The scintillating grid illusion in stereo-depth

The dark scintillating dots occurring on a gray-on-black, modified Hermann grid [Schrauf, M., Lingelbach, B., & Wist, E. R. (1997). The scintillating grid illusion. Vision Research, 37, 1033-1038] were studied in stereo-depth by assigning various degrees of disparity to the white inducing disks. Dependent on the sign of disparity, the disks and the dark illusory spots within them appeared to lie either in the same plane, in front of, or behind the grid. At zero disparity, illusory strength was maximum and was the same for stereo, binocular and monocular viewing. With increasing disparity, the illusion became progressively weaker; however, the decrease for stereo-patterns was significantly less than for control patterns presented binocularly or monocularly. These results suggest a central contribution to the scintillation effect.