Reasoning ability is (little more than) working-memory capacity?

This paper is concerned with the relationship between two central constructs—reasoning ability and working-memory capacity—which arise from two distinct bodies of literature on individual differences in cognition, the psychometric and the information-processing, respectively. In four separate studies ( N = 723, 412, 415, and 594), we assessed reasoning ability using various tests from the psychometric literature, and working-memory capacity using tests constructed according to Baddeley's (1986) definition of working memory. Confirmatory factor analysis yielded consistently high estimates of the correlation between working-memory capacity and reasoning ability factors ( r = .80 to .90). We also found differentiation between the two factors: Reasoning correlated comparatively highly with general knowledge; working-memory capacity correlated comparatively highly with processing speed. Inspection of residuals from model fitting suggested the existence of a verbal versus quantitative content factor. We discuss the implications of our results for what they tell us about the nature of reasoning, and the nature of working memory.