A Sex Difference in Mental Rotation in Infants: Convergent Evidence

A meta-analysis of mental rotation in the first years of life

Mental rotation, the cognitive process of moving an object in mind to predict how it looks in a new orientation, is coupled to intelligence, learning, and educational achievement. On average, adolescent and adult males solve mental rotation tasks slightly better (i.e., faster and/or more accurate) than females. When such behavioral differences emerge during development, however, remains poorly understood. Here we analyzed effect sizes derived from 62 experiments conducted in 1705 infants aged 3-16 months. We found that male infants recognized rotated objects slightly more reliably than female infants. This difference survives correction for small degrees of publication bias. These findings indicate that gender differences in mental rotation are small and not robustly detectable in the first months of postnatal life. RESEARCH HIGHLIGHTS: We analyzed effect sizes of 62 mental rotation experiments including 1705 infants. Looking time reveals that 3-16-months-old infants are able to perform mental rotation. Mental rotation is slightly more reliable in male infants compared to female infants. Gender difference in mental rotation is robust to small degrees of publication bias.

A Novel Approach to Assessing Infant and Child Mental Rotation

Mental rotation is a critically important, early developing spatial skill that is related to other spatial cognitive abilities. Understanding the early development of this skill, however, requires a developmentally appropriate assessment that can be used with infants, toddlers, and young children. We present here a new eye-tracking task that uses a staircase procedure to assess mental rotation in 12-, 24-, and 36-month-old children (N = 41). To ensure that all children understood the task, the session began with training and practice, in which the children learned to fixate which of two houses a giraffe, facing either left or right, would approach. The adaptive two-up, one-down staircase procedure assessed the children's ability to fixate the correct house when the giraffe was rotated in 30° (up) or 15° (down) increments. The procedure was successful, with most children showing evidence of mental rotation. In addition, the children were less likely to succeed as the angle of rotation increased, and the older children succeeded at higher angles of rotation than the younger children, replicating previous findings with other procedures. The present study contributes a new paradigm that can assess the development of mental rotation in young children and holds promise for yielding insights into individual differences in mental rotation.

An investigation of mental rotation in infancy using change detection

Two experiments were conducted to examine mental rotation in 6- to 12-month-old infants (N = 166) using a change detection task. These experiments were replications of Lauer and Lourenco (Lauer et al., 2015; Lauer & Lourenco, 2016), using identical stimuli and variations of their procedure, including an exact replication conducted in a laboratory setting (Experiment 1), and an online assessment using Lookit (Scott et al.,2017; Scott & Schulz, 2017) (Experiment 2). Both experiments failed to replicate the results of the original study; in neither experiment did infants' behavior provide evidence that they mentally rotated the object. Results are discussed in terms of the robustness of mental rotation in infancy and about limits in our experimental procedures for uncovering perceptual and cognitive abilities in infants.

Sex differences matter: Males and females are equal but not the same

Sex differences between males and females can be detected early in life. They are present also later even to a much greater extent affecting our life in adulthood and a wide spectrum of physical, psychological, cognitive, and behavioral characteristics. Moreover, sex differences matter also in individual's health and disease. In this article, we reviewed at first the sex differences in brain organization and function with respect to the underlying biological mechanisms. Since the individual functional differences in the brain, in turn, shape the behavior, sex-specific psychological/behavioral differences that can be observed in infants but also adults are consequently addressed. Finally, we briefly mention sex-dependent variations in susceptibility to selected disorders as well as their pathophysiology, diagnosis, and response to therapy. The understanding of biologically determined variability between males and females can have important implications, especially in gender-specific health care. We have the impression that it is very important to emphasize that sex matters. Males and females are differently programmed by nature, and it must be respected. Even though we as males and females are not the same, we would like to emphasize that we are still equal and together form a worthy colorful continuum.

Locomotion training contributes to 6-month-old infants' mental rotation ability

This study investigated whether a locomotion training contributes to mental rotation performance in infants. Thirty 6-month-old pre-locomotor infants were randomly assigned to either a locomotion training or a control group which received no training. The general status of motor and cognitive development measured with the Bayley Scales did not differ between the 2 groups. Mental rotation was compared before and after the trainings using a mental rotation task in which infants were habituated to a rotating object and then tested with the same habituation object presented in a previously unseen angle and the corresponding mirror object. Results revealed that only infants in the locomotion training group showed a significant change in their looking durations at the test objects (habituation vs. mirror) in the mental rotation task. This suggests that self-produced locomotion experience can affect infants' mental rotation.

