They then showed involuntary completion of the grid elements into a surface interacting with the static targets - creating an illusion of occlusion. When the grid appeared in front of the targets the proportion of disappearance was larger than when it was behind or on the same plane. Although to a lesser extent, MIB did nonetheless occur in the conditions where the perceptual occlusion was not taking place (targets were in front of the mask).
They then demonstrated that automatic completion of grid elements onto a surface interacting with stationary objects created an illusion of concealment, resulting in greater disappearance when the grid was in front of or overlapping the objects compared to behind or on the same plane. Although to a lesser extent, masking-induced blindness still occurred even when the objects were not occluded by the mask.