Related Experiment Video
Updated: Oct 2, 2026

Measuring Attention and Visual Processing Speed by Model-based Analysis of Temporal-order Judgments
Published on: January 23, 2017
Effects of voluntary attention on structured afterimages
1Department of Psychology, Grand Valley State Universty, Allendale, MI 49401, USA. loul@gvsu.edu
Abstract:
The effect of voluntary attention on afterimage fragmentation was explored in two experiments. The afterimage, in the form of a 30 degrees-tilted star of David, was generated after prolonged steady fixation in the first experiment, and with a brief and intense flash in the second experiment. Subjects were instructed to select various target shapes in the afterimage for attention and, at the same time, observe what was visible or invisible. Verbal reports and manual responses to afterimage changes were analyzed. Attended shapes were found to disappear from awareness Faster than unattended ones (experiment 1), and complementary shapes were found to predominate visual awareness when one of the pair was selected for attention (experiment 2). Voluntary attention was also found to affect closure (filling-in of enclosed regions) and smoothing of line figures in afterimages.
Related Concept Videos
Color Vision
Vision

