Similarity of auditory stimuli and generalization of skin conductance response habituation

Two alternative models for orienting response habituation to complex sequences of stimuli were formulated. Model 1 assumed complete generalization of habituation, while Model 2 assumed independent habituation processes for the different stimuli making up the complex sequence. Two experiments were conducted in order to compare the models. Experiment 1 was conducted to obtain a simple habituation function to tones. Experiment 2 utilized complex sequences, each comprising two tones. The degree of similarity between these two tones was manipulated by systematically varying the frequency of one of these tones, using a between-subjects design. The predictions of the two models were correlated with the SCRs of each subject. The results showed that the validities of the models depend on the similarity between the stimuli making up the complex sequence. For a sequence comprising very similar stimuli, Model 1 is a better description of the habituation process. Model 2, however, yields a closer fit to the habituation process to sequences comprising clearly discriminable stimuli.