Children’s Computation of Complex Linguistic Forms: A Study of Frequency and Imageability Effects

This study investigates the storage vs. composition of inflected forms in typically-developing children. Children aged 8–12 were tested on the production of regular and irregular past-tense forms. Storage (vs. composition) was examined by probing for past-tense frequency effects and imageability effects – both of which are diagnostic tests for storage – while controlling for a number of confounding factors. We also examined sex as a factor. Irregular inflected forms, which must depend on stored representations, always showed evidence of storage (frequency and/or imageability effects), not only across all children, but also separately in both sexes. In contrast, for regular forms, which could be either stored or composed, only girls showed evidence of storage. This pattern is similar to that found in previously-acquired adult data from the same task, with the notable exception that development affects which factors influence the storage of regulars in females: imageability plays a larger role in girls, and frequency in women. Overall, the results suggest that irregular inflected forms are always stored (in children and adults, and in both sexes), whereas regulars can be either composed or stored, with their storage a function of various item- and subject-level factors.

Autism affects different parts of the brain in women and men

Autism affects different parts of the brain in females with autism than males with autism, a new study reveals. The research is published today in the journal Brain as an open-access article.

Scientists at the Autism Research Centre at the University of Cambridge used magnetic resonance imaging to examine whether autism affects the brain of males and females in a similar or different way. They found that the anatomy of the brain of someone with autism substantially depends on whether an individual is male or female, with brain areas that were atypical in adult females with autism being similar to areas that differ between typically developing males and females. This was not seen in men with autism.

“One of our new findings is that females with autism show neuroanatomical ‘masculinization’,” said Professor Simon Baron-Cohen, senior author of the paper. “This may implicate physiological mechanisms that drive sexual dimorphism, such as prenatal sex hormones and sex-linked genetic mechanisms.”

Autism affects 1% of the general population and is more prevalent in males. Most studies have therefore focused on male-dominant samples. As a result, our understanding of the neurobiology of autism is male-biased.

“This is one of the largest brain imaging studies of sex/gender differences yet conducted in autism. Females with autism have long been under-recognized and probably misunderstood,” said Dr Meng-Chuan Lai, who led the research project. “The findings suggest that we should not blindly assume that everything found in males with autism applies to females. This is an important example of the diversity within the ‘spectrum’.”

Dr Michael Lombardo, who co-led the study, added that although autism manifests itself in many different ways, grouping by gender may help provide a better understanding of this condition.

He said: “Autism as a whole is complex and vastly diverse, or heterogeneous, and this new study indicates that there are ways to subgroup the autism spectrum, such as whether an individual is male or female. Reducing heterogeneity via subgrouping will allow research to make significant progress towards understanding the mechanisms that cause autism.”

Males’ superior spatial ability likely is not an evolutionary adaptation

Males and females differ in a lot of traits (besides the obvious ones) and some evolutionary psychologists have proposed hypotheses to explain why. Some argue, for example, that males’ slight, but significant, superiority in spatial navigation over females – a phenomenon demonstrated repeatedly in many species, including humans – is probably “adaptive,” meaning that over the course of evolutionary history the trait gave males an advantage that led them to have more offspring than their peers.

A new analysis published in The Quarterly Review of Biology found no support for this hypothesis. The researchers, led by University of Illinois psychology professor Justin Rhodes, looked at 35 studies that included data about the territorial ranges and spatial abilities of 11 species of animals: cuttlefish, deer mice, horses, humans, laboratory mice, meadow voles, pine voles, prairie voles, rats, rhesus macaques and talastuco-tucos (a type of burrowing rodent). Rhodes and his colleagues found that in eight out of 11 species, males demonstrated moderately superior spatial skills to their female counterparts, regardless of the size of their territories or the extent to which males ranged farther than females of the same species.

The findings lend support to an often-overlooked hypothesis, Rhodes said. The average superiority of males over females in spatial navigation may just be a “side effect” of testosterone, he said. (Previous studies have shown that women who take testosterone tend to see an improvement in their spatial navigation skills, he said.)

The analysis adds a new dimension to an ongoing debate about the evolutionary significance of some baffling human traits. Rhodes and his colleagues object to “creation stories” that seek to explain sexual phenomena like the female orgasm, rape or menopause by hypothesizing that they evolved because they provided an evolutionary advantage. Some evolutionary psychologists describe rape, for example, as an alternate mating strategy for males who otherwise are reproductively unsuccessful. Others say menopause evolved in women to enhance the survival of their genes by increasing the time spent nurturing their grandchildren. Some of these hypotheses seem intuitive, Rhodes said. “But these stories generally are not testable.”

Researchers tend to overlook the fact that many physical and behavioral traits arise as a consequence of random events, or are simply side effects of other changes that offer real evolutionary advantages, he said.

