Daniel Voyer

Magnitude of sex differences in spatial abilities: a meta-analysis and consideration of critical variables.

In recent years, the magnitude, consistency, and stability across time of cognitive sex differences have been questioned. The present study examined these issues in the context of spatial abilities. A meta-analysis of 286 effect sizes from a variety of spatial ability measures was conducted. Effect sizes were partitioned by the specific test used and by a number of variables related to the experimental procedure in order to achieve homogeneity. Results showed that sex differences are significant in several tests but that some intertest differences exist. Partial support was found for the notion that the magnitude of sex differences has decreased in recent years. Finally, it was found that the age of emergence of sex differences depends on the test used. Results are discussed with regard to their implications for the study of sex differences in spatial abilities.

On the Magnitude of Laterality Effects and Sex Differences in Functional Lateralities

In the last 20 years, the hypothesis that men and women differ in functional lateralities has been used to account for sex-related differences in verbal and spatial skills. However, this hypothesis has not been clearly supported, with some reviewers confirming it (McGlone, 1980 for example), and others rejecting it (Fairweather, 1982 for example). The purpose of the present study was to provide a definite test of this hypothesis and to estimate the magnitude of overall laterality effects by means of a meta-analytic procedure. A total of 396 significance levels from a variety of studies on functional asymmetries utilising auditory, visual, or tactile presentation of verbal or nonverbal stimuli were sampled. Results showed that laterality effects tend to be large and significant but that they are heterogeneous in the visual modality. Homogeneity was generally achieved by a partition of the studies in terms of the specific task used. The results also showed sex differences to be significant in two modalities (visual and auditory). The data indicated the presence of sex differences in favour of men in functional asymmetries. However, it appears that the findings are not resistant to the file drawer problem. The results are discussed with regard to their implications for explanations of individual differences in cognitive abilities. The relation between functional lateralities and anatomical asymmetries is also discussed.

Gender differences in object location memory: A meta-analysis

The goal of the present study was to quantify the magnitude of gender differences in object location memory tasks. A total of 123 effect sizes (d ) drawn from 36 studies were included in a meta-analysis using a hierarchical approach. Object identity memory (37 effect sizes) and object location memory (86 effect sizes) tasks were analyzed separately. Object identity memory task showed significant gender differences that were homogeneous and in favor of women. For the object location memory tasks, effect sizes had to be partitioned by age (younger than 13, between 13 and 18, older than 18), object type (common, uncommon, gender neutral, geometric, masculine, feminine), scoring method (accuracy, time, distance), and type of measure (recall, recognition) to achieve homogeneity. Significant gender differences in favor of females were obtained in all clusters above the age of 13, with the exception of feminine, uncommon, and gender-neutral objects. Masculine objects and measures of distance produced significant effects in favor of males. Implications of these results for future work and for theoretical interpretations are discussed.

The Relation Between Experience and Spatial Performance in Men and Women

The purpose of the present study was to test the hypothesis that environmental factors affect the magnitude of gender differences in spatial performance only when the tasks used are susceptible to the influence of such factors. Two hundred and ninety White middle-class undergraduate students (165 females, 125 males) completed the Vandenberg and Kuse Mental Rotations Test (MRT), a paper and pencil version of the Water Level Task (WLT), and toys and sports preference questionnaires. Results revealed that males outperformed females on both spatial tests. In addition, a main effect of toys preference showed that participants with a spatial toys preference outperformed those with a nonspatial preference on both the MRT and the WLT. This main effect was qualified by an interaction between this factor and gender. The interaction was found only on the WLT and showed that gender differences were only significant in participants with a nonspatial preference. An interaction of sports preference and gender was also observed. This interaction revealed that, in contrast to what was obtained with toys, gender differences on both spatial tests were significant only in participants with a spatial sports preference. Implications of these findings with regard to the development of gender differences in spatial abilities are discussed.

Cognitive abilities in androgen‐insensitive subjects: comparison with control males and females from the same kindred

To determine the effect of androgen Insensitivity on cognitive abilities, subjects with the syndrome of complete androgen Insensitivity (Al) were compared to control males and females from the same kindred on the Spanish version of the Wechsler Adult Intelligence Scale (WAIS). All subjects had similar sociocultural backgrounds and only right‐handed subjects were used In the primary analysis. This design was chosen to diminish the effect of critical variables on test performance, thereby highlighting the effect of androgen unresponslveness on cognition.

