P300 and information extraction in a display monitoring task
Carla M. Bosco · Illinois Digital Environment for Access to Learning and Scholarship (University of Illinois at Urbana-Champaign) · 1984
Previous research has found that the task relevance of a stimulus is an important factor in determining the amplitude of the P3Q0 component of the event »elated potential.This finding suggests that P300 amplitude can be used to measure the amount of information delivered by a stimulus.The reported study presented subjects with stimuli that differed in the amount of information conveyed in a display monitor' j task.P300 amplitude and reaction time (RT) were measured to assess the utility of the information to the subjects.Eleven subjects were presented with sequences of two types of stimuli, informative or imperative, and a warning.The informative stimuli were up or down arrows presented in octagons arranged in a triangle.The spatial postion of the octagons indicated the reliability (50%, 70%, or 90%) with which the informative cues predicted the state (up or down) of the imperative stimulus.The imperative stimuli were arrows presented in an octagon in the center of the triangle.Subjects responded to the direction of the imperative stimuli by pressing one of two buttons.Reaction time measures indicated that few of the subjects extracted the information delivered by the informative stimulus.The subjects that did appear to make use of the information had faster reaction times following the more reliable informative stimuli, yet these subjects did not exhibit P3GQ$ whose amplitudes were related to the Informative value of the stimuli.This may be due to the lack of stability of the system that was monitored.Future research will attempt to build a less complex system, and it is hoped that the P300 and reaction time measures will reflect the informative value of the stimuli..