Sex differences in symbol-digit substitution and speeded matching

Sex differences in digit-symbol substitution and speeded matching tests have not been adequately explained. Recent attempts have suggested the importance of the comparison processes, associative memory, and a possible difference in processing verbal and spatial information. Four experiments, two on speeded matching and two on symbol-digit substitution, supported the hypothesis that both tests involve comparison processes and that the sex difference in these processes depends upon the type of information. A female advantage is clearest with verbal material on both matching and symbol-digit substitution tasks. A male advantage was found on a symbol-digit substitution test only after training on the symbol-digit associations and when symbol discrimination involved spatial orientation. These results question previous interpretations of the clerical speed and symbol-digit substitution tests in terms of perceptual encoding speed, attentional shifts or sex differences in motor skills.