Innate Differences Between the Sexes: Fact, Not Fantasy (Part 2)
By Lisa J