Gender difference in functional activity of 4-months-old infants during sleep: A functional near-infrared spectroscopy study

Sex differences emerge early in infancy. A number of earlier studies have investigated the resting-state network of infant sleep states, and there have been many studies using functional near-infrared spectroscopy (fNIRS) to examine the effects of infant language learning on changes in oxyhemoglobin and deoxyhemoglobin levels. However, studies examining sex differences from the resting-state network of infant sleep states are scarce. This study uses an open access dataset of task-free hemodynamic activity in 4-month-old infants during sleep by fNIRS, to identify some difference between male and female infants. We used Power Spectral Density showing at which frequencies the data variation/variance is high. We have also analyzed some gender differences by analyzing the relationship between individual channels, the degree of activation, etc. The results of this study showed that female and male infants had different Power Spectral Density for oxyhemoglobin and deoxyhemoglobin at rest, showing stronger differences at frontoparietal network, somatomotor network, visual network and dorsal network. This may be due to the differences in the timing or extent of development of those networks. These differences will provide some assistance in future studies of the early education of male and female infants.

Representations of Abstract Relations in Infancy

relations are considered the pinnacle of human cognition, allowing for analogical and logical reasoning, and possibly setting humans apart from other animal species. Recent experimental evidence showed that infants are capable of representing the abstract relations same and different, prompting the question of the format of such representations. In a propositional language of thought, abstract relations would be represented in the form of discrete symbols. Is this format available to pre-lexical infants? We report six experiments (N = 192) relying on pupillometry and investigating how preverbal 10- to 12-month-old infants represent the relation same. We found that infants' ability to represent the relation same is impacted by the number of individual entities taking part in the relation. Infants could represent that four syllables were the same and generalized that relation to novel sequences (Experiments 1 and 4). However, they failed to generalize the relation same when it involved 5 or 6 syllables (Experiments 2-3), showing that infants' representation of the relation same is constrained by the limits of working memory capacity. Infants also failed to form a representation equivalent to all the same, which could apply to a varying number of same syllables (Experiments 5-6). These results highlight important discontinuities along cognitive development. Contrary to adults, preverbal infants lack a discrete symbol for the relation same, and rather build a representation of the relation by assembling symbols for individual entities.

How 9-month-old crawling infants profit from visual-manual rotations in a mental rotation task

Studies show that visual-manual object exploration influences spatial cognition, and specifically mental rotation performance in infancy. The current work with 9-month-old infants investigated which specific exploration procedures (related to crawling experience) support mental rotation performance. In two studies, we examined the effects of two different exploration procedures, manual rotation (Study 1) and haptic scanning (Study 2), on subsequent mental rotation performance. To this end, we constrained infants' exploration possibilities to only one of the respective procedures, and then tested mental rotation performance using a live experimental set-up based on the task used by Moore and Johnson (2008). Results show that, after manual rotation experience with a target object, crawling infants were able to distinguish between exploration objects and their mirror objects, while non-crawling infants were not (Study 1). Infants who were given prior experience with objects through haptic scans (Study 2) did not discriminate between objects, regardless of their crawling experience. Results indicated that a combination of manual rotations and crawling experience are valuable for building up the internal spatial representation of an object.

Cultural Change Reduces Gender Differences in Mobility and Spatial Ability among Seminomadic Pastoralist-Forager Children in Northern Namibia

A fundamental cognitive function found across a wide range of species and necessary for survival is the ability to navigate complex environments. It has been suggested that mobility may play an important role in the development of spatial skills. Despite evolutionary arguments offering logical explanations for why sex/gender differences in spatial abilities and mobility might exist, thus far there has been limited sampling from nonindustrialized and subsistence-based societies. This lack of sampling diversity has left many unanswered questions regarding the effects that environmental variation and cultural norms may have in shaping mobility patterns during childhood and the development of spatial competencies that may be associated with it. Here we examine variation in mobility (through GPS tracking and interviews), performance on large-scale spatial skills (i.e., navigational ability), and performance on small-scale spatial skills (e.g., mental rotation task, Corsi blocks task, and water-level task) among Twa forager/pastoralist children whose daily lives have been dramatically altered since settlement and the introduction of government-funded boarding schools. Unlike in previous findings among Twa adults, boys and girls (N = 88; aged 6-18) show similar patterns of travel on all measures of mobility. We also find no significant differences in spatial task performance by gender for large- or small-scale spatial skills. Further, children performed as well as adults did on mental rotation, and they outperformed adults on the water-level task. We discuss how children's early learning environments may influence the development of both large- and small-scale spatial skills.

