative non-reward).

As with classical conditioning, extinction can occur if reinforcement is omitted, and generalisation and discrimination have also been demonstrated. In the case of operant conditioning, generalisation and discrimination can extend or narrow the range of responses that are given as well as extending or narrowing the range of stimuli that are responded to. For example, instead of jumping on a lever as a response, a rat may reach up and pull it down with its paw. Another important aspect of this type of conditioning is the possibility of behaviour shaping, whereby completely new behaviours can be developed gradually by rewarding any which are more similar to what is wanted. The animal will have to display something closer to the desired behaviour each time before it is rewarded, a process known as successive approximation.

These processes have been specifically applied to the acquisition of mental disorder by Mowrer (1947) in his two-factor model of fear and avoidance. He suggested that fear of specific stimuli may be acquired through classical conditioning (first factor), so that a reflexive fear response becomes linked to new stimuli (such as spiders). This fear is unpleasant, so the individual learns to reduce it by avoiding the conditioned stimuli, which is an example of operant conditioning (second factor) through negative reinforcement. Such responses are extremely resistant to extinction.

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