Afterimage of Perceptually Filled-in Surface: Demos

Shimojo, S., Kamitani, Y., & Nishida, S. (2001) Afterimage of perceptually filled-in surface. Science 293, 1677-1680.

Afterimage formed by adaptation to the color filling-in configuration

The image below induces perceptual color spreading or filling-in (red square), even though the stimuli are restricted to the four disk regions. When adapted to this image, one may observe an afterimage of the perceptually filled-in surface with an opponent color (global afterimage), as well as those of pacmen, wedges or disks (local afterimage).
  1. Gaze at the small dot between the pacmen at the bottom.
  2. Click the green button.
  3. Adapt to the image for 30 sec, then it disappears.
  4. Keep fixation, and observe afterimages for about 20 sec.

  5. (This demo may work better under low illumination)

Afterimage of dynamically induced filling-in

Static condition (left): Line segments are presented sparsely and statically. Their portions in a disk-shaped area are colored blue.
Dynamic condition (right): The same line segments undergo vertical apparent motion while the disk-shaped area is fixed. This display gives more vivid impression of color filling-in (disk-shaped surface) than the static condition. Note also that the duration of local adaptation is shorter than in the static condition.

Compare the global afterimage (disk-shaped surface) and the local afterimage (line segments) between these conditions. One may observe the global afterimage for a longer duration (more vividly), and the local afterimage for a shorter duration (less vividly) in the dynamic condition than in the static condition.

Perceptual surface segregation and its relevance to distinct afterimages

A. The adaptation stimulus.
B. Phenomenological segregation of surfaces in depth.
C. Afterimages which are corresponding to the surfaces and segregated in time.

Other illusion demos

Audiovisual "rabbit"
Filling-in by edge adaptaion
Sound-induced illusory flash (Shockwave Flash)
Sound-induced illusory flash (Quicktime)

Shimojo Lab
NTT Human Information Science Laboratory

Created by Yukiyasu Kamitani,
Last Modified: Jan 2, 2002.

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