Information processing analysis of the Chevreul pendulum illusion.

An information processing investigation was performed to quantify the Chevreul pendulum effect: the tendency of a small pendulum, when suspended from the hand and imaginatively concentrated on, to oscillate seemingly of its own accord. Using a time exposure photographic measurement technique, electronically automated visual and auditory imaginal prompts were presented to the subject during imaginal processing tasks. It was found that the pendulum effect was enhanced when vision of actual pendulum oscillations was permitted and visual or auditory spatially oscillating stimuli were present. Visual spatially oscillating stimuli were superior to their auditory counterparts. Results were discussed in terms of ideomotor and visual capture interpretations of signal and imaginal processing.