This study examined the factorial structure of the Wisconsin Card Sort
ing Test (WCST) in normal university students (N = 135) and a mixed cl
inical sample (N = 139). Two highly stable orthogonal factors were obs
erved accounting for 70 and 21 per cent of the variance, respectively.
Factor I was interpreted as reflecting undifferentiated executive fun
ction while Factor II may measure cognitive abilities associated with
attentional function. This work can serve as the basis for further exa
mination of the construct validity of the WCST and has implications fo
r its use.