Stimulus hierarchy generalization in systematic desensitization

A group of snake phobic Ss were desensitized to the first 5 items of a standard 7 item snake fear hierarchy in which the items were ordered on the basis of distance from a snake. This group and a no-treatment control group (which did not receive the desensitization) were treated for fear of all the hierarchy stimuli in terms of ratings both before and after the desensitization. The Ss rated their fear responses to all the stimuli as presented to them in (1) real form (2) by slide, and (3) in imaginal form. The results verified all four experimental hypotheses: (1) The experimental Ss showed greater fear reduction than the control Ss to both the training stimuli (the stimuli on which desensitization done) and the generalization stimuli (the other two stimuli), (2) The systematic desensitization (SD) group showed (a) more fear reduction to the last training stimuli than to the lower generalization stimulus and (b) more to the latter than to the higher generalization stimulus, (3) The SD group showed less fear reduction to the generalization stimuli in their real form than in both the slide and imaginai modalities (in the desensitization each stimulus presentation was done first in slide form and then in imaginal form), and (4) There were significant overall individual differences in generalization of fear reduction to the generalization stimuli.