A peripheral motion illusion and fixational eye movements

Ikuya Murakami1, Akiyoshi Kitaoka2, Hiroshi Ashida3,4

1Human and Information Science Laboratory, NTT Communication Science Laboratories, NTT Corporation, Atsugi, Japan, 2Department of Psychology, College of Letters, Ritsumeikan University, Kyoto, Japan, 3Graduate School of Letters, Kyoto University, Kyoto, Japan, 4Department of Psychology, Royal Holloway, University of London, Egham, UK

In peripheral viewing, a static pattern with asymmetrical luminance gradients appears to move in one direction. To examine the hypothesis that the source signal of the illusion originates in image motions due to small eye movements, we tested subjects with two experiments, one for rating of illusion saliency and the other for recording of small eye movements. The stimulus was rated as moving more clearly when free eye movements were allowed than when steady fixation was required. Under steady fixation, a positive correlation in the inter-subject scattergram was found: subjects with larger fixation instability saw more salient illusory motion. Under free eye movements, correlation was insignificant. It is suggested that small eye movements are related to this illusion.

2004 Elsevier Science Ireland Ltd. and the Japan Neuroscience Society. All rights reserved.

The 27th Annual Meeting of the Japan Neuroscience Society, Osaka, Japan, September 21-23, 2004