Type of items and the magnitude of gender differences on the Mental Rotations Test

The present study considered the structure of the drawings used in the Mental Rotations Test (MRT) to examine whether distractors that are either a mirror image or structurally different from the target as well as response alternatives with occluded and nonoccluded parts affect the magnitude of gender differences on this test. One hundred and three women and 100 men undergraduate students were given unlimited time to complete the MRT. A gender by occlusion interaction on correct responses showed that gender differences were larger for occluded than for nonoccluded items. Examination of performance as a function of item placement in the test suggested that it is unlikely that the results could be accounted for by differential practice effects in women and men. Implications of these results for explanations of gender differences on the MRT and for the training of spatial abilities are discussed.