Have you ever had trouble understanding how the opposite sex thinks? Do they sometimes seem like they are from another planet? If so, then you will have no difficulty believing that male and female brains can vary from each other. After all, men and women behave differently, so it is reasonable to assume that their brains are at least partially responsible for those behavioral differences. Studies have indeed shown that there are anatomical and functional distinctions between the two. There is still no definitive answer as to how much of these differences are caused by male versus female brains and how much is caused by society pushing women toward verbal, people-oriented careers and men toward quantitative careers like engineering, math or computers. Although we can only theorize about society’s role, let’s take a look at what we do know about male versus female brains- how they depart from each other in looks and in what ways they function differently.
Brain Structure
Size:
Almost all studies to date have shown that a boy’s brain, at birth, is approximately 12-20% larger than a girl’s brain. Their head circumference is 2% larger. However, if body weight is accounted for there seems to be little difference. In adults, the average male brain is 11-12% larger than the female brain and the head remains about 2% larger in circumference. Even when accounting for height and weight differences, men have slightly larger brains.
Harvard researchers in 2001 discovered that specific areas of the brain were different sizes in males and females. They found that parts of the frontal lobe (involved in problem solving and decision making) and the limbic system (regulating emotions) were larger in women. The study also found that the parietal cortex (space perception) and the amygdala (sexual and social behavior) were larger in men. These differences appear to balance out the overall size discrepancy.
Furthermore, men have about 6.5 times more gray matter but women have more than 9.5 times more white matter. Men seem to think with their gray matter which consists of active neurons, while women think with their white matter which is made up of the connections between the neurons. The neurons are more densely crowded in women’s brains; more connections and more tightly packed neurons might allow the female brain to think faster than a male brain.
In imaging studies, researchers have found not only denser female brains and larger male brains, but also that the sexes access different regions of the brain to do the same activity. For example, in a study that utilized sounding out different words as the task, men tended to use one small area of the left hemisphere to complete the task while women utilized both hemispheres. Interestingly, the sexes performed equally well suggesting that there are multiple ways for the brain to come up with the same result. Despite all the discrepancies, average IQ scores are the same for both males and females.
Corpus Callosum:
The bridge of nerve tissue that connects the right and left hemispheres is called the corpus callosum. Many studies have found the corpus callosum larger or more developed in women, but there are some studies that reported no significant discrepancies. Israeli researchers, using ultrasound, found that by 26 weeks into a pregnancy the female fetuses had thicker measurements in the corpus callosum than in male fetuses.
Hypothalamus:
The hypothalamus, on the other hand, has well-documented distinctions between men and women. There are two areas of the hypothalamus (the preoptic area and the suprachiasmatic nucleus) that have demonstrated clear differences.
Preoptic Area:
In males, the preoptic area (involved in mating behavior) is greater in volume, has twice as many cells and is 2.2 times larger than in females.
Suprachiasmatic Nucleus:
This area is involved in circadian rhythms and reproduction cycles. Here the difference is in shape: in males it is shaped like a sphere but in females it is more elongated.
Brain Function
Academic/language skills:
Male and female brains have their own areas of expertise. Males do better with spatial tasks (mentally rotating or manipulating an object), navigating routes and mathematical reasoning. Women shine on tests that measure word recall, verbal memory and remembering where objects are located.
The inferior-parietal lobule, which controls numerical brain function, is larger in males. In contrast, the parietal region is thicker in females which makes it harder to do spatial tasks such as mentally rotating objects. Women often report more difficulty with spatial tasks, both on tests as well as in real life.
Generally, boys outshine girls in brain processing of math and geometry; those areas of the male brain mature 4 years earlier than in the female brain. Researchers concluded that when it comes to math, the brain of a 12 year old girl resembles that of an 8 year old boy. But before the female readers take offence, the study also noted that areas of the brain responsible for processing language and fine motor skills mature 6 years earlier in girls compared to boys. Women often excel at language-based tasks for two reasons. As previously mentioned, they have two brain areas that are involved with language processing that are larger, and females use both hemispheres to process language while males rely on just the left.
Emotions:
Women are faster and more accurate at identifying emotions according to neurologist Ruben Gur (University of Pennsylvania). He and his colleagues discovered that the female brain is larger in areas that control aggression and anger, suggesting that women may be better than men at controlling their emotions. Perhaps due to their larger limbic system, women are more in touch with their feelings and better at expressing their emotions. Women are alleged to have better communication skills and emotional intelligence than men; they are more apt to talk out solutions to problems. Many men have difficulty picking up on emotional cues unless they are clearly verbalized. These basic differences in emotional responding can cause communication between the sexes to be difficult at times and lead to misunderstandings.
Brain function disorders:
Males tend to be more left brain dominant and, thus, more susceptible to dyslexia and other language based disabilities. They are also more disposed toward autism, ADHD and Tourette’s syndrome. Women are more prone to mood disorders like anxiety, depression or bipolar disorder.
The recent studies and facts mentioned above may lead us to believe that male and female brains have little in common. That’s not true; men and women have significantly more similarities than they do differences. Also note that there are many individual exceptions to any gender stereotype or generalizations, but exceptions don’t invalidate these generalizations. For example, there are plenty of women with excellent spatial skills and lots of men with superior writing skills. Not all men will have a strong male brain and not all women will have a strong female brain. But, in general, far more men are likely to have the male brain and far more women are likely to have the female brain. Although disparities in male and female brains can explain some behavior, many other differences in cognitive behavior (like memory) are related to individual differences between people, rather than due to whether or not they are a man or a woman.
Resources
http://brainfitnessforlife.com/brain-anatomy-and-imaging/9-differences-between-the-male-and-female-brain/
http://health.howstuffworks.com/human-body/systems/nervous-system/men-women-different-brains1.htm
http://www.webmd.com/balance/features/how-male-female-brains-differ
http://faculty.washington.edu/chudler/heshe.html