Cortical Evoked Potentials and Vigilance: A Decision Theory Analysis

Abstract

Studies of the psychophysiological concomitants of vigilance performance are briefly reviewed. It is suggested that performance assessment has been inadequate or incomplete in the majority of these studies and that it would be profitable to utilize measures derived from statistical decision theory, particularly in relation to indices of cortical activity, in studies of vigilance. The evoked potential (EP) is then described and research relating late EP components to decision processes is outlined. The few experiments that have examined EPs in relation to vigilance performance are examined and suggestions for further research are made. These are implemented in two experiments on vigilance, the first concerned with the effects of event rate and signal regularity on measures of EP amplitude and of vigilance performance and the second with response latencies in vigilance and their associated EP component latencies. It is concluded that both late amplitude and latency measures of the EP are significantly related to (1) within-session performance changes, (2) differences in response latency associated with different response categories, and (3) the effects of independent variables such as event rate and signal regularity. In the last part of the paper a model is outlined in which both speed and accuracy measures of vigilance performance can be incorporated within a decision theory framework, and some preliminary results suggesting that EP late components provide correlates of decision processes in vigilance are discussed.