Men, women and STEM: Why the differences and what should be done?

It is a well-known and widely lamented fact that men outnumber women in a number of fields in STEM (science, technology, engineering and maths). The most commonly discussed explanations for the gender gaps are discrimination and socialization, and the most common policy prescriptions target those ostensible causes. However, a great deal of evidence in the behavioural sciences suggests that discrimination and socialization are only part of the story. The purpose of this paper is to highlight other aspects of the story: aspects that are commonly overlooked or downplayed. More precisely, the paper has two main aims. The first is to examine the evidence that factors other than workplace discrimination contribute to the gender gaps in STEM. These include relatively large average sex differences in career and lifestyle preferences, and relatively small average differences in cognitive aptitudes – some favouring males, others favouring females – which are associated with progressively larger differences the further above the average one looks. The second aim is to examine the evidence suggesting that these sex differences are not purely a product of social factors but also have a substantial biological (i.e. inherited) component. A more complete picture of the causes of the unequal sex ratios in STEM may productively inform policy discussions.

Influence of the stimulus material on gender differences in a mental-rotation test

Gender differences in mental-rotation tests with cube figures as rotational material are well examined and robust. Besides biological or socialization factors, task characteristics could partly be responsible for men's advantage in mental rotation. Therefore, we investigated in two studies the influence of different rotational materials on the gender differences in mental-rotation performance. In the first study, 134 undergraduate students (89 women, 45 men) participated using a mental-rotation test with either cube or pellet figures. Significant gender differences in favour of men but no interaction of gender and material were found. In the second study, 189 undergraduate students (110 women, 79 men) solved a mental-rotation test with either male or female-stereotyped objects. Significant gender differences appeared only when male-stereotyped objects were used as rotational material, but not for female-stereotyped material. A significant interaction of gender and material appeared. Hence, some rotational objects seem to have an influence on participants' mental-rotation performance and the gender differences in this task while others do not affect performances of women and men.

Spatial anxiety mediates the sex difference in adult mental rotation test performance

Mental rotation ability is associated with successful advances in STEM (science, technology, engineering, and mathematics) education and occupations. Meta-analyses have shown consistent sex disparities in mental rotation, where men outperform women on one measure of mental rotation ability, the Mental Rotations Test (MRT). Spatial anxiety, or the fear and apprehension felt when completing a task that requires spatial thinking, was proposed as a mechanism explaining the relation between sex and mental rotation test performance. This study modified the Spatial Anxiety Scale (SAS) to include questions about how anxious individuals feel when they must mentally rotate items to accomplish a task (e.g., playing Tetris). An exploratory factor analysis was conducted to assess the factorial structure of the modified spatial anxiety scale. Three factor loadings were extracted representing the ability to navigate, mentally rotate objects, and visualize objects. Furthermore, we analyzed the role of spatial anxiety and trait anxiety as potential mediators of the relation between participant sex and mental rotation performance. Spatial anxiety partially mediated the link between the sex of the participants and the MRT performance controlling for trait anxiety. Only navigation and mental rotation anxiety significantly mediated the relation between participant sex and mental rotation performance. We posit spatial anxiety as a barrier to efficient and accurate spatial thinking, and suggest that reducing spatial anxiety has the potential to improve spatial skills and reduce sex differences in mental rotation test performance. To ascertain this, an experimental design can determine whether a reduction in spatial anxiety causes changes in mental rotation test scores.

