Inspection time and speed of processing: Sex differences on perceptual speed but not IT

Inspection time (IT) is a pattern backward masking task that correlates with IQ. Recently, IT has been shown mainly to measure general speed of processing (Gs). Females outperform males on tests of Gs, for example Digit Symbol (DS) from the Wechsler scales. Combining data from several studies we examined whether there were sex differences in IT. N = 653 adults and children completed a standard IT task and DS. Expected female superiority on DS was confirmed but there were no sex differences on IT. Nonetheless, DS and IT correlated with each other. These results confirm the psychological complexity of IT and support suggestions that IT may be useful as a biomarker to monitor cognitive changes that accompany ageing.