Selective Filling-in of Large Artificial Scotoma

Abstract

The experiments were conducted on 17 inch monitor at 54 cm observation distance. At the upper and lower 7 degree eccentric positions, the 2 green (x =0.38, y =0.62, L =141cd) filled circles of 7 degree diameter were presented for the targets which would eventually disappear on the red (0.64, 0.34, 41) background. At the concentric positions the unfilled white (0.33, 0.38, 220) circles with 0.2 degree thickness which shrank smoothly from 11 degree diameter to 9 degree in one second and jumped back (0.42cd) to the 11 degree. The change repeated indefinitely. The target was white. The background was composed of gray (0.32, 0.36, 26) and black areas. The left and right half areas were black and gray respectively, or the inside of the center circle of 7 degree radius and outside of it were black and gray respectively. The background was black. The targets were yellow (0.40, 0.50, 192). The white vertical meridian line and the unfilled circle of 7 degree radius of 0.4 degree thickness which passed under the centers of the targets were presented. The many vertical lines background was presented. The dynamic random dots which were the optimal stimuli for fillingin were examined. The target size and the transient nature of the disappearance were the principal differences from the conventional MIB. The failure of the line segments filling-in would be due to the large size of the targets, though the positive filling-in of the equivalent size real blind spots still remains as a mystery. The negative texture filling could lead a conjecture that they would really need a few seconds observation.