hide
Free keywords:
-
Abstract:
The strength of the Poggendorff illusion has been determined by a nulling method for the classical as well as other configurations of the central
inducing region. Compared to a uniform field, an inducing rectangle with very low contrast produces a marked illusion, which saturates at a Michelson
contrast of about 0.1. With virtual borders of the Kanizsa type there is a weak illusion and this effect is attenuated when the 'pacman' sectors are occluded.
Texture borders without luminance contrast induce a stronger illusion. These results are discussed in relation to earlier data for contrast dependence of
Vernier acuity and for the orientation discrimination and tilt illusion with real and virtual borders.