“For example, women have nipples because it’s an adaptation; it promotes the survival of their offspring,” Rhodes said. “Men get it because it doesn’t harm them. So if we see something that’s advantageous for one sex, the other sex will get it because it’s inheriting the same genes – unless it’s bad for that sex.”

Similarly, scientists who claim that the different spatial skills in men and women are adaptive must explain why women failed to inherit the superior spatial skills of their navigationally enhanced fathers, Rhodes said.

“The only way you will get a sex difference (in an adaptive trait) is where a trait is good for one sex and bad for the other,” he said. “But how is navigation bad for women? This is a flaw in the logic.”

“When people hear arguments made or stories told, particularly about human behaviors being products of adaptation, I think they should ask the question: ‘Where is the evidence?’ ” Rhodes said.

Language Protein Differs in Males, Females

Male rat pups have more of a specific brain protein associated with language development than females, according to a study published February 20 in The Journal of Neuroscience. The study also found sex differences in the brain protein in a small group of children. The findings may shed light on sex differences in communication in animals and language acquisition in people.

Sex differences in early language acquisition and development in children are well documented — on average, girls tend to speak earlier and with greater complexity than boys of the same age. However, scientists continue to debate the origin and significance of such differences. Previous studies showed the Foxp2 protein plays an important role in speech and language development in humans and vocal communication in birds and other mammals.

In the current study, J. Michael Bowers, PhD, Margaret McCarthy, PhD, and colleagues at the University of Maryland School of Medicine examined whether sex differences in the expression of the Foxp2 protein in the developing brain might underlie communication differences between the sexes.

The researchers analyzed the levels of Foxp2 protein in the brains of four-day-old female and male rats and compared the ultrasonic distress calls made by the animals when separated from their mothers and siblings. Compared with females, males had more of the protein in brain areas associated with cognition, emotion, and vocalization. They also made more noise than females — producing nearly double the total vocalizations over the five-minute separation period — and were preferentially retrieved and returned to the nest first by the mother.

When the researchers reduced levels of the Foxp2 protein in the male pups and increased it in female pups, they reversed the sex difference in the distress calls, causing males to sound like females and the females like males. This change led the mother to reverse her behavior as well, preferentially retrieving the females over the males.

“This study is one of the first to report a sex difference in the expression of a language-associated protein in humans or animals,” McCarthy said. “The findings raise the possibility that sex differences in brain and behavior are more pervasive and established earlier than previously appreciated.”

The researchers extended their findings to humans in a preliminary study of Foxp2 protein in a small group of children. Unlike the rats, in which Foxp2 protein was elevated in males, they found that in humans, the girls had more of the Foxp2 protein in the cortex — a brain region associated with language — than age-matched boys.

“At first glance, one might conclude that the findings in rats don’t generalize to humans, but the higher levels of Foxp2 expression are found in the more communicative sex in each species,” noted Cheryl Sisk, who studies sex differences at Michigan State University and was not involved with the study.

Men and women explore the visual world differently

Everyone knows that men and women tend to hold different views on certain things. However, new research by scientists from the University of Bristol and published in PLoS ONE indicates that this may literally be the case.
Researchers examined where men and women looked while viewing still images from films and pieces of art. They found that while women made fewer eye movements than men, those they did make were longer and to more varied locations.

These differences were largest when viewing images of people. With photos of heterosexual couples, both men and women preferred looking at the female figure rather than the male one. However, this preference was even stronger for women.

While men were only interested in the faces of the two figures, women’s eyes were also drawn to the rest of the bodies - in particular that of the female figure.

Felix Mercer Moss, PhD student in the Department of Computer Science who led the study, said: “The study represents the most compelling evidence yet that, despite occupying the same world, the viewpoints of men and women can, at times, be very different.

“Our findings have important implications for both past and future eye movement research together with future technological applications.”

Women are better than men at recognizing living things and men are better than women at recognizing vehicles.

That is the unanticipated result of an analysis Vanderbilt psychologists performed on data from a series of visual recognition tasks collected in the process of developing a new standard test for expertise in object recognition.

“These results aren’t definitive, but they are consistent with the following story,” said Gauthier. “Everyone is born with a general ability to recognize objects and the capability to get really good at it. Nearly everyone becomes expert at recognizing faces, because of their importance for social interactions. Most people also develop expertise for recognizing other types of objects due to their jobs, hobbies or interests. Our culture influences which categories we become interested in, which explains the differences between men and women.”

The results were published online on Aug. 3 in the Vision Research journal in an article titled, “The Vanderbilt Expertise Test Reveals Domain-General and Domain-Specific Sex Effects in Object Recognition.”

New research finds that the way that the visual centers of men and women’s brains works is different. Men have greater sensitivity to fine detail and rapidly moving stimuli, but women are better at discriminating between colors.