Abstract
The ‘association field’ (Field et al. 1993) model of contour integration predicts that contours comprised of sufficiently proximal edge elements become increasingly detectable with decreasing inter-element misalignment. We investigated a possible relationship between the association field and the perceptual fading of a contour under conditions of impending camouflage. We measured the effect of inter-element alignment on the duration of continued contour visibility using contours that were visible upon onset but faded into a camouflaging background within a few seconds. Even though the elements comprising the contours remained superimposed on the background, the contours always became fully camouflaged within a few seconds after contour onset. Our method allowed us to study the effects of inter-element orientation for considerably greater inter-element distances than those used in detection experiments. We used a continuous range of angular deviations from collinearity. This resulted in a parametric effect of inter-element alignment on the duration of perceptual fading such that contours comprised of maximally co-aligned elements remained visible (~500 ms) longer than those comprised of more randomly oriented elements. Consistent with findings from contour detection studies, contours remained visible longest (> 3 s) when co-aligned elements were parallel to the global contour (‘snakes’) as compared to perpendicular (‘ladders’). We conclude that the effect of inter-element alignment on delayed contour fading reflects the sustained operation of an association field mechanism. This mechanism binds discrete visual elements into global contours as a function of synchronous onset, inter-element distance and element co-alignment.
Meeting abstract presented at VSS 2013