Effects of Physical Size and Complexity on Tactual Discrimination of Blind Children

Abstract

The effects of physical size and complexity of metric figures on tactual discrimination performance was investigated with 36 blind children in grades 1 and 2. Metric figures from three levels of complexity (3 × 3, 4 × 4, and 5 × 5) were combined factorially with three physical sizes (1, 2, and 4 inches) in a same-different pair-comparison discrimination task. Increasing levels of physical size and complexity had no effect on discrimination accuracy, but increasing levels of either physical size or complexity significantly increased task time. Overall accuracy of performance was low (62 percent correct discriminations), and it appeared that unsystematic and inappropriate hand and finger motions were responsible for the low level of performance.