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.     

Simultaneity in Processing of Verbal and Spatial Information

Recent studies involving recall of verbal and spatial information produced conflicting results. In some cases investigators found males recalled verbal and spatial information equally well whereas females did less well on spatial than verbal information, but in other cases no sex differences were found. They also differed in that one study found processing of verbal and spatial information to be independent whereas others suggested trade-offs might occur. Using college-age subjects (17-25 yrs) with equal numbers of males and females (total n = 186) two experiments were performed to examine these differences. Although overall differences were found favoring verbal recall, females’ recall of spatial information was relatively poorer than males. Using a procedure designed to avoid possible artifactual depression of combined performance, we concluded that processing of spatial and verbal information is simultaneous in nature.

     

Perception of the horizontal and vertical in tangible displays: minimal gender differences

A study is reported of gender differences in a haptic version of three Piagetian tests that assess understanding of Euclidian space. A raised-line drawing kit was used both for subject responses and for production of stimuli. To test understanding of the horizontal, subjects felt pictures of a jar at four tilts and were asked to draw the water line. Two methods were used to examine understanding of the vertical. First, subjects drew a hanging electrical cord and light bulb, attached to the ceiling of a bus, parked on hills of four different angles. Subsequently, subjects drew telephone poles (represented by a single line) on hills of four different angles. In the jar task, males and females showed comparable performance, both groups showing large errors. Judgments of the vertical were very similar for males and females in the bus task, but errors diminished considerably for both genders when subjects drew telephone poles on hills. It is suggested that better judgments of the vertical in the pole task probably derive from the use of body-centered spatial reference information.     

Fear-related pictures deteriorate the performance of university students with high fear of snakes or spiders

Despite research regarding emotional processing, it is still unclear whether fear-evoking stimuli are processed when they are irrelevant and when attention is oriented elsewhere. In this study, 63 healthy university students with high fear from snakes or spiders participated in two different experiments. In an emotional modification of the spatial cueing task, 31 subjects (5 males) were asked to detect a target letter while ignoring a neutral or fear-related distracting picture. The distribution of attention was independently manipulated by a spatial cue that preceded the appearance of the picture and the target letter. In an emotional modification of the cognitive load paradigm, 32 subjects (4 males) were asked to discriminate between two target letters, while ignoring a central neutral or fear-related picture, and additional 1, 3, or 5 distracting letters that created a varied attentional load. Fear-related pictures interfered with the performance of highly fearful participants, even when the pictures were presented outside the focus of attention and when the task taxed attentional resources. We suggest that highly fearful individuals process fear-related information automatically, either inattentively or with prioritized attention capture over competing items, leading to deteriorated cognitive performance. Different results were shown in healthy individuals while processing negative--but not phobic--pictures, suggesting that emotional processing depends on the fear value of the stimulus for a specific observer.     

Unilateral nostril breathing influences lateralized cognitive performance

Relative nostril efficiency (nasal cycle) is related to hemispheric EEG differences and performance on cognitive tasks. We investigated how unilateral forced nostril breathing influences spatial and verbal performance. Right-handed males and females performed both tasks under either left-nostril, right-nostril, or free-breathing conditions. Unilateral breathing affects performance differently in males and females. It influences male performance ipsilaterally on both tasks: Their spatial performance is better during right-nostril breathing, and their verbal performance is better during left-nostril breathing. Unilateral breathing influences female performance contralaterally, but only on the spatial task: Their spatial performance is better during left-nostril breathing. These differences within and between sexes may exist because unilateral nostril breathing differentially activates the two hemispheres and thereby facilitates performance, or because attempts of the brain to control the nasal cycle unilaterally interfere with performance.     

Sex differences in spatial and non-spatial Y-maze performance after chronic stress

Chronic restraint is known to alter hippocampal CA3 dendritic morphology and spatial memory in male rats. The present study examined whether female rats, which exhibit different anatomical adaptations to chronic stress than those of males, would also show spatial memory impairments. Male and female Sprague-Dawley rats were restrained for 6 h/day for 21 days, a time frame previously demonstrated to cause hippocampal CA3 dendritic atrophy. The day after the last restraint session, rats were tested on a Y-maze, a habituation task that can be used to assess spatial memory. Chronic stress impaired Y-maze performance in both sexes without affecting levels of locomotion as measured by total arm entries in the first minute. However, Y-maze performance of stressed females improved in 2-5 min when chronically stressed males continued to show poor Y-maze performance. The enhanced Y-maze performance of chronically stressed females occurred when total arm entries were higher compared to the entries made by males. Therefore, correlations were performed between total arm entries and spatial memory in 1 and 2-5 min. In the first minute when control females demonstrated functional spatial memory, female controls with the lowest locomotor levels exhibited the best performance. The correlations for stressed females were not significant, and neither were the correlations for any group in 2-5 min. Overall, these results show important sex differences in response to chronic stress with females exhibiting an ability to recover quickly from deficits in Y-maze performance.     

