Post-surgery perception of subjective contour figures in the cases of the congenitally blind

Abstract

The present experiment was planned to examine whether or not the congenitally blind after surgery were capable of seeing the subjective contour, when Kanizsa's original and a modified version of it were presented for the first time. Three subjects (M.O., To.M. and K.T.) who have continued a series of experiments for visual learning with us participated in the experimental runs. All subjects have already attained the ability to identify the 2D shape and solids. Initially it was expected that the subject's response could he classified as indicating that the subjective contours were seen or that they were not. However, it was round that (1) at least another two classes of responses should he added, and (2) that the commonly reported phenomenon of subjective contours in the normally sighted was rare in the congenitally blind subjects after surgery. A theoretical implication of the results is briefly discussed.