The Influence of Uncertainty and Visual Complexity on Habituation of Electrodermal and Visual Orienting Reactions

ABSTRACT This experiment investigated the effects of stimulus complexity and stimulus uncertainty on habituation of the visual orienting reaction (VOR) and the skin conductance orienting reaction (SCR) in four groups of 14 subjects each. Half the subjects were told that the same stimulus would be presented a number of times in the right upper comer of the TV screen (“certain condition”), and the other half were not informed about the stimuli (“uncertain condition”). Within each of these groups, half the subjects received 14 stimuli of 12 bits information and the other half received 14 stimuli of 60 bits information. Stimulus complexity and stimulus uncertainty led to both slower habituation of the VOR and stronger VORs on trial 1. Neither factor, howev, had a significant effect on SCR magnitude or habituation. It was concluded that the VOR and SCR represent different aspects of stimulus processing. The results of this experiment were discussed in terms of the roles which VORs and SCRs may play in selective attention.