The development of mental rotation ability across the first year after birth

Mental rotation (MR) is the ability to imagine the appearance of an object from a different perspective. This ability is involved in many human cognitive and behavioral activities. We discuss studies that have examined MR in infants and its development across the first year after birth. Despite some conflicting findings across these studies, several conclusions can be reached. First, MR may be available to human infants as young as 3 months of age. Second, MR processes in infancy may be similar or identical to MR processes later in life. Third, there may be sex differences in MR performance, in general favoring males. Fourth, there appear to be multiple influences on infants' MR performance, including infants' motor activity, stimulus complexity, hormones, and parental attitudes. We conclude by calling for additional research to examine more carefully the causes and consequences of MR abilities early in life.

Spatial Thinking in Infancy: Origins and Development of Mental Rotation Between 3 and 10 Months of Age

Mental rotation (MR) is the ability to transform a mental representation of an object so as to accurately predict how the object would look from a different angle (Sci 171:701–703, 1971), and it is involved in a number of important cognitive and behavioral activities. In this review we discuss recent studies that have examined MR in infants and the development of MR across the first year after birth. These studies have produced many conflicting results, yet several tentative conclusions can be reached. First, MR may be operational in infants as young as 3 months of age. Second, there may be sex differences in MR performance in infancy, in general favoring males, as there are in children and in adults. Third, there appear to be multiple influences on infants’ MR performance, including infants’ motor activity, stimulus or task complexity, hormones, and parental attitudes. We conclude by calling for additional research to examine more carefully the causes and consequences of MR abilities early in life.

Cubes or Pellets in Mental-Rotation Tests: Effects on Gender Differences and on the Performance in a Subsequent Math Test

In mental rotation, males consistently outperform females in performance and confidence. Both can affect math anxiety. In the present study, 107 undergraduate students (85 female) solved a mental-rotation test either with cube (C-MRT) or pellet (P-MRT) figures as stimulus material, then reported their confidence in their ability in the test, and solved a math test. Males performed better than females in both test versions: In the C-MRT, with a large effect, and in the P-MRT, with a small effect, and reported higher scores in their confidence. In math test performance, males scored higher than females when they solved the math test after the C-MRT but not after the P-MRT. The interactions of gender and stimulus material were not significant. Correlations between confidence and math test performance were large for males and not significant for females. Stereotype threat and lift effects are discussed as possible reasons for the varying effects of the stimulus material on the MRT performance of male and female participants.

Sex Similarities and Differences in Intelligence in Children Aged Two to Eight: Analysis of SON-R 2-8 Scores

The aim of this study was to investigate sex similarities and differences in visuospatial and fluid abilities and IQ scores based on those abilities in children aged two to eight. Standardization data from the Snijders-Oomen Nonverbal Intelligence Test for Children aged 2-8 (SON-R 2-8) were used. A representative sample composed of 965 children from the Netherlands and 762 children from Germany was examined. Small but significant mean sex differences favoring girls were observed until age four. At ages six and seven, boys achieved similar cognitive development levels to girls regarding all abilities assessed and outperformed girls on the Mosaics subtest measuring visuospatial cognition. Boys also displayed higher variability rates in performance. The distribution of IQ scores, with the overrepresentation of girls scoring above mean and the overrepresentation of boys scoring below mean in early childhood, altered with age towards parity between the sexes. The results suggest that girls tend to mature earlier with respect to cognitive abilities. During the course of development, however, the differences between girls and boys may become negligible.

Sex Differences in Gains Among Hispanic Pre-kindergartners' Mental Rotation Skills

The current study explores change in mental rotation skills throughout the pre-kindergarten year in a Hispanic population to better understand the development of early sex differences in mental rotation. Ninety-six Hispanic children (M = 4 years 8 months) completed a mental rotation task at the beginning and end of pre-kindergarten. Results suggest Hispanic boys and girls differed in gains on mental rotation ability, with boys improving significantly more than girls during pre-kindergarten on a mental rotation task. This study highlights the significance of studying mental rotation abilities in a Hispanic population of pre-kindergarten aged children and suggests the importance of examining sex differences in mental rotation over time, rather than at one time-point, to better understand when sex differences in spatial skills develop. We discuss various factors that potentially affect the growth of spatial skills including the role of early education, spatial experiences, and spatial language input.

