An analysis of tactile letter confusions

Abstract

A confusion matrix of the whole block capital letters of the alphabet was obtained so as to examine the nature of tactile letter recognition, using a 17 by 17 matrix of tactile stimulators placed against blind subjects' backs. A hierarchical cluster analysis and a nonmetric multidimensional scaling technique were applied to the matrix. The results of the two analyses were consistent with each other and indicated that at least three independent basic letter features-enclosing shapes, vertical parallel lines, and angle of lines-play important parts in tactile letter recognition. Most confusion may be attributable to displacement of the apparent loci, omission or fusion of loci of stimulation, and failure to detect gaps in the tactile letters. © 1979 Psychonomic Society, Inc.