Older news items (pre-2010) brought over from the old website
Gender gap in math is culture-based
Data from the Trends in International Mathematics and Science Study and the Programme for International Student Assessment, representing 493,495 students ages 14-16 from 69 countries, have revealed only very small gender differences overall, but marked variation when nations are compared. For example, there are more girls in the top tier in countries such as Iceland, Thailand, and the United Kingdom–and even in certain U.S. populations, such as Asian-Americans. However, despite overall similarities in math skills, boys felt significantly more confident in their abilities than girls did and were more motivated to do well. Furthermore, although some studies have found more males than females scoring above the 95th or 99th percentile, this gender gap has significantly narrowed over time in the U.S. and is not found among some ethnic groups and in some nations. Greater male variability with respect to mathematics, where it exists, correlates with several measures of gender inequality.
 Gender, culture, and mathematics performance.
Proceedings of the National Academy of Sciences. 106(22), 8801 - 8807.
Else-Quest, N.M., Hyde, J.S. & Linn, M.C. 2010. Cross-national patterns of gender differences in mathematics: A meta-analysis. Psychological Bulletin, 136(1), 103-127.
Positive stereotypes can offset negative stereotype effect
A number of studies have now shown that negative stereotypes can impair cognitive performance, mainly through adding to working memory load. A new study has now shown that this effect can be mitigated by the activation of a positive stereotype. The research takes advantage of the fact that we all belong to several social groups. In this case, the relevant groups were ‘female’ and ‘college student’. As usual, when (subtly) reminded of negative stereotypes for women and math, women performed worse. The interesting thing was that this didn’t happen if women were also made aware that college students performed better at math than non-college students. Moreover, this was reflected in working memory capacity. It seems that, when both a positive and a negative stereotype are offered, people will tend to choose the positive stereotype, and the effects of this will cancel out the negative stereotype. It’s also worth noting how easily these stereotypes are activated: effects could be manipulated simply by subtly changing demographic questions asked before the test (and it is not uncommon that test-takers are first required to answer some demographic questions).
 Multiple social identities and stereotype threat: Imbalance, accessibility, and working memory..
Journal of Personality and Social Psychology. 96(5), 949 - 966.
Sex difference on spatial skill test linked to brain structure
It’s been well established that men (as a group) consistently out-perform women on spatial tasks. Research has also established that the parietal lobes in women tend to have proportionally more gray matter. Now a new study shows that the thicker cortex in the parietal lobe in women is associated with poorer mental rotation ability. It also reveals that the surface area of the parietal lobe is increased in men, compared to women, and this is directly related to better performance on mental rotation tasks. It also appears that, perhaps because the brain structure is different between men and women, the way the brain performs the task is different. While men appear able to globally rotate an object in space, women seem to do it piecemeal.
 Sex differences in parietal lobe morphology: Relationship to mental rotation performance.
Brain and Cognition. 69(3), 451 - 459.
Gender gap in spatial skills starts in infancy
On their own, the findings reported above do not answer the question of whether gender differences in spatial ability are biological or cultural, as differences in brain structure and performance can be caused by different experiences during childhood. However, research has repeatedly found a gender difference in mental rotation in children four years and older, and now a new study has found evidence that male superiority in mental rotation is present in infants as young as 5 months old.
 Mental rotation in human infants: a sex difference.
Psychological Science: A Journal of the American Psychological Society / APS. 19(11), 1063 - 1066.
Gender differences in memory
A series of experiments looking at memory performance in men and women has revealed that women did better at verbal episodic memory tasks, such as remembering words, objects, pictures or everyday events, and men outperformed women in remembering symbolic, non-linguistic information, known as visuospatial processing. But women were again better on tasks that require both verbal and visuospatial processing, such as remembering the location of car keys. Women were also better at remembering faces, especially female faces. They also remembered androgynous faces presented as female more accurately than the androgynous faces presented as male, suggesting the reason is that women pay more attention to female than to male faces. Women also performed better than men in tasks requiring little to no verbal processing, such as recognition of familiar odors. But environmental factors, such as education, seem to influence the magnitude of these sex differences.
 Sex Differences in Episodic Memory.
Current Directions in Psychological Science. 17(1), 52 - 56.
Review supports mild memory impairment in pregnancy
A review of 14 studies testing the memory performances of more than 1,000 pregnant women, mothers and non-pregnant women, has found that pregnant women performed significantly worse on some, but not all aspects of the test. The hardest tests for the pregnant women were those that involved new or demanding tasks. Regular, well-practiced memory tasks were unlikely to be affected. The impairment wasn’t large — comparable to the modest deficits you'd find when comparing healthy 20-year-olds with healthy 60-year-olds. However, the impairment was sometimes still evident a year after birth (none looked beyond that point).
