Utilization of redundant information by EMR and nonretarded adults.

When stimuli differed on two dimensions (size and shape), either of which furnished enough information for a correct response, retarded subjects were faster to discriminate than when stimuli differed on only one dimension. This result was also found with nonretarded subjects, and the data were taken to support the argument that both populations process information in this type of speeded visual discrimination in similar ways; whatever feature-testing model accommodates the data from nonretarded subjects also describes the data from retarded subjects.