Which spatial abilities and strategies predict males' and females' performance in the object perspective test?

The present study aimed to investigate whether different spatial abilities and strategies sustain perspective-taking (PT) performance in males and females. The PT task used was the Object Perspective Test (OPT, Kozhevnikov and Hegarty in Mem Cogn 29:745-756, 2001; Hegarty and Waller in Intelligence 32:175-191, 2004). A sample of 40 males and 40 females completed the OPT and several other visuo-spatial tasks and questionnaires. Multiple regression analysis showed that OPT performance was predicted positively by a spatial imagery preference and negatively by the specific use of mental rotation strategy (i.e. turning the sheet of paper). Gender interacted with the Embedded Figure Test (EFT), a spatial visualization task, since high EFT scores only positively predicted the OPT results in males. Overall, our results show that OPT performance is sustained by specific spatial abilities and strategies modulated, at least in part, by gender.     

The Relationships of Spatial Ability and Sex to Formal Reasoning Capabilities

The relationships of spatial ability and sex to performance on formal easoning tasks were examined for a group of 34 male and female college tudents. It was hypothesized that spatial ability is positively related to ormal reasoning task performance which is also related to male superiority on formal reasoning task performance. Results indicated that spatial ability vas unrelated to formal reasoning task performance and that sex differinces occurred with the balance task and the pendulum task which sugested that males were superior to females at manifesting the scheme of jroportionality and at being able to isolate variables.     

Sex differences in dynamic spatial ability: The unsolved question of performance factors

Males and females differ in several cognitive abilities, although the largest gap can be found in spatial ability. Some published studies make the claim that performance factors, which can be either subject- or task-related variables, explain these differences. However, previous studies in which performance factors were measured have focused on static spatial tests. Little is known about the role of performance factors in dynamic spatial tasks. In the present study, we analyzed a sample of 2624 university graduates to test the role of three performance factors (response latency, response frequency, and invested time) derived from the Spatial Orientation Dynamic Test-Revised (SODT-R; Santacreu, 1999). The results showed that males and females appear to cope with the dynamic task in different ways. However, males outperformed females even when the effects of the performance factors were partialed out; that is, the assessed performance factors did not explain much of the sex-related variance. Alternative ways of measuring performance factors will be needed if they are to explain sex differences in dynamic spatial ability.     

Sex differences in chronic stress effects on memory in rats

Recent studies in rodent models and in humans have shown that the status of both the gonadal and adrenal axes (hypothalamic-pituitary-gonadal, HPG and hypothalamic-pituitary-adrenal, HPA, respectively) can influence learning and memory function. In this article, the effects of activating the HPA axis (stress) on performance of memory tasks in rats are reviewed. More importantly, results are presented which show that chronic stress has a different impact on performance of these tasks depending upon the sex of the rat. These observations are novel and potentially important since few studies, animal or human, have utilized females as subjects in studies of the stress response. Sex differences in the effects of chronic stress on memory were investigated in rats using an object recognition task and two spatial memory tasks, radial arm maze and object location. Given the same chronic stress--21 days of restraint for 6 h each day--males were impaired in all of the memory tests while females showed enhanced performance of the spatial memory tasks and no changes in object recognition performance. Levels of neurotransmitters and metabolites were measured in brain areas important for cognition in the subjects in order to determine neural systems that may respond to stress and mediate the cognitive responses. These results show that responses of monoamine and amino acid containing neural systems may contribute to or underlie sex differences in stress effects on cognition. Stress decreased dopaminergic activity in the frontal cortex and amygdala of males but not females; whereas, in CA3 of the hippocampus, stress increased levels of 5-HT and norepinephrine in females, but not males, and increased GABA in males, but not females. Finally, a possible role for estradiol in mediating sexually differentiated responses to stress was examined. Behavioral and neurochemical evaluations in ovariectomized, stressed females, with or without estrogen replacement, suggest that sex differences in response to stress are influenced by both the organizing and activating effects of estradiol. A few, recent studies in humans, that show sexually dimorphic relationships between chronic stress and cognition, are also highlighted. These results in humans are consistent with the pattern of results in rats. Clearly, further studies are necessary to substantiate sex differences in stress effects on memory function in humans and to understand mechanisms whereby estrogen may influence the stress response in rats. Nonetheless, recent studies show sexually differentiated cognitive responses to chronic stress and underline the importance of considering the sex/gender of subjects when studying the stress response.     

The role of experience in spatial test performance: A meta-analysis

The hypothesis that spatial ability is, in part, experientially determined, and that sex differences in spatial ability can be explained by sex differences in spatial experience, can be studied in a correlational manner by examining the relationship between spatial activity participation and spatial ability test performance for males and females. Alternatively, an experimental training situation, comparing male and female susceptibility to training, has been proposed to test the hypothesis that environment has an impact on spatial skills and sex differences in ability. Both lines of research are reviewed here, through the use of meta-analytic techniques. The first meta-analysis reveals a weak but reliable relationship between spatial activity participation and spatial ability. This relationship appears similar for males and females. The second meta-analysis reveals that spatial ability test performance can be improved by training for both sexes. This improvement does not appear different for males and females, however, contrary to a predominant hypothesis in the literature. Training to asymptote may be a better test of the relevance of differential experience to sex differences. Content and duration of training are also discussed as important factors in the effectiveness of training.This research was supported by Grant No. MH39671 from the National Institute of Mental Health. A version of this paper was presented at the biennial meetings of the Society for Research in Child Development, Baltimore, Maryland, April 1987. We are grateful to Margaret Signorella and Susan Resnick for providing data. We would also like to thank Judith Dubas, Susan Resnick, Ralph Rosnow, Carolyn Spies, Lance Weinmann, and Marsha Weinraub for helpful comments on earlier drafts of this article.     

Improved mental rotation by near-sighted subjects

Several studies have shown significant correlations among factors such as sex, age, and hormone levels with performance on mental rotation tasks. To perform spatial rotation also seems to be related to cognitive abilities such as musical skills. The present experiment investigated a possible relationship for enhanced spatial abilities, as observed in near-sighted subjects, with mental rotation performance. 39 near-sighted and 21 normal-sighted subjects were tested on a mental rotation task using two-dimensional representations of three-dimensional objects. Near-sighted subjects displayed fewer errors in possible rotations than normal-sighted subjects. There was no difference in errors between groups in identification of mirror images ("impossible rotations"). Results were interpreted in terms of a relation between enhanced reliance on nonvisual information by near-sighted subjects and improved spatial representation.     

Sex differences in object location memory and spatial navigation in Long-Evans rats

In both humans and rodents, males typically excel on a number of tasks requiring spatial ability. However, human females exhibit advantages in memory for the spatial location of objects. This study investigated whether rats would exhibit similar sex differences on a task of object location memory (OLM) and on the watermaze (WM). We predicted that females should outperform males on the OLM task and that males should outperform females on the WM. To control for possible effects of housing environment, rats were housed in either complex environments or in standard shoebox housing. Eighty Long-Evans rats (40 males and 40 females) were housed in either complex (Complex rats) or standard shoebox housing (Control rats). Results indicated that males had superior performance on the WM, whereas females outperformed males on the OLM task, regardless of housing environment. As these sex differences cannot be easily attributed to differences in cognitive style related to linguistic processing of environmental features or to selection pressures related to the hunting gathering evolutionary prehistory of humans, these data suggest that sex differences in spatial ability may be related to traits selected for by polygynous mating strategies.     

Effect of sex and joystick experience on pursuit tracking in adults

Using a joystick, adults (n = 39 males, 40 females in Experiment 1; n = 35 males, 40 females in Experiment 2; and n = 18 males, 18 females in Experiment 3) performed a computerized pursuit tracking task. Contrary to previously reported findings, the males were not more accurate than the females when performance was adjusted for prior perceptual-motor experience. Although no sex differences were found in a speeded tracking task, in an inverted tracking task the males exhibited a significant performance advantage; that advantage remained after several blocks of practice. Because participants' performance was adjusted statistically for prior perceptual-motor experience, the male advantage in inverted tracking was not related to experience. Rather, more proficient inverted tracking performance was associated with higher 3-dimensional mental rotations scores. In sum, sex differences in normal pursuit tracking may be better explained by differences in perceptual-motor experience. Inverted tracking, however, may depend on proficiency with spatial transformations.     

Sex differences in cognition: the role of testosterone and sexual orientation

The performance of both heterosexual and homosexual males and females was compared on four cognitive tasks which have been shown to reveal evidence of sexual dimorphism. In one spatial and one verbal task, significant sex and orientation effects were found. Significant relationships were also found between salivary free-testosterone levels and performance on both spatial tasks, but no significant associations were found for performance on the two verbal tasks. The present study revealed both within- and between-sex differences in cognition and indicates that these differences may be partly accounted for by the activational effects of free testosterone.     

