B - 100 Principal Component Analysis of WAIS-IV Indices with the Serial Digit Learning Test.

These results replicated earlier research demonstrating that earlier SDL8 trials load on attentional/working memory measures and middle trials on processing speed. Unexpectedly, late trials loaded onto the Perceptual Reasoning Index, whereas they had previously loaded onto Verbal Comprehension of the WAIS-III. As these results may reflect the updated theoretical model underlying the WAIS-IV, further research replicating results which incorporated earlier WAIS-III perceptual reasoning (POI) measures is warranted.