The following short summary is an excerpt from the National Association for Single-Sex Public Education
Studies of Male and Female Brains Show Differences in Structure, Function
In the past ten years or so, there has been an explosion of research into human brain chemistry and development. For the first time scientists are able to use equipment such as Magnetic Resonance Imaging (MRIs) and ultrasound testing to observe the brain in action and to better understand its development in childhood.
The research, summarized below, indicates that there are surprising differences between female and male brains, not only in design and structure but also in function. This has implications for the field of education, because it shows that boys and girls think and learn in different ways.
Male and female brains are different even before birth. Although every human fetus begins as a girl, a burst of male hormones during the 18 to 26th week of pregnancy interacting with aromatase enzymes causes irreparable and irreversible changes to the brain of the fetus. These male hormones transform it into a male brain that has different characteristics than the female version. Israeli scientists Reuwen and Anat Achiron discovered that they could distinguish female and male brains by using ultrasound techniques during the fifth month of pregnancy. Another research group from the University of Lausanne in Switzerland found that sex differences in babies' brain structure was so evident you can tell a boy's brain from a girl's just by looking at it with the naked eye.
It is impossible to change a boy's brain into a girl's, even through drastic methods such as castration. For example, consider the strange case of the Reimer boys, male identical twins born in 1965. After a botched-up circumcism, one twin no longer had a penis. Doctors advised his parents to raise him as a girl, and they did. "David" never truly became "Brenda". She never found acceptance by boys or girls at school. Despite dressing as a female, her interests and mannerisms were masculine. When Brenda was twenty, she became "David Reimer" again. Although David married and adopted children, he remained despondent, committing suicide when he was only thirty-eight years old.
Structural Differences
Male brains are about 8% larger than female ones. Women have more gray matter and less white: the opposite is true for men. In women, the two hemispheres of the brain look alike. In men, they are asymmetrical. Women have more gray matter in their neocortex area (the "new" part of the cerebral cortex); men have more gray matter in the entorhinal cortex, one of the "older" areas of the brain. The massa intermedia of the thalamus are smaller or even missing in males. These structures are much larger in females.
As children develop, male or female hormones affect brain development and seem to determine the size and structure of different areas of the brain. The United States National Institute of Health is currently studying the brain development of 450 healthy children from birth to 18 years. So far, the researchers have found that the brains of children under age six develop very quickly, but the process levels off for children ages 10 to 12 years. During adolescence, brain development continues at a slow rate and does not complete until age 25 years or so.
In a study by researchers at Virginia Tech, Professor Harriet Hanlon and her associates found striking and consistent sexual differences between the brain development of 224 girls and 284 boys ages two months to 16 years. The girls matured more quickly in areas of the brain involving language and fine motor skills. While the girls were six years ahead of boys in those areas, the boys were four years ahead of the girls in areas of the brain that involve targeting and spatial memory. Two-year-old boys were much more likely to be able to build a bridge from blocks. However, three-year-old girls could understand facial expressions better than five-year-old boys.
When children reach adolescence, brain differences again are striking. In very young children, emotional activities take place in the subcortical area of the brain, specifically in the amygdala. The amygdala is not connected to the part of the brain that names activities – this is why very young children cannot express why they are feeling a certain way. However, seventeen-year-old girls are very adept at expressing and understanding emotions because their center of emotional thought had moved from the amygdala to the cerebral cortex. In boys, this center stays stuck in the amygdala, which is why they have trouble expressing and understanding emotions even in adolescence.
Functional Differences
Women's brains are not only different from men's, they also work differently.
The female brain is more decentralized. Women use a variety of parts of their brains when they do a single task. They do what researchers term "whole brain thinking." The female brain is more integrated with more complex connections between both hemispheres. Thought and emotion is more complex than in the male brain. Women can think logically and emotionally at the same time. For example, when a woman serves on a jury, she can understand the emotional reasons that drove a person to commit a crime and process these emotions along with the logic and consequences of the law.
Yale professor Dr. Sally Shaywitz has shown that men use the left side of their brains when they listen to someone speaking, whereas women use both sides. This means that women process the information they hear from human speech in a different way than men do.
Men navigate by using abstract concepts such as north and south or distances. Women navigate by talking about landmarks and things that can be seen or heard. For example, a man might give directions such as, "Go five miles northeast and turn west," whereas a woman might say, "Start at the Circle K with the large 7-Up sign." A study at York University concluded that the reason behind the two different strategies is that men use their left hippocampus regions when they navigate. However, women use the cerebral cortex. Both methods work, but they work differently.
Sexual Differences and Education
The new research on the differences between male and female brain structure and function has huge implications for educational theory. Girls learn differently than boys do because they think differently. This implies that educators should "teach to the differences."