Sex differences in visuo-spatial ability: task difficulty, speed-accuracy tradeoff, and other performance factors.

Abstract Males have consistently been found to perform better than females on a task that requires the subject to mentally rotate a figure. Recently, Goldstein, Haldane, and Mitchell (1990) suggested that performance factors are operative in explaining sex differences in spatial ability. However, Stumpf (1993) was unable to replicate all of Goldstein et al.'s (1990) findings and to generalize them to other measures of spatial ability. In this study, it was hypothesized (1) that females would take longer to respond and would get fewer correct items than males on a spatial rotation task, and (2) that only females would show a speed-accuracy tradeoff as the difficulty of the spatial task increased from the 90Degree to 180Degree rotated conditions. The results confirmed each of these hypotheses. Furthermore, as Stumpf (1993) found, when ratio scores from the number of items correct to number attempted were computed for both males and females, differences in spatial ability were reduced, though still evident. Sex differences in visual-spatial ability have remained one of the most persistent findings in cognitive ability studies. A considerable amount of evidence suggests that males tend to be superior to females in tasks that are spatial in nature, including maze performance, block design, mental rotation, picture assembly, and mechanical skills (Halpern, 1992). These sex-related differences have been extensively reported, and despite the overwhelming amount of evidence towards male visuo-spatial superiority, the controversy still continues (cf. Halpern, 1992) In particular, male performance has been consistently found to be higher than female performance on a task that requires the subject to mentally rotate a three-dimensional array of cubes (Sanders, Soares, & D'Aquila, 1982). As Halpern (1989) states, this sex difference in mental rotation ability represents one of the largest cognitive sex differences to date. Numerous theories have been proposed to explain the nature and origin of sex differences in spatial skills (e.g., biological approaches stressing the genetic, maturational, or hormonal factors as possible etiologies, environmental approaches that stress the role of different socialization experiences; cf. Halpern, 1992). Recently, Goldstein, Haldane, and Mitchell (1990) stated that the effects of experiential or task factors (i.e., performance factors) on the spatial task behavior of the two sexes have been virtually ignored. For example, Maccoby and Jacklin (1974) found that males tended to perform tasks quickly, whereas females tended to work more slowly and carefully. Such task variables as time limits or task difficulty, as well as experiential factors such as previous task exposure and self-efficacy, may contribute to the differences evident across males and females in spatial ability. To examine the effects of these performance factors, Goldstein et al. (1990) administered the Mental Rotations Test (MRT; Vandenberg & Kuse, 1978) to two different samples of college students who had very high SAT quantitative scores. The study showed a significant effect in favour of males for spatial ability when the task was scored in the conventional way (i.e., number of correct responses). However, when the test was administered without a time limit or scored with a ratio score of the number of items solved to items attempted, score differences between the sexes were no longer significant. The results clearly suggest that the females in the sample attempted fewer items on the MRT than males, and, when corrected for these errors of omission by using a ratio score, the gap between males and females was considerably less. Therefore, it appears that performance factors do contribute to apparent sex differences in spatial ability. Mills, Ablard, and Stumpf (1993), however, administered the School and College Ability Test (SCAT), and were unable to replicate this reduction in effect size that Goldstein et al. …