Changes in pupil size during an imagery task without motor response involvement

Abstract

A previous study showed that pupillary dilation is associated with attempts to generate mental images to stimulus words, image arousal being indicated by a key press. The present study revealed similar but attenuated dilation effects when the key press response was eliminated, The difference can be interpreted in terms of motivational effects of task difficulty, or arousal effects associated directly with the motor response. © 1966, Psychonomic Press. All rights reserved.