 A review of the impact of pregnancy on memory function.
Journal of Clinical and Experimental Neuropsychology. 29(8), 793 - 793.
Stereotype-induced math anxiety robs women's working memory
Another study finds evidence that being told men are better at mathematics undermines women's math performance, and extends it by demonstrating that the anxiety induced by the stereotype mainly reduced the verbal part of working memory, and that this carried over to subsequent (non-math-related) tasks. The accuracy of women exposed to the stereotype was reduced from nearly 90% in a pretest to about 80% after being told men do better in mathematics. Among women not receiving that message, performance actually improved slightly.
 Stereotype Threat and Working Memory: Mechanisms, Alleviation, and Spillover.
Journal of Experimental Psychology: General. 136(2), 256 - 276.
Gender differences in the brain
Results from an extremely large internet survey looking at sex-linked cognitive abilities, personality traits, interests, sexual attitudes and behavior, as well as physical traits, has found that cognitive abilities decline with age more steeply in men than in women. This effect is independent of sexual orientation. Differences in specific cognitive abilities were also found that did depend on sexual orientation as well as gender. Men scored higher than women on tests of mental rotation and the ability to judge line angles, whereas women scored higher than men on tests of object location memory and word fluency. However, homosexual men's visual-spatial abilities were, on average, lower than those of heterosexual men, and lesbian women's visual-spatial abilities were higher than those of heterosexual women.
 Gender and sexual orientation differences in cognition across adulthood: age is kinder to women than to men regardless of sexual orientation.
Archives of Sexual Behavior. 36(2), 235 - 249.
 Visuospatial performance on an internet line judgment task and potential hormonal markers: sex, sexual orientation, and 2D:4D.
Archives of Sexual Behavior. 36(2), 177 - 192.
 The Effects of Sex, Sexual Orientation, and Digit Ratio (2D:4D) on Mental Rotation Performance.
Archives of Sexual Behavior. 36(2), 251 - 260.
Sex and prenatal hormones affect cognitive performance
A study involving rhesus macaque monkeys has found that the tendency to use landmarks for navigation is typical only of females. In a situation where they had to navigate an open area to locate highly valued food items in goal boxes, gender or prenatal treatment did not affect how well the monkeys did when both spatial and marker cues were available. When landmarks directly indicated the correct locations but spatial information was unreliable, females performed better than males. Moreover, males whose testosterone exposure had been blocked early in gestation were more able to use the landmarks to navigate than normal males.
 Cognitive performance in rhesus monkeys varies by sex and prenatal androgen exposure.
Hormones and Behavior. 51(4), 496 - 507.
Implicit stereotypes and gender identification may affect female math performance
Relatedly, another study has come out showing that women enrolled in an introductory calculus course who possessed strong implicit gender stereotypes, (for example, automatically associating "male" more than "female" with math ability and math professions) and were likely to identify themselves as feminine, performed worse relative to their female counterparts who did not possess such stereotypes and who were less likely to identify with traditionally female characteristics. Strikingly, a majority of the women participating in the study explicitly expressed disagreement with the idea that men have superior math ability, suggesting that even when consciously disavowing stereotypes, female math students are still susceptible to negative perceptions of their ability.
 Implicit stereotypes, gender identification, and math-related outcomes: a prospective study of female college students.
Psychological Science: A Journal of the American Psychological Society / APS. 18(1), 13 - 18.
Women's math performance affected by theories on sex differences
In a salutary reminder to all researchers into gender and race differences, researchers found that women who received a genetic explanation for female underachievement in math or were reminded of the stereotype about female math underachievement, performed more poorly on math tests than those who received an experiential explanation (such as math teachers treating boys preferentially during the first years of math education) or were led to believe there are no sex differences in math.
 Exposure to Scientific Theories Affects Women's Math Performance.
Science. 314(5798), 435 - 435.
Memory problems at menopause
Findings from a study of 24 women approaching menopause have confirmed an earlier study involving over 800 women that found such women are no more likely than anyone else to suffer from memory retrieval problems. However, they did find that the women who complained more about problems with forgetfulness had a harder time learning or "encoding" new information, although they didn’t have actually have an impaired ability to learn new information. Although a larger study is needed to explore this link in more detail, the researchers suggest that stress and emotional upheaval may be responsible for attention failures that mean information isn’t encoded. The researchers did find that most of the women in their study had some sort of mood distress, including symptoms of depression or anxiety (note that this was not a random group, but women who were worried about their memory).
