Sex differences in mental rotation strategy

When humans decide whether two visual stimuli are identical or mirror images of each other and one of the stimuli is rotated with respect to the other, the time discrimination takes usually increases as a rectilinear function of the orientation disparity. On the average, males perform this mental rotation at a faster angular speed than females. This experiment required the rotation of both mirror-image-different and non-mirror-different stimuli. The polygonal stimuli were presented in either spatially unfiltered, high-pass or low-pass filtered versions. All stimulus conditions produced mental rotation-type effects but with graded curvilinear trends. Women rotated faster than men under all conditions, an infrequent outcome in mental rotation studies. Overall, women yielded more convexly curvilinear response functions than men. For both sexes the curvilinearity was more pronounced under the non-mirror-different, low-pass stimulus condition than under the mirror different, high-pass stimulus condition. The results are considered as supporting the occurrence of two different mental rotation strategies and as suggesting that the women were predisposed to use efficiently an analytic feature rotation strategy, while the men were predisposed to employ efficiently a holistic pattern rotation strategy. It is argued that the overall design of this experiment promoted the application of an analytic strategy and thus conferred an advantage to the female participants.     

Sex differences and the role of figural complexity in determining the rate of mental rotation

Two experiments were conducted to investigate the effects of figural complexity on the rate of mental rotation of 3-dimensional figures and to compare the performance of men and women. Complexity was manipulated in three ways: by changing the number of blocks in the figure (7 or 10), by altering the number of turns (2 or 3), and by using outline or solid figures. In the first study, these factors were manipulated between groups of subjects. Women showed steeper slopes than men, but none of the complexity variables affected either slope or intercept for the mental rotation function. In the second study, number of turns and number of blocks were manipulated within-subjects, using only the solid figures. There were significant sex differences in both slope and intercept, and the number of blocks affected the slope of the rotation function. In both studies, a small percentage of the subjects showed nonlinear functions relating angular rotation to response time. Although the women consistently showed slower rotation functions, rate of rotation did not relate either to figural complexity or to nonlinearity. The results suggest that the rate of mental rotation is not affected by figural complexity, at least at the levels used in the present study, and that men and women employ essentially similar strategies.     

Sex differences in parietal lobe morphology: relationship to mental rotation performance

Structural magnetic resonance imaging (MRI) studies of the human brain have reported evidence for sexual dimorphism. In addition to sex differences in overall cerebral volume, differences in the proportion of gray matter (GM) to white matter (WM) volume have been observed, particularly in the parietal lobe. To our knowledge there have been no studies examining the relationship between the sex differences in parietal lobe structure and function. The parietal lobe is thought to be involved in spatial ability, and particularly involved in mental rotation. The purpose of this study is to examine whether sex differences in parietal lobe structure are present, and if present to relate these differences to performance on the mental rotations test (MRT). We found that women had proportionately greater gray matter volume in the parietal lobe compared to men, and this morphologic difference was disadvantageous for women in terms of performance on the MRT. In contrast, we found that men compared to women had proportionately greater parietal lobe surface area, and this morphologic difference was associated with a performance advantage for men on mental rotation. These findings support the possibility that the sexual dimorphism in the structure of the parietal lobe is a neurobiological substrate for the sex difference in performance on the mental rotations test.     

Developmental differences in mental rotation.

A reaction time paradigm was used to investigate developmental differences in ability to rotate and compare imaginal representations. Third grade, fifth grade, and college students (ages 9, 11, and 20 years, respectively) were required to determine whether a letter of the alphabet was presented in its backward or normal position. Letters were presented at 0, 60, 120, 180, 240, or 300° orientations from upright. Subjects were given no advance information about a test letter, or they were given identity and orientation information. In the no information condition, reaction time increased for all age groups as a function of the departure in orientation of the test letter from an upright position. In the advance information condition, reaction time remained uniform across orientation for only the college subjects. The developmental implications of these findings are discussed.     