What makes a landmark effective in adolescent and adult rats? Sex and age differences in a navigation task

In three experiments, rats of different ages were trained in a circular pool to find a hidden platform whose location was defined in terms of a single landmark, a cylinder outside the pool. Following training, two main components of the landmark, its shape and pattern, were tested individually. Experiment 1 was performed by adolescent and adult rats (Exp. 1a, males; Exp. 1b, females). Adult rats always learned faster than the adolescent animals. On test trials, interesting tendencies were found-mainly, one favoring males on the shape test trial, and another favoring females on the pattern test trial. Experiment 2 was conducted only with adolescent rats, and these males and females did not differ when learning the task. However, on test trials the males learned more about the landmark shape component than about the landmark pattern component, while the females learned equally about the two components of the landmark. Finally, Experiment 3 was conducted only with adult rats, and again the males and females did not differ when learning the task. However, on test trials the males learned equally about the two components of the landmark (shape and pattern), but the females learned more about the landmark pattern component than about the landmark shape component. This set of experiments supports the claim that male and female rats can learn rather different things about a landmark that signals the location of the platform, with age being a critical variable.

Object exploration facilitates 4-month-olds' mental rotation performance

How do infants learn to mentally rotate objects, to imagine them rotating through different viewpoints? One possibility is that development of infants' mental rotation (MR) is facilitated by visual and manual experience with complex objects. To evaluate this possibility, eighty 4-month-olds (40 females, 40 males) participated in an object exploration task with Velcro "sticky mittens" that allow infants too young to grasp objects themselves to nonetheless explore those objects manually as well as visually. These eighty infants also participated in a visual habituation task designed to test MR. Half the infants (Mittens First group) explored the object prior to the MR task, and the other half afterwards (Mittens Second group), to examine the role of immediate prior object experience on MR performance. We compared performance of male and female infants, but found little evidence for sex differences. However, we found an important effect of object exploration: The infants in the Mittens First group who exhibited the highest levels of spontaneous object engagement showed the strongest evidence of MR, but there were no consistent correlations between these measures for infants in the Mittens Second group. These findings suggest an important contribution from object experience to development of MR.

Influence of sex-stereotyped stimuli on the mental-rotation performance of elderly persons

BACKGROUND

In mental-rotation tests with cube figures as rotational objects, differences in favor of men are often found (Voyer, Voyer, & Bryden, 1995). Mental-rotation performance often declines with age (Jacewicz & Hartley, 1987), but sex differences usually remain (Herman & Bruce, 1983).

METHODS

In this study, male- and female-stereotyped objects were used as rotational stimuli in a mental-rotation paper and pencil test (Ruthsatz, Neuburger, Rahe, Jansen, & Quaiser-Pohl, 2017) for elderly participants (age: 57-88 years).

RESULTS

Overall, no sex differences for mental-rotation performance were found, whereas a significant interaction of sex and stimulus material revealed better performance for own-sex objects (η² = .070). A significant negative correlation between mental-rotation performance and age could be found (r = -.384).

CONCLUSIONS

It seems to be easier to perform mental-rotation with objects that persons are more familiar with. There is a decrease in mental-rotation accuracy as well as in the processing speed for the older participants.

Impact of rotation angle on crawling and non-crawling 9-month-old infants' mental rotation ability

The current study investigated whether 9-month-old infants' mental rotation performance was influenced by the magnitude of the angle of object rotation and their crawling ability. A total of 76 infants were tested; of these infants, 39 had been crawling for an average of 9.0 weeks. Infants were habituated to a video of a simplified Shepard-Metzler object (Shepard & Metzler, 1971), always rotating forward through a 180° angle around the horizontal axis of the object. After habituation, in two different test conditions, infants were presented with test videos of the same object rotating farther forward through a previously unseen 90° angle and with a test video of its mirror image. The two test conditions differed in the magnitude of the gap between the end of the habituation rotations and the beginning of the test rotations. The gaps were 0° and 54°. The results revealed that the mental rotation performance was influenced by the magnitude of the gaps only for the crawling infants. Their response showed significant transition from a preference for the mirror object rotations toward a preference for the familiar habituation object rotations. Thus, the results provide first evidence that it is easier for 9-month-old crawling infants to mentally rotate an object along a small angle compared with a large one.

