A psychophysiological investigation of cognitive-energetic relations in human information processing: a heart rate/additive factors approach

This study focused on Sanders' (1983) cognitive—energetic model of information processing. The first experiment examined effects of three computational variables and two state variables on reaction time (RT), anticipatory heart rate (HR), and concurrent changes in ordinal interbeat intervals (IBIs) using a complete factorial Additive Factors Method (AFM) design (Sternberg 1969). The computational variables were Stimulus quality, Number of response alternatives, and Foreperiod duration and the state variables included an emotional (Shock-treat versus Control) and a motivational Task-involvement (best versus worst RT) variable. In the second experiment the three computational variables were randomized on a trial-by-trial basis. The three computational variables had additive effects on RT in Control and best RT conditions and interactive effects in Shock-threat and worst RT conditions. Under suboptimal conditions created by the state variables, the results showed a consistent interaction between Stimulus quality and Number of response alternatives. Heart rate was decreased for the long foreperiods and under Shock-threat. IBIs near the stimulus varied with Foreperiod. According to AFM logic, the RT results suggested a serial stage structure of information processing. The current results provide evidence for selective rather than general effects of suboptimal conditions on choice RT which is consistent with the essential assumptions of Sanders' model. The data are interpreted most easily by assuming that Shock-threat causes malfunctions of arousal, and possibly activation, and that Task-involvement affects effort. The heart rate data provided complimentary information, in particular with the processes operating during the foreperiod. The results were discussed using a variety of Sanders' model which incorporates existing notions of foreperiod effects.