Identifying Simple Numerical Stimuli: Processing Inefficiencies Exhibited by Arithmetic Learning Disabled Children

Abstract

Children with arithmetic learning disabilities (ALD) and normally achieving (NA) controls were administered a battery of computerised tasks, including numerical and letter matching, naming latency, and memory span. The letter spans as well as the digit spans of the ALD children were smaller than those of their NA peers, arguing against the hypothesis of a specific deficit in working memory for numerical information. Although the ALD children were no slower than their NA peers in accessing either numerical or letter codes, their pattern of correlations between numerical and letter judgements both within and between the matching and naming-latency tasks differed from that of the NA group, suggesting a difference in the means by which these children access numerical representations. Another particularly intriguing result was that the ALD children failed to use the most efficient procedure when judging name identity for physically same numerical stimuli. Additional evidence indicated that this may have been due to dysfunctional subitizing. These and other findings confirm that ALD children display several processing inefficiencies when judging simple numerical stimuli.