Send to

Choose Destination
Vision Res. 2006 Jul;46(15):2421-31. Epub 2006 Mar 20.

A positive correlation between fixation instability and the strength of illusory motion in a static display.

Author information

Human and Information Science Laboratory, NTT Communication Science Laboratories, NTT Corporation, Japan.


A stationary pattern with asymmetrical luminance gradients can appear to move. We hypothesized that the source signal of this illusion originates in retinal image motions due to fixational eye movements. We investigated the inter-subject correlation between fixation instability and illusion strength. First, we demonstrated that the strength of the illusion can be quantified by the nulling technique. Second, we concurrently measured cancellation velocity and fixation instability for each subject, and found a positive correlation between them. The same relationship was also found within a single observer when the visual stimulus was artificially moved in the simulation of fixation instability. Third, we confirmed the same correlation with eye movements for a wider variety of illusory displays. These results suggest that fixational eye movements indeed play a relevant role in generating this motion illusion.

[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center