Habituation of The Orienting Response to Complex Sequences of Stimuli

The present paper investigates habituation of the electrodermal component of the orienting response to complex sequences of stimuli—i.e. sequences of at least two different recurring stimuli. From the simple habituation curve to one stimulus, three alternative models are suggested to predict the response to that same stimulus in a given trial of the complex sequence. The study was carried out in two stages. In Experiment 1 simple habituation curves were constructed for two types of stimuli (chosen and non‐chosen). The results of this experiment provided two negative exponential functions fitted to the data of 101 subjects. Experiments 2 and 3 were designed to compare the models and used complex sequences of chosen and non‐chosen stimuli in different mixtures. The prediction of each model was correlated with the actual data of 120 subjects in Experiment 2 and 160 subjects in Experiment 3. The two experiments produced a similar picture regarding the relative validities of the three models. The two models that assume independent habituation processes of the two stimuli comprising the sequence fitted the data better than a model that assumes complete generalization of habituation. The results were discussed within the framework of Sokolov's theory. Theoretical and methodological implications of the models were mentioned, and several suggestions for further research and formulation of more complex models were proposed.