Michèle Robert

Have Sex Differences in Spatial Ability Evolved from Male Competition for Mating and Female Concern for Survival

Drawing on the theoretical and empirical foundations of two evolutionary models, we argue that, among humans and other mammals, a twofold selection process would parsimoniously account for sex-linked advantages in spatial contexts. In males, a superiority for both solving navigation-related spatial problems and understanding physical principles that apply to the behavior of projectiles could have been inherited from mating-oriented male competition involving extensive ranging and agonistic displays. In females, a form of superior spatial memory may have been shaped in relation to a costly reproduction system compelling them to safeguard their survival and that of their offspring by fostering low-risk strategies consisting of restricted navigation as well as concentration on nearby spatial cues. Based on the combined action of competition and survival pressures, we submit new predictions as to spatial sex differences in several species including humans.

Are there gender differences in verbal and visuospatial working-memory resources?

Whereas women generally outperform men in episodic-memory tasks, little is known as to how the genders compare with respect to basic working-memory operations. In reference to Baddeleys (1986) model, the present study searched for possible gender differences in terms of accuracy (but not speed) of working-memory processes. Men and women completed series of working-memory tasks respectively involving verbal and visuospatial information, as well as a double-span task involving both classes of information. Control measures included verbal fluency and mental rotation tasks in which gender differences are frequently obtained. In these tasks, the results showed several of the expected gender contrasts. However, men and women were not found to differ significantly in any type of working memory save in the double-span task where women surpassed men. The patterns of task intercorrelation were largely similar in both genders. Discussion emphasises the manifestation, based on the present exploration, of an almost identical working-memory architecture in men and women.

Perception and representation of the Euclidean coordinates in mature and elderly men and women

Research on gender differences in visuo-spatial tasks has been mostly limited to samples of preadolescents, adolescents, and young adults. In a life span perspective, the present study attempted to complete the available information by submitting mature and elderly men and women to three tasks involving the Euclidean spatial system. Aged 40 to 61, 62 to 72, and 73 to 84, and maximally equivalent across age and sex groups, the subjects performed the Rod-and-Frame Test, the water-level task, and a plumb-line task. Proficiency was expected to decrease with age and to be higher among men. It was found that, whatever their age, men surpassed women in the water-level and plumb-line tasks, whereas no gender difference was obtained on the Rod-and-Frame Test. Irrespective of sex, the oldest subjects were outperformed by the youngest on the Rod-and-Frame Test, while water-level and plumb-line achievement was independent of age. Depression and anxiety scores were not correlated with visuo-spatial performance. Discussion focused on the fact that the present highly homogeneous and selective sample allowed for the valid emergency of a distinctive pattern of gender and age contributions to the use of appropriate vertical and horizontal references once maturity is reached.

Does men's advantage in mental rotation persist when real three-dimensional objects are either felt or seen?

In several spatial tasks in which men outperform women in the processing of visual input, the sex difference has been eliminated in matching contexts limited to haptic input. The present experiment tested whether such contrasting results would be reproduced in a mental rotation task. A standard visual condition involved two-dimensional illustrations of three-dimensional stimuli; in a haptic condition, three-dimensional replicas of these stimuli were only felt; in an additional visual condition, these replicas were seen. The results indicated that, irrespective of condition, men’s response times were shorter than women’s, although accuracy did not significantly differ according to sex. For both men and women, response times were shorter and accuracy was higher in the standard condition than in the haptic one, the best performances being recorded when full replicas were shown. Self-reported solving strategies also varied as a function of sex and condition. The discussion emphasizes the robustness of men’s faster speed in mental rotation. With respect to both speed and accuracy, the demanding sequential processing called for in the haptic setting, relative to the standard condition, is underscored, as is the benefit resulting from easier access to depth cues in the visual context with real three-dimensional objects.

Spatial ability and home-range size: Examining the relationship in western men and women (Homo sapiens)

In mammals, spatial sex differences may have coevolved with sex differences in the size of home ranges. This study first evaluated whether, in keeping with most mammals and traditional human (Homo sapiens) societies, home ranges are larger in male than in female Westerners. Second, it established whether navigation patterns are associated with a broader set of spatial abilities in men than in women. Results showed that current male home ranges surpass female home ranges. Ranging was also positively correlated with achievement in tests of mental rotation, surface development, and location memory among men only, whereas it was associated with embedded figures scores in both sexes. Overall, these findings substantiate the adaptive role of several spatial sex differences in humans.

Water-Level Representation by Men and Women as a Function of Rod-And-Frame Test Proficiency and Visual and Postural Information

In the water-level task, it has been repeatedly shown that, compared with men, women more often fail to represent the surface of a liquid as horizontal regardless of the tilt of the container. An attempt was made to reduce this robust gender gap through the manipulation of relevant upright references conveyed both by the position of the stimuli and the posture of the subject. It was reasoned that bringing the women to focus on such gravitational references through postural adjustment might help their performance equal that of men, thus shedding some light on the nature of the difficulty they experience in the standard setting. A lesser effect was anticipated among men. However, the results showed that, even after controlling for proficiency in the correlated visuospatial situation of the rod-and-frame test, the performance of men always surpassed that of women. Irrespective of gender, water-level representation on vertical sheets was unaffected by the subjects posture, whereas it improved when horizontal sheets were coupled with the most unstable posture. Whereas the persistence of the yet-unaccounted-for gender difference was underscored, the contributions of visual and postural cues issued at arm and full-body levels were discussed.

The Gender Difference in Orienting Liquid Surfaces and Plumb-Lines: Its Robustness, Its Correlates, and the Associated Knowledge of Simple Physics

In comparison between male and female psychology students, a greater proportion of female students fail to represent liquid surfaces and plumb-line objects as invariably horizontal and vertical, respectively. However, the occurrence of this perplexing gender difference has not been ascertained among young adults enrolled in science programs, who should ostensibly be more fully equipped in terms of academic competence, irrespective of their gender. The present large sample of undergraduates (N = 1412), majoring in natural and applied sciences, and social sciences or humanities and arts, completed water-level and plumb-line items, along with other simple physics problems, indicating how and in reference to which principle they had solved these tasks. They also answered questions pertaining to possible personal proficiency correlates of a biological, experiential, perceptual, and sociocognitive nature. The data revealed not only that womens achievement was consistently poorer than mens across discipline categories, but surprisingly that this was so even within specific fields requiring and providing the most visuo-spatial skills as well as physical knowledge and training. Especially for women, mastery was predicted by success in simple physics problems, and to a lesser degree by perceptual, sociocognitive, and experiential variables. Biological variables did not contribute to proficiency for either gender, though the data fitted a recessive gene model. Responses based on relevant physics principles were more accurate, but men and women generally adopted the same procedural strategies. The present compelling demonstration of a gender gap in achievement that is not compensated by formal science education, extending thus even to future physical scientists, invites further investigation into its perceptual and cognitive determinants, as well as into those more distally connected with early aptitudes, interests, and experiences.

Women's deficiency in water-level representation: present in visual conditions yet absent in haptic contexts☆

The present experiment studied horizontality representation among men and women performing the water-level task either in visual conditions (the subjects saw outlines of tilted containers in which they respectively drew or set the water line) or in partially and totally haptic conditions (respectively, the subjects both saw and felt or merely felt the contours of the containers cut out of metal plates, and positioned a rod on the underside of the plates to indicate the water line). It was expected that, as the visual components of the setting were replaced by haptic ones, a reduction of the typical gender difference in proficiency would ensue. It was found that men surpassed women under visual conditions, whereas both genders were equivalent in haptic conditions. There were no gender or condition differences in a control task in which a line had to be placed horizontally in tilted containers. Forced reliance on proprioceptive cues among both men and women under the totally haptic condition was contrasted with the critical role played in visual conditions by visual references; those used by men were correct, whereas the ones used by women were incorrect.

The Female Advantage in Object Location Memory According to the Foraging Hypothesis: A Critical Analysis

According to the evolutionary hypothesis of Silverman and Eals (1992, Sex differences in spatial abilities: Evolutionary theory and data. In J. H. Barkow, L. Cosmides, & J. Tooby (Eds.), The adapted mind: Evolutionary psychology and the generation of culture (pp. 533–549). Oxford: Oxford University Press), women evolutionary hypothesis, women surpass men in object location memory as a result of a sexual division in foraging activities among early humans. After surveying the main anthropological information on ancestral sex-related foraging, we review the evidence on how robust women’s advantage in object location memory is. This leads us to suggest that the functional understanding of this type of memory would benefit from comparing men and women in carefully designed and ecologically meaningful cognitive contexts involving, for instance, incidental versus intentional settings that call for either the absolute or relative encoding of the locations of common versus uncommon objects.

Absence of a gender difference in a haptic version of the water-level task

The present experiment studied horizontality representation among men and women submitted to a haptic version of the water-level task. Without seeing the display, the subjects positioned a magnetic rod corresponding to the water line. It was found that the women performed as well as the men did, in contrast to the systematic male superiority under the standard visual version. Similarly, there was no gender effect when the subjects were instructed to set the rod horizontally in tilted containers. The absence of misleading visual information and the beneficial contribution of salient proprioceptive cues through haptic activity were suggested as possible determinants for the canceling of typical gender differences.