Name codes and features in the discrimination of letter forms.

Abstract

This research addressed the role of name and physical codes in visual discriminations and also tested the appropriateness of discrete stage models of information processing as opposed to continuous flow models. One group of subjects was required to discriminate the uppercase letters A and E from the set G and Q. Another group discriminated between the lowercase counterparts, set a and e and set g and q. RT was the dependent variable. A response competition paradigm was used in which the target letter was flanked by “noise” letters that were either response compatible or response incompatible. The noise letters could also be either in the same case as the target or in the alternate case. Thus, it was possible for the noise letters to be either physically identical to the target or identical in name only, and their features could be similar to the target in either one of the response sets. Although physical features of the stimuli played the major role in discrimination, name codes were found to facilitate performance when target and noise shared the same name. Feature similarity between noise letters and targets of the opposite response set produced interference, supporting a continuous flow conception of visual information processing.