Stimulus intensity and information processing

Abstract

The physiological and behavioral literature regarding effects of stimulus intensity on the time course of information processing is reviewed. The physiological data describe intensity effects on the sensory pathway. Reaction time studies show that the effect of intensity on behavioral responses also depends on and may be mediated by more cognitive processes. The degree to which intensity affects simple reaction time varies directly with the response criterion subjects use. The lack of this dependence in choice reaction time may indicate different intensity effects on energy and nonenergy pathways. The literature suggests that intensity affects the time course of information processing not only by influencing the speed of processing in sensory pathways, but also by affecting alertness and the time required to direct attention to a stimulus.Stimulus intensity has been used extensively as an independent variable in psychological research, but· its use has been most closely associated with the field of psychophysics. As part of their general interest in the relation between stimulus magnitude and subjective magnitude, psychophysicists have relentlessly searched for the true law relating stimulus intensity to perceived intensity. There has been no doubt that the relationship is nonlinear. Rather, the questions have involved the type of nonlinearity that best describes the psychophysical data (logarithmic vs. power functions), the level in the processing system at which the nonlinear transformation occurs, and the dependence of the input-output relationship on such things as stimulus modality, duration, and size.The thoroughness of the psychophysicists' investigations of the effect of stimulus intensity on perceived intensity has not been paralleled by investigations of intensity effects on other psychological processes. It has been known since 1886 that reaction time decreases with stimulus intensity (Cattell, 1886). Recent studies in cognitive psychology have concentrated not on understanding how intensity affects reaction time but instead on using manipulation of intensity as a tool with which to investigate other cognitive factors. In Sternberg's (1969) influential stage model of information processing, stimulus intensity is explicitly assumed to affect only the earliest stages of encoding. Without questioning this assumption, psychologists have used intensity manipulations within the framework of the additive factors logic (Sternberg, 1969), arguing that any variable which interacts withThe author wishes to thank Michael 1. Posner and Richard T. Marrocco for helpful comments on this paper. Requests for reprints should be sent to Mary Jo Nissen, Eye Research Laboratories, The University of Chicago, 950 East 59th Street, Chicago, Illinois 60637. 338 stimulus intensity must also affect encoding. Considering the number of theoretical arguments that have been based on the assumption that intensity only affects the earliest stage of processing, it is important to know, specifically, whether that assumption is valid, an...

Response force is sensitive to the temporal uncertainty of response stimuli

“…These results contrast with those of Experiment 1, in which foreperiod length strongly affected RT. These different patterns are consistent with the claim that auditory stimulation produces automatic alerting/ arousal (Nissen, 1977;Sanders, 1975Sanders, , 1983, eliminating foreperiod effects on RT. Interestingly, however, an almost identical pattern ofresults was obtained for response force.…”

Effects of auditory stimulus intensity on response force in simple, go/no-go, and choice RT tasks

“…Warning signals, for example, affect reflex amplitudes and EEG (see, e.g., Brunia, 1993) as wel1 as RT and RF (see, e.g., Ulrich & Mattes, 1996), and some of these effects are known to depend on the intensity of the warning signal (see, e.g., Keuss, 1972). Warning signal effects are typically interpreted as evidence that warning stimuli produce nonspecific alerting or arousing effects that influence information-processing stages (see, e.g., Nissen, 1977)-precisely the same interpretation offered here for the effect of stimulus intensity on RF. Besides the effects of warning signals, similar arousal-based interpretations have been offered for the effects of sleep loss and noise (see, e.g., Broadbent, 1971), the threat ofelectrical shock (see, e.g., Jaskowski, Wroblewski, & HojanJezierska, 1994), knowledge of results (see, e.g., Steyvers, 1987), amphetamines and barbiturates (see, e.g., Trumbo & Gaillard, 1975), speed stress (Jaskowski, Verleger, & Wascher, 1994), and preparatory muscle tension (see, e.g., Brebner & Welford, 1980).…”

“…As discussed by Nissen (1977), postperceptual effects of stimulus intensity are important because they contradict models in which intensity influences only early perceptual processes. In these models, intensity cannot have 107…”

“…As discussed by Nissen (1977), postperceptual effects of stimulus intensity are important because they contradict models in which intensity influences only early perceptual processes. In these models, intensity cannot have even an indirect effect on downstream decision and motor stages, at least in tasks in which perceptual outputs are categorized independently of stimulus intensity (i.e., intensity is task irrelevant).…”

“…They found that the difference was less variable, from trial to trial, for loud stimuli than for soft ones. Like Angel's (1973) findings, this suggests that stimulus intensity directly influences response processes.As discussed by Nissen (1977), postperceptual effects of stimulus intensity are important because they contradict models in which intensity influences only early perceptual processes. In these models, intensity cannot have 107…”