The study was reported at the annual meeting of the International Neuropsychological Society in Boston.
Brain size does matter, but differently for men and women
A study involving the intelligence testing of 100 neurologically normal, terminally ill volunteers, who agreed that their brains be measured after death, found that a bigger brain size is correlated with higher intelligence in certain areas, but there are differences between women and men. Verbal intelligence was clearly correlated with brain size, accounting for 36% of the verbal IQ score, for women and right-handed men — but not for left-handed men. Spatial intelligence was also correlated with brain size in women, but much less strongly, while it was not related at all to brain size in men. It may be that the size or structure of specific brain regions is related to spatial intelligence in men. Brain size decreased with age in men over the age span of 25 to 80 years, suggesting that the well-documented decline in visuospatial intelligence with age is related, at least in right-handed men, to the decrease in cerebral volume with age. However age hardly affected brain size in women.
 Intelligence and brain size in 100 postmortem brains: sex, lateralization and age factors.
Brain: A Journal of Neurology. 129(Pt 2), 386 - 398.
Effect of pregnancy on cognition depends on fetal gender
An intriguing new study may shed light on the conflicting results reported regarding the effect of pregnancy on cognition. The study, which tracked women throughout pregnancy through to postnatal resumption of menstruation, found that there was a significant effect of the sex of the baby on working memory and spatial ability. Women pregnant with boys consistently outperformed women pregnant with girls on these tests.
 Selective and persistent effect of foetal sex on cognition in pregnant women.
Neuroreport. 16(7), 779 - 782.
Cognitive effects of binge drinking worse for women
A new study looked at the cognitive effects of binge drinking, which apparently is on the rise in several countries, including Britain and the US. The study involved 100 healthy moderate-to-heavy social drinkers aged between 18 and 30. There were equal numbers of males and females. The study found that female binge drinkers performed worse on the working-memory and vigilance tasks than did the female non-binge drinkers.
 Binge Drinking, Cognitive Performance and Mood in a Population of Young Social Drinkers.
Alcoholism: Clinical and Experimental Research. 29(3), 317 - 325.
The effects of training and age on the spatial-memory gender gap
A study of 90 adult rhesus monkeys found young-adult males had better spatial memory than females, but peaked early. By old age, male and female monkeys had about the same performance. This finding is consistent with reports suggesting that men show greater age-related cognitive decline relative to women. A second study of 22 rhesus monkeys showed that in young adulthood, simple spatial-memory training did not help males but dramatically helped females, raising their performance to the level of young-adult males and wiping out the gender gap.
 Sex, Age, and Training Modulate Spatial Memory in the Rhesus Monkey (Macaca mulatta)..
Behavioral Neuroscience. 119(1), 118 - 126.
Faster neuron transmission in young males
A study of 186 male and 201 female students (aged 18-25) has found that men's brain cells can transmit nerve impulses 4% faster than women's, probably due to the faster increase of white matter in the male brain during adolescence.
 Confirmation of correlation between brain nerve conduction velocity and intelligence level in normal adults.
Intelligence. 32(6), 563 - 572.
IQ-related brain areas may differ in men and women
An imaging study of 48 men and women between 18 and 84 years old found that, although men and women performed equally on the IQ tests, the brain structures involved in intelligence appeared distinct. Compared with women, men had more than six times the amount of intelligence-related gray matter, while women had about nine times more white matter involved in intelligence than men did. Women also had a large proportion of their IQ-related brain matter (86% of white and 84% of gray) concentrated in the frontal lobes, while men had 90% of their IQ-related gray matter distributed equally between the frontal lobes and the parietal lobes, and 82% of their IQ-related white matter in the temporal lobes. The implications of all this are not clear, but it is worth noting that the volume of gray matter can increase with learning, and is thus a product of environment as well as genes. The findings also demonstrate that no single neuroanatomical structure determines general intelligence and that different types of brain designs are capable of producing equivalent intellectual performance.
 The neuroanatomy of general intelligence: sex matters.
NeuroImage. 25(1), 320 - 327.
Estrogen combines with stress to impair memory
A rat study has found that male and female rats performed equally well on a task involving the prefrontal cortex when under no stress, and when highly stressed, both made significant memory errors. But importantly, after exposure to a moderate level of stress, females were impaired, but males were not. When investigated further, it was found that female rats only showed this sensitivity when they were in a high-estrogen phase of their estrus cycle. The estrogen effect was confirmed in a further study using female rats who had had their ovaries removed, thus enabling the researchers to compare the effects of estrogen versus a placebo. These results suggest that high levels of estrogen can act to enhance the stress response, causing greater stress-related cognitive impairments, while providing reassurance that estrogen appears to have no effect on cognitive performance under non-stressful conditions.
