Individual differences in visual discrimination of letters.

Research on the distinctive features of letters has been inconclusive. Investigators may have overlooked individual variations in their data which would have supported feature-extraction hypotheses but were concealed by analyses which averaged data into group means. Response latencies from a matching discrimination task with the 26 English capital letters were analyzed with INDSCAL, a multidimensional scaling procedure which weights individual contributions to a psychological space. Underlying a dimensions were linearity, curvature, angularity, and closure. The solution disclosed that individuals utilized these features differentially in the visual discriminations. The results suggest that future research in visual feature extraction will benefit from the examination of individual variations in the perceptual process.