Human Information Processing: Discrete or Continuous?

Increasing the intensity of visual and auditory targets increased response force in a simple reaction time (RT) task. For both, task-relevant and irrelevant auditory stimuli this effect was also obtained in go-no-go and choice RT tasks. The effect was not modulated by the task. These results bear on the discrete stage model (Sternberg, 1969) as long as it is assumed that intensity solely influences early stages while response force is determined in late stages. Results are consistent with a dual route model in which the effect of intensity is mediated via an arousal route bypassing normal information processing channels and connecting early stages with late stages (e.g. Sanders, 1983). However, results are also consistent with continuous models (e.g. McClelland, 1979). Further tests of the dual route model using response force are proposed