TACTUAL PICTURE IDENTIFICATION BY BLIND AND SIGHTED PEOPLE - EFFECTS OF PROVIDING CATEGORICAL INFORMATION

Four experiments examined the influence of categorical information and visual experience on the identification of tangible pictures, produce d with a raised-line drawing kit. In Experiment 1, prior categorical i nformation aided the accuracy and speed of picture identification. In a second experiment, categorical information helped subjects when give n after the examination of each picture, but before any attempt at ide ntification. The benefits of categorical information were also obtaine d in another group of subjects, when the superordinate categories were named at the start of the experiment. In a third experiment, a multip le-choice picture recognition task was used to eliminate the difficult y of naming from the picture-identification task. The multiple-choice data showed higher accuracy and shorter latencies when compared with i dentification tasks. A fourth experiment evaluated picture identificat ion in blindfolded sighted, early, and late blind participants. Congen itally blind subjects showed lower performance than did the other grou ps, despite the availability of prior categorical information. The dat a were consistent with theories that assume that visual imagery aids t actual perception in naming raised line drawings. It was proposed that part of the difficulty in identification of raised line pictures may derive from problems in locating picture categories or names, and not merely in perception of the patterns.