Low-spatial-frequency priming potentiates the high-level mechanisms of contextual influence

Abstract

The context sensitivity of visual size perception can be enhanced by prior exposure to low-spatial-frequency (LSF) relative to high-spatial-frequency information. Whether LSF priming affects low- or high-level mechanisms of contextual influence remains to be clarified. By using the Ebbinghaus illusion, which is a classic example of context-dependent size perception, we reduced the lightness contrast of surrounding inducers relative to the background and the shape similarity of the central target and surrounding inducers to diminish or eliminate low-level contour interaction and high-level size contrast, respectively. The results showed that LSF-related enhancement of context influence was unaffected by a change to the surround elements’ contrast but not by a change to the shape similarity between the target and surround. The findings provide evidence that LSF priming primarily affects high-level rather than low-level mechanisms of contextual influence, possibly by weakening the suppressive function of feedback connections from higher visual regions to the early visual cortex.