Pupillary Changes during a Decision-Making Task

Abstract

The effects on pupil size of a simple decision-making task were examined. Ss were assigned to either an experimental group ( n = 7) or a yoked control group ( n = 7). Ss in the experimental group were given a 2-choice decision task and on each trial S was presented 2 alternative directions in which a lever could be moved. S had to decide the direction to move the lever and, subsequently, make the response. Ss in the control group received essentially the same task conditions except no decision was required, since S was told which direction to move the lever. Results showed significantly greater pupillary dilation during the decision period in the experimental group than in the control group and these findings were discussed in terms of cognitive load.