Autokinesis and peripheral stimuli: implications for fixational stability.

The reduction in autokinesis of a fixated stimulus was determined as a function of the eccentricity of an identical second stimulus. When the stimuli were separated by 1 deg, autokinesis was reduced by approximately 50% but with increasing separation the attenuation was diminished. The results are interpreted in terms of fixational stability models of autokinesis. It is suggested that autokinesis as well as other examples of apparent movement result from fixational instability.