Time limits and gender differences on paper-and-pencil tests of mental rotation: a meta-analysis.

The purpose of this study was to summarize research relevant to the influence of time limits on gender differences in paper-and-pencil tasks of mental rotation by means of a meta-analysis. Thirty-six effect sizes from published and unpublished studies examining the influence of time constraints were retrieved. Results showed that gender differences in mental rotation are significantly larger when the task is administered with time constraints compared to when such constraints are absent. In addition, the magnitude of gender differences was linearly related to the amount of time available for test completion. These findings were not related to the age or the year of birth of participants in the retrieved studies. The results are discussed with regard to their implications for explanations of gender differences in mental rotation and cognitive abilities in general.

Gender, level of spatial ability, and lateralization of mental rotation ☆

The present study indicates that some of the inconsistencies in studies of the lateralization of mental rotation may be a consequence of uncontrolled individual differences in the general level of spatial ability. In order to investigate the relation between spatial ability and the lateralization of mental rotation, 48 subjects (24 males and 24 females) were divided into three groups based on their performance on a standardized test of spatial ability. They then performed a lateralized two-dimensional mental rotation task. The results showed the typical mental rotation function in that angle of rotation and reaction time were linearly related. A significant spatial ability by visual field interaction indicated that subjects with low spatial ability had a left field advantage, whereas subjects with medium spatial ability showed no field advantage and subjects with high spatial ability showed a right field advantage. Gender also interacted with visual field, with males showing a left visual superiority and females an insignificant right visual field advantage. A significant three-way interaction of gender, spatial ability, and angle of rotation reflected the fact that low spatial males were more profoundly affected by rotation than the other groups. The results suggest that at least some of the inconsistent findings in studies of lateralization of mental rotation may be accounted for by differences in the level of spatial ability.

On the Reliability and Validity of Noninvasive Laterality Measures

The purpose of the present study was to quantify the reliability and validity of laterality effects obtained with noninvasive measures. A meta-analytic approach was used with 88 significance levels pertaining to reliability data and 11 significance levels concerning the validity of the measures. Results showed that reliability is affected by a number of procedural factors. In general, reliability was found to be at a moderate level. The validity of laterality measures was found to be significant but low. These findings suggest that more empirical work is needed to investigate and to improve the validity and reliability of the tasks used in the assessment of laterality effects.

Timing conditions and the magnitude of gender differences on the Mental Rotations Test.

In two experiments, we examined the effect of timing conditions on the magnitude of gender differences in performance on the Mental Rotations Test (MRT). In Experiment 1, each of 196 females and 119 males was administered the MRT via a Microsoft PowerPoint presentation in one of five timing conditions (15, 20, 25, 30, and 40 sec). The participants were exposed to each MRT item for the period specified in the assigned timing condition. Experiment 2 was conducted to address flaws found in Experiment 1. Accordingly, each of 105 females and 105 males was individually administered the task in one of three timing conditions (15 sec, 25 sec, or unlimited duration). The results of both experiments showed that the magnitude of gender differences was similar across timing conditions when a conventional scoring method was used. An analysis of guessing behavior generally indicated that men tend to show little effect of timing conditions, whereas women’s propensity to guess increases when they are given more time to respond. In general, the results supported an interpretation of gender differences on the MRT that relies on the joint operation of performance factors and level of spatial ability.

Scoring procedure, performance factors, and magnitude of sex differences in spatial performance.

The purpose of the present study was to demonstrate the influence of procedural factors on the magnitude of sex differences in a test of spatial ability. Two hundred and seven females and 155 males were administered the Mental Rotations Test (MRT) under timed and untimed conditions. Four different scoring procedures were used: total score, ratio of correct responses to the number of items attempted, score out of 24, and score out of 48. Significant sex differences were obtained in the timed condition but not in the untimed condition. Results also revealed that the magnitude of sex differences was reduced when a ratio score was used. Analysis of the pattern of responses provided insights into the causes of sex differences on the MRT. Results are interpreted in terms of their implications for research on sex differences in spatial ability.