Sex differences in time perception

In an experiment on discrimination of duration of auditory stimuli in the range of milliseconds 16 men and 16 women were tested. Men scored better than women in discrimination of duration as well as in required session time. These results were discussed in terms of the assumption of a neurotransmitter-related internal clock and with respect to sex differences in reaction time.     

Hemisphere differences for components of mental rotation

The hemispheric functional lateralization of components of mental rotation performance was investigated. Twenty right-handed males were presented with rotated alphanumerics and unfamiliar characters in the left or right visual field. Subjects decided if the laterally presented stimulus was identical to or a mirror image of a center standard stimulus. Reaction time and errors were measured. Previous mental rotation findings were replicated and the visual field variable produced significant effects for both dependent measures. An overall right visual field advantage was observed in the latency data, suggesting a left hemisphere superiority for at least one component process of the task. A significant interaction in the error data showed that alphanumerics produced less errors in the right visual field than in the left visual field, consistent with a left hemisphere superiority for processing verbal symbolic material. No such hemispheric difference in accuracy was found for unfamiliar characters.     

Sex differences in the time course of emotion

Conventional wisdom holds that women are more "emotional" than men. However, research evidence suggests that sex differences in emotion are considerably more complex. The authors tested hypotheses about sex differences in the engagement of the approach and avoidance motivational systems thought to underpin emotional responses. The authors measured reported emotional experience and startle response magnitude both during the presentation and after the offset of emotional stimuli that engage these motivational systems to assess whether men and women differ in their patterns of immediate response to emotional stimuli and in their patterns of recovery from these responses. Our findings indicated that women were more experientially reactive to negative, but not positive, emotional pictures compared to men, and that women scored higher than men on measure of aversive motivational system sensitivity. Although both men and women exhibited potentiation of the startle response during the presentation of negative pictures relative to neutral pictures, only women continued to show this relative potentiation during the recovery period, indicating that women were continuing to engage the aversive motivational system after the offset of negative emotional pictures.     

Sex differences in children's time use

A sample of children (410 on a school day and 347 on a non-school day) was examined to determine differences in time spent in household work, leisure activities, school, paid work, personal care, and sleep by males and females. Males spent more time in leisure activities and less time in household work and personal care than females. Differences in time allocation appeared to be in accordance with traditional male-female roles. These patterns were established at early ages.     

Sex differences in problems related to depression

The study investigated possible sex differences in the types of problems that are correlated with Beck Depression Inventory (BDI) scores, using a sample of college students. Problems related to assertiveness and feeling ill at ease were positively correlated with BDI scores for males, but not for females. In contrast, conflicts with parents, feelings of being boxed in and of boredom, lack of money, and chronic physical complaints were positively related to BDI scores for females, but not for males.     

Visual field differences for clockwise and counterclockwise mental rotation

Geometric line drawings were presented to normal subjects in the left visual field (LVF) or right visual field (RVF) at various degrees of rotation from a centrally presented vertical standard. The task of the subject was to indicate with a reaction time (RT) response whether the laterally presented stimulus could be rotated into the vertical standard or if it was a rotated mirror image of the standard. In Study 1, an overall right hemisphere superiority was found for RT and accuracy on match trials. Most interestingly, interactions between Visual Field and Rotation Angle for the match accuracy data and between Visual Field and Direction of Rotation (clockwise or counterclockwise) for the match RT slopes were found. These interactions suggested that clockwise rotations were more readily performed in the LVF and counterclockwise rotations in the RVF, consistent with other literature for mental rotation. The purpose of Study 2 was to replicate this finding of visual field differences for rotation direction using a design in which direction and degree of rotation were varied orthogonally. No main effect of Visual Field was found. However, significant interactions between Visual Field and Rotation Angle were found for both RT and accuracy, confirming the presence of visual field differences for rotation direction in a new sample of subjects. These differences were discussed in terms of the possibly greater relevance of medially directed stimuli and a possible hemispheric bias for rotation direction, and in terms of interhemispheric transmission factors.     

