Psychological and physiological effects of subliminal stimulation

The work reported in this thesis investigates psychological and physiological effects of subliminal stimulation In clinical and non-clinical settings. The concept of subliminal stimulation, its use in clinical areas, and the syndrome of agoraphobia are discussed in the review chapters. Four experiments are then reported. The first three are concerned with the use of subliminal stimulation in the treatment of agoraphobia. The fourth experiment examines the responses of non-clinical subjects to a variety of subliminal films, in an attempt to replicate and extend the findings of Tyrer, Lewis and Lee (1978). The results of the experiments showed that: (1) subliminal, supraliminal and progressively faded films can all be used successfully in the treatment of agoraphobia; (2) the faded procedure gives the best clinical improvements; (3) the subliminal procedure is the least stressful for the patients; (4) physiological measures can be used to distinguish emotive or phobic supraliminal films from neutral supraliminal films; (5) physiological measures are neither a good indication of a patient's response to treatment, nor a reliable objective measure of the efficacy of the treatment; (6) when designing experiments to investigate subliminal effects, particular care should be taken to avoid fatigue effects, masking of subliminal stimuli by preceding supraliminal stimuli, and confounding of delayed responses in repeated measures designs. In the final chapter a number of possible directions for further research are described and discussed.