Fraser N. Watts

Desensitization as an habituation phenomenon: I. Stimulus intensity as determinant of the effects of stimulus lengths

Abstract Desensitization is assumed to be an habituation phenomenon, and some foundations are laid for a multi-process theory based on the habituation of the orienting reflex. The importance of stimulus intensity as a moderating variable is emphasised. It is predicted and found that with items at the top of the hierarchy, desensitization is faster when long presentations are used, while for low items the reverse is the case. Also a distinction is made between long-term and short-term desensitization. The above predictions apply only to the former. When the latter is examined, it is found that for both high and low items, long presentations facilitate intersession anxiety reduction. The theoretical implications of the research are discussed, and questions needing further investigation are indicated.

Classical conditioning of a sexual deviation: A preliminary note

The problems often associated with aversion therapy led the authors to make use of a classical conditioning paradigm in the treatment of a young pedophiliac. The therapy, initially employing pictures of young girls as the UCS and of mature women as the CS, was successful in effecting normal heterosexual responsiveness outside the clinic as well as in the laboratory situation. Surprisingly, as treatment progressed, there was an accompanying diminution in deviant sexuality.

Desensitization as an Habituation Phenomenon: II. Studies of Interstimulus Interval Length

Predictions about the effect of interstimulus intervals (ISIs) in desensitization were made from the habituation model and tested with a series of Ss, each serving as his own control. Strong items desensitized faster with long ISIs, though weak items were not affected. No effects on long-term response decrements were found. A second experiment examined an interpretation of the stimulus-length effect in desensitization in terms of an extension of the recovery period between stimulus onsets. The results permitted rejection of the hypothesis.

Individual Differences in Response to Treatment

One aspect of behaviour therapy research that has been surprisingly slow to develop is the prediction of outcome from individual differences. In most other ways (the formulation of treatment methods precisely enough for them to be replicable, the controlled evaluation of treatment efficacy, the investigation of procedural variations which are of theoretical importance etc.) behaviour therapy research is relatively advanced. But curiously, the prediction outcome is much less well investigated than it is in some other treatment fields such as rehabilitation, which are in other ways at a lower level of scientific development than behaviour therapy.