Orientation and tactile symbol recognition.

Abstract

This study was designed to evaluate the effect of orientation on the recognition of symbols drawn o n the skin. Recently, Heller (1980) reported that the retention of passively drawn numeral o r letter sequences requires slow presentation rates, since recall is degraded by the lingering effects of aftersensations. Recall of letter sequences was not influenced by orientation. Rock (1973) has described the effects of orientation o n form detection. It is not known, however, if orientation has an impact o n accuracy of recognition for individually drawn symbols. Thirty-six adult subjects were recruited from an undergraduate population. Each subject was exposed to blocks of 2 0 letters, limited to the letters A through 1, 2 0 consonants, and 20 digits (0-9) , in random order. The order of presentation of the blocks of symbols was completely counterbalanced. The symbols were drawn with a srylus on the preferred palm in an inverted orientation, an upright orientation, o r perpendicular to the arm axis, for independent groups of subjects. The method of presentation was similar to that employed by Heller ( 1 9 8 0 ) , as subjects were not provided with feedback or view of the skin. Subjects were required to identify each symbol verbally immediately after its presentation. The experiment was a mixed-factor analysis of variance, the factors being orientation and type of symbol, with repeated measures o n the last factor. The only significant effect was for type of symbol ( P = 29.85, p < .01).= W i t h the data collapsed over orientatinn, the mean frequencies correct for the leaers A through J, consonants, and digits were 82.5%, 77.2%, and 91.996, respectively. Orientation had no effect on recognition of symbols, but digits were easier to read than letters.