 Estrogen mediates sex differences in stress-induced prefrontal cortex dysfunction.
Mol Psychiatry. 9(5), 531 - 538.
No support for idea that pregnancy affects memory and concentration
A study of pregnant women found many agreed with the popular view that pregnancy affects your memory. However, mental tests during pregnancy and after the birth found no difference between the performance of women who were pregnant and those who were not. It was possible that the affects are too mild to be picked up by the tests, or that the fatigue commonly experienced by women during pregnancy and early motherhood leads women to believe that their memory and concentration are affected.
The research was presented at the British Psychological Society annual conference in Bournemouth.
Women better at recognizing female but not male faces
Women’s superiority in face recognition tasks appears to be due to their better recognition of female faces. There was no difference between men and women in the recognition of male faces.
 Sex differences in face recognition--Women's faces make the difference.
Brain and Cognition. 50(1), 121 - 128.
Why women better remember emotional memories
A new brain imaging study reveals gender differences in the encoding of emotional memories. We have long known that women are better at remembering emotional memories, now we can see that the sexes tend to encode emotional experiences in different parts of the brain. In women, it seems that evaluation of emotional experience and encoding of the memory is much more tightly integrated.
 Sex differences in the neural basis of emotional memories.
Proceedings of the National Academy of Sciences of the United States of America. 99(16), 10789 - 10794.
Gender differences in frontal lobe neuron density
A recent study has found that women have up to 15% more brain cell density in the frontal lobe, which controls so-called higher mental processes, such as judgement, personality, planning and working memory. However, as they get older, women appear to shed cells more rapidly from this area than men. By old age, the density is similar for both sexes. It is not yet clear what impact, if any, this difference has on performance.
Witelson, S.F., Kigar, D.L. & Stoner-Beresh, H.J. 2001. Sex difference in the numerical density of neurons in the pyramidal layers of human prefrontal cortex: a stereologic study. Paper presented to the annual Society for Neuroscience meeting in San Diego, US.
Gender differences in neural networks underlying beginning reading
A recent study uses EEG readings to investigate gender differences in the emerging connectivity of neural networks associated with phonological processing, verbal fluency, higher-level thinking and word retrieval (skills needed for beginning reading), in preschoolers. The study confirms different patterns of growth in building connections between boys and girls. These differences point to the different advantages each gender brings to learning to read. Boys favor vocabulary sub-skills needed for comprehension while girls favor fluency and phonic sub-skills needed for the mechanics of reading.
Hanlon, H. 2001. Gender Differences Observed in Preschoolers’ Emerging Neural Networks. Paper presented at Genomes and Hormones: An Integrative Approach to Gender Differences in Physiology, an American Physiological Society (APS) conference held October 17-20 in Pittsburgh.
Boys' and girls' brains process faces differently
Previous research has suggested a right-hemisphere superiority in face processing, as well as adult male superiority at spatial and non-verbal skills (also associated with the right hemisphere of the brain). This study looked at face recognition and the ability to read facial expressions in young, pre-pubertal boys and girls. Boys and girls were equally good at recognizing faces and identifying expressions, but boys showed significantly greater activity in the right hemisphere, while the girls' brains were more active in the left hemisphere. It is speculated that boys tend to process faces at a global level (right hemisphere), while girls process faces at a more local level (left hemisphere). This may mean that females have an advantage in reading fine details of expression. More importantly, it may be that different treatments might be appropriate for males and females in the case of brain injury.
 Sex-related differences in event-related potentials, face recognition, and facial affect processing in prepubertal children.
Neuropsychology. 15(3), 329 - 341.
More women than men do well on memory tests in old age
Researchers from Leiden University tested the mental functioning of 599 Dutch men and women aged 85 years. Good mental speed on word and number recognition tests was found in 33% of the women and 28% of the men. Forty one per cent of the women and 29% of the men had a good memory. This despite the fact that significantly more of the women had limited formal education compared to the men (not surprising given the time in which they grew up). The authors suggested that biological differences - such as the relative absence of cardiovascular disease in elderly women compared with men of the same age - could account for these sex differences in mental decline.
 Cognitive function in the oldest old: women perform better than men.
Journal of Neurology, Neurosurgery & Psychiatry. 71(1), 29 - 32.