Adults’ Sex Difference in a Dynamic Mental Rotation Task

Abstract. With the Mental Rotation Test (MRT), large and reliable sex differences are found. Used with children younger than about 9 or 10 years, MRT performance is at chance level. Simpler tasks used with younger children have revealed inconclusive results. Moore and Johnson (2008 , 2011 ) observed sex differences in infants using a habituation task with 3D cube figures rotating back and forth in depth through a 240° angle. Thereafter, female infants treated similarly the original figure and a mirror-image cube figure presented revolving through the previously unseen 120° angle, whereas male infants behaved as if they recognized the familiar object. In the present study, 256 adults participated in the MRT as well as in a modified two-alternative forced-choice dynamic version of the infants’ task. Sex differences were present for both tasks. More importantly, there was a positive correlation in performance across both tasks for both women and men. Since the new task turned out to be simpler, it might be suitable also for children. We present the first, although indirect, evidence that the sex effects reported by Moore and Johnson might indeed reflect early sex differences in mental rotation.

Sample size, statistical power, and false conclusions in infant looking-time research

Infant research is hard. It is difficult, expensive, and time consuming to identify, recruit and test infants. As a result, ours is a field of small sample sizes. Many studies using infant looking time as a measure have samples of 8 to 12 infants per cell, and studies with more than 24 infants per cell are uncommon. This paper examines the effect of such sample sizes on statistical power and the conclusions drawn from infant looking time research. An examination of the state of the current literature suggests that most published looking time studies have low power, which leads in the long run to an increase in both false positive and false negative results. Three data sets with large samples (>30 infants) were used to simulate experiments with smaller sample sizes; 1000 random subsamples of 8, 12, 16, 20, and 24 infants from the overall samples were selected, making it possible to examine the systematic effect of sample size on the results. This approach revealed that despite clear results with the original large samples, the results with smaller subsamples were highly variable, yielding both false positive and false negative outcomes. Finally, a number of emerging possible solutions are discussed.

Explaining the sex difference in dyslexia

BACKGROUND

Males are diagnosed with dyslexia more frequently than females, even in epidemiological samples. This may be explained by greater variance in males' reading performance.

METHODS

We expand on previous research by rigorously testing the variance difference theory, and testing for mediation of the sex difference by cognitive correlates. We developed an analytic framework that can be applied to group differences in any psychiatric disorder.

RESULTS

Males' overrepresentation in the low performance tail of the reading distribution was accounted for by mean and variance differences across sex. There was no sex difference at the high performance tail. Processing speed (PS) and inhibitory control partially mediated the sex difference. Verbal reasoning emerged as a strength in males.

CONCLUSIONS

Our results complement a previous finding that PS partially mediates the sex difference in symptoms of attention deficit/hyperactivity disorder (ADHD), and helps explain the sex difference in both dyslexia and ADHD and their comorbidity.

Mobility and Navigation among the Yucatec Maya: Sex Differences Reflect Parental Investment, Not Mating Competition

Sex differences in range size and navigation are widely reported, with males traveling farther than females, being less spatially anxious, and in many studies navigating more effectively. One explanation holds that these differences are the result of sexual selection, with larger ranges conferring mating benefits on males, while another explanation focuses on greater parenting costs that large ranges impose on reproductive-aged females. We evaluated these arguments with data from a community of highly monogamous Maya farmers. Maya men and women do not differ in distance traveled over the region during the mate-seeking years, suggesting that mating competition does not affect range size in this monogamous population. However, men’s regional and daily travel increases after marriage, apparently in pursuit of resources that benefit families, whereas women reduce their daily travel after marriage. This suggests that parental effort is more important than mating effort in this population. Despite the relatively modest overall sex difference in mobility, Maya men were less spatially anxious than women, thought themselves to be better navigators, and pointed more accurately to distant locations. A structural equation model showed that the sex by marital status interaction had a direct effect on mobility, with a weaker indirect effect of sex on mobility mediated by navigational ability.

Seeing double: 5-month-olds' mental rotation of dynamic, 3D block stimuli presented on dual monitors

Mental rotation (MR) involves the ability to predict how an object will look once it has been rotated into a new orientation in space. To date, studies of MR in infants have tested this ability using abstract stimuli presented using a single display. Evidence from existing studies suggests that using multiple displays may affect an infant's performance in some kinds of MR tasks. This study used Moore & Johnson's (2008) simplified Shepard-Metzler objects in a dual-monitor MR task presented to five-month-old infants. Evidence for MR in infancy was found. These findings have implications for MR testing in infancy and the influence of display properties on infant MR performance.

