The relationship between speed of information processing as measured by timed paper-and-pencil tests and psychometric intelligence

Abstract

The relationship between speed of information processing and IQ was examined using timed paper-and-pencil substitution tests to measure processing speed. The measures of IQ were two paper-and-pencil cognitive aptitude tests. Sixty-two college men and women were subjects. The correlations of processing speed with IQ were low but generally statistically significant; high speeds went with lower IQs when the response was simply copying alphanumerics and with higher IQs when the response required coding (i.e., mental transformations). When handwriting speed was removed from the coding scores to obtain a purer measure of processing speed, the correlations with IQ rose. The psychometrically better IQ test showed a strong linear relationship between mean time to code and its correlation with IQ; the relationship was somewhat weaker with the psychometrically poorer IQ test. The results replicate the essential findings of Jensen and others who find negative correlations between reaction time (RT) and IQ. The results are interpreted in terms of a working hypothesis that simple coding and RT tasks share with IQ tests a common mental decision or Spearman g factor which leads to their intercorrelation. The results suggest that substitution tests measure IQ because they measure speed of information processing.