Understanding spatial transformations: similarities and differences between mental rotation and mental folding

Mental rotation and mental folding, two widely used measures of spatial ability, both require the dynamic spatial transformation of objects with respect to their internal spatial structure. Traditionally, however, these two skills have been considered quite distinct, based primarily on factor analyses of psychometric data. This paper reviews the similarities and differences between mental rotation and mental folding from a variety of perspectives, including their definitions, component cognitive processes, neurological bases, developmental trajectories, malleability, predictive validity, and psychometric properties. We conclude that mental rotation and mental folding are similar in many respects. However, the tasks differ in whether they require rigid or non-rigid transformations of objects. In addition, mental rotation shows robust sex-related differences whereas mental folding does not. We also identify specific questions for which research is lacking.     

Covariation of sex differences in mental rotation with body size

Sex difference in mental rotation ability was reconsidered. The Vandenberg-Kuse figures were administered to 120 male and 76 female students from the Medical School of BlackSea Technical University in Trabzon, Turkey to assess the mental rotation ability. Students' height and weight were measured. As expected, men outperformed women on this test and had greater height and weight. Number correct on mental rotation test significantly correlated with height and weight for the total sample and for men, but only with weight for women. Using weight as covariate, the sex difference was no longer significant. The mean mental rotation score was significantly higher for heavy women than for light men. There was a positive correlation between weight and mental rotation test scores for heavy women, but height and weight were negatively correlated with mental rotation test scores for light men. These results suggest that there is no sex difference in mental rotation ability as measured.     

Item type,occlusion, and gender differences in mental rotation

Two experiments were conducted to examine the role of item type in mental rotation. In each experiment, participants completed two computerized mental rotation tasks, one with blocks as stimuli and one with human figures as stimuli. The tasks were formatted either as a multiple-choice psychometric test (Experiment 1) or as a same–different type task (Experiment 2). Aside from the expected replication of a decreased effect of occlusion on women's accuracy when processing human figures compared to block figures, it was hypothesized that response times would increase when processing the complex but familiar human figures, compared to the simple but unfamiliar block figures. In Experiment 1, the results relevant to occlusion were replicated. However, the presence of a speed–accuracy trade-off suggested that participants processed human figures faster but less accurately than block figures. In Experiment 2, both men and women performed faster and more accurately when processing occluded human figures than when processing nonoccluded human figures. The effect of item type, its potential link to embodied cognition, and the role of strategy selection on gender differences in mental rotation are discussed.     

Two- vs. three-dimensional presentation of mental rotation tasks: Sex differences and effects of training on performance and brain activation

The well-documented sex difference in mental rotation favoring males has been shown to emerge only for 2-dimensional presentations of 3-dimensional objects, but not with actual 3-dimensional objects or with virtual reality presentations of 3-dimensional objects. Training studies using computer games with mental rotation-related content have demonstrated training effects on mental rotation performance. Here, we studied the combined effect of a two-week mental rotation (MR) training on 2-dimensional vs. 3-dimensional presentations of a classic Shepard–Metzler task (presented in a pretest–training–posttest design) and their accompanying cortical activation patterns assessed via EEG in a sample of 38 male and 39 female adolescents of about 15 years of age. Analysis of one performance parameter (reaction times) displayed only main effects of dimensionality (with shorter RTs on the 3D vs. 2D version of the MR task) and of training (significant shortening of RTs), but no significant sex difference. Analysis of the other performance parameter (scores) in the MR task revealed a sex difference favoring males that first, appeared only in the 2D version, but not in the 3D version of the MR task and, secondly, diminished after training. Neurophysiologically we observed a complex sex × dimensionality × training × hemisphere interaction showing that the hypothesized decrease of brain activation (increase in neural efficiency) with training emerged for males in both 2D and 3D conditions, whereas for females this decrease was found only in the 3D but not with the 2D version of the MR task.