Grouping effects in flash-induced perceptual fading.

We show that the flash-induced fading effect can be influenced by grouping based on colour and shape similarity. In flash-induced fading, peripherally presented elements perceptually disappear after a flash has been presented around or next to the element(s) (Kanai and Kamitani, 2003 Journal of Cognitive Neuroscience 15 664-672). In the present study, two elements (which could either be similar or different in both colour and shape) were presented at an eccentricity of 2.6 degrees from a fixation cross. After 2 s, a short flash (40 ms) was presented around one of the elements. The two elements remained on the screen for 2.5 s after the flash. We found a higher percentage of mutual perceptual disappearance when the two elements were similar in colour or in shape. These results converge with other findings showing that perceptual fading phenomena are influenced by effects of perceptual grouping. This indicates that, besides low-level adaptation, more global processes play a part in perceptual fading as well and should thus be taken into account in giving a full explanation of perceptual fading in general.