The contribution of the androgen receptor (AR) in human spatial learning and memory: A study in women with complete androgen insensitivity syndrome (CAIS)

Few studies have examined the impact of androgen insensitivity on human spatial learning and memory. In the present study, we tested 11 women with complete androgen insensitivity syndrome (CAIS), a rare genetic disorder characterized by complete absence of AR activity, and compared their performance against 20 comparison males and 19 comparison females on a virtual analog of the Morris Water Maze task. The results replicated a main sex effect showing that men relative to women were faster in finding the hidden platform and had reduced heading error. Furthermore, findings indicated that mean performance of women with CAIS was between control women and control men, though the differences were not statistically significant. Effect size estimates (and corresponding confidence intervals) of spatial learning trials showed little difference between women with CAIS and control women but CAIS women differed from men, but not women, on two variables, latency to find the platform and first-move latency. No differences between groups were present during visible platform trials or the probe trial, a measure of spatial memory. Moreover, groups also did not differ on estimates of IQ and variability of performance. The findings are discussed in relation to androgen insensitivity in human spatial learning and memory.

An early sex difference in the relation between mental rotation and object preference

Accumulating evidence suggests that males outperform females on mental rotation tasks as early as infancy. Sex differences in object preference have also been shown to emerge early in development and precede sex-typed play in childhood. Although research with adults and older children is suggestive of a relationship between play preferences and visuospatial abilities, including mental rotation, little is known about the developmental origins of this relationship. The present study compared mental rotation ability and object preference in 6- to 13-month-old infants. We used a novel paradigm to examine individual differences in infants’ mental rotation abilities as well as their differential preference for one of two sex-typed objects. A sex difference was found on both tasks, with boys showing an advantage in performance on the mental rotation task and exhibiting greater visual attention to the male-typed object (i.e., a toy truck) than to the female-typed object (i.e., a doll) in comparison to girls. Moreover, we found a relation between mental rotation and object preference that varied by sex. Greater visual interest in the male-typed object was related to greater mental rotation performance in boys, but not in girls. Possible explanations related to perceptual biases, prenatal androgen exposure, and experiential influences for this sex difference are discussed.

Developmental interventions to address the STEM gender gap: exploring intended and unintended consequences

Women and girls in the United States continue to be underrepresented in STEM, particularly in engineering and technology fields. This gap has been attracting recent attention from those motivated to ensure that girls and women have access to a full range of personally satisfying careers as well as from those concerned with developing a rich talent pool to meet national workforce needs. This chapter is focused on interventions that have been designed to address this STEM gender gap. We begin by documenting the STEM gender gap and then review change mechanisms emerging from theories of gender development that may be harnessed in intervention efforts. In addition, we pro vide a taxonomy of intervention goals which we then use to organize an illustrative review of sample interventions. After commenting on some of the findings and limitations of past work, we offer suggestions for enhancing the systematic evaluation of intervention programs that include careful selection of comparison groups, a broad array of STEM outcome measures, assessment of potentially unintended consequences, and meta-analyses.

Progesterone and mental rotation task: is there any effect?

Mental rotation task (MRT) incorporates elements of spatial abilities, important in many professions, with people of both genders involved. Importantly, these are the areas where spatial tasks might be performed for long time periods; thus adverse effects of mental fatigue are highly unwanted. Substantial variation of MRT performance in relation to estrogen levels has been observed in many studies, whereas the role of progesterone remains elusive. Here we aimed to elucidate the effect of progesterone level on the long-duration (1.5 hours) performance of MRT. We included three groups of subjects: a group of males as a control, a group of females in their follicular phase (low progesterone) and a group of females in their luteal phase (high progesterone), MRT accuracy and response time, subjective fatigue ratings and cardiovascular measures together with 17 β -estradiol and progesterone concentrations were analyzed. We found that subjective ratings of fatigue increased, performance accuracy increased, and mean response times decreased during the task in all groups. Females in luteal phase were significantly slower not only than men, but also than females in their follicular phase. An increase in subjective fatigue ratings was positively related to progesterone level-at higher progesterone levels, females felt more tired.