HEMISPHERE FUNCTION AND SPATIAL ABILITY: AN EXPLORATORY STUDY OF SEX AND CULTURAL DIFFERENCES

Three experiments investigated performance as a function of the visual hemifield to which verbal and spatial stimuli were presented tachistoscopically. The aim was to relate laterality effects to individual, sex and cultural differences in spatial ability within the framework of a model of hemispheric specialisation. A left-hemisphere advantage for verbal materials was obtained but no advantage for right-hemisphere presentation of visuospatial information occurred in the following samples: British and Ghanaian (experiment 1), high and low spatial ability groups (experiment 2) and males and females (experiment 3). Traditional spatial ability tests had no predictive value for performance on the tachistocopic tasks and an interaction between presentation field and responding hand was interpreted as implying equivalent processing of spatial information in either hemisphere.     

The influence of gender, handedness, and performance level on specialized cognitive functioning

Individual differences in performance on neuropsychological tests were analyzed across age (prepubertal to adult), gender, and handedness groups and examined for performance level as a moderating variable. No differences were observed for the factor structure of these tests across ages and between genders, suggesting similar cognitive structures among these groups. Significant differences in performance were observed between males and females and, to a lesser extent, between right and left handers. Of interest, were significant Gender x Handedness and Gender x Handedness x Level (of performance) interactions seen especially in the older (postpubertal and adult) subjects. High performing, right handed males and left handed females performed better on visuospatial tasks while left handed males and right handed females performed better on verbosequential tasks.     

Long-term continuous, but not daily, environmental enrichment reduces spatial memory decline in aged male mice

Although environmental enrichment improves spatial memory and alters synaptic plasticity in aged rodents, it is unclear whether all types of enrichment treatments yield similar benefits. The present study examined the effects in aged male mice of three types of enrichment on spatial memory in Morris water maze and radial arm maze tasks, and on levels of the presynaptic protein synaptophysin in several brain regions. Non-enriched young and aged males were compared with males exposed to one of the following treatments for 10 weeks: 5 min of daily handling, 3 h of daily basic enrichment, or 24 h of continuous complex enrichment. Young controls outperformed aged controls in both tasks. Neither daily handling nor daily enrichment affected spatial memory or synaptophysin levels. In contrast, continuous enrichment significantly reduced age-related spatial memory decline in both tasks, such that this group was statistically indistinguishable from young controls in most measures of performance. Continuously enriched mice were also significantly better than other aged mice in several spatial memory measures. Despite these improvements, synaptophysin levels in the continuous enrichment group were significantly lower than those of young and aged controls in the frontoparietal cortex, hippocampus, and striatum, suggesting a negative relationship between synaptophysin levels and spatial memory in aged males. These data demonstrate that different types of enrichment in aged male mice have disparate effects on spatial memory, and that the relationship between enrichment-induced changes in synaptophysin levels and spatial memory in aged males differs from that we have previously reported in aged female mice.     

Sex differences and the factor of time in solving Vandenberg and Kuse mental rotation problems

In accounting for the well-established sex differences on mental rotation tasks that involve cube stimuli of the Shepard and Metzler (Shepard & Metzler, 1971) kind, performance factors are frequently invoked. Three studies are presented that examine performance factors. In Study 1, analyses of the performance of a large number of subjects (n=1765) that performed the Vandenberg and Kuse (1976) mental rotation test (MRT) under standard conditions showed that the magnitude of the sex differences increases as subjects proceed through the sequence of problems, and that fewer females than males reach the last problems in a problem set. This supports the role of time constraints in sex differences on the MRT. Study 2 compared the magnitude of sex differences for subjects (n=212) who did the MRT under standard conditions (T1), and with double the time (T2) allowed for the test. No significant reduction in the magnitude of sex differences was observed-even though the overall scores under T2 increased markedly for both sexes. Study 3 examined the suggestion by that mental rotation differences arise because females spend more time than males in assuring that stimuli that do not match do indeed not match, with no sex differences for matching stimuli. This hypothesis was not supported for a sample of 20 males and 26 females. We conclude that performance factors may play a role in sex difference on mental rotation tasks, but do not account for all of the differences.     

Effect of Sex and Joystick Experience on Pursuit Tracking in Adults

Using a joystick, adults (n = 39 males, 40 females in Experiment 1; n = 35 males, 40 females in Experiment 2; and n = 18 males, 18 females in Experiment 3) performed a computerized pursuit tracking task. Contrary to previously reported findings, the males were not more accurate than the females when performance was adjusted for prior perceptual-motor experience. Although no sex differences were found in a speeded tracking task, in an inverted tracking task the males exhibited a significant performance advantage; that advantage remained after several blocks of practice. Because participants' performance was adjusted statistically for prior perceptual-motor experience, the male advantage in inverted tracking was not related to experience. Rather, more proficient inverted tracking performance was associated with higher 3-dimensional mental rotations scores. In sum, sex differences in normal pursuit tracking may be better explained by differences in perceptual-motor experience. Inverted tracking, however, may depend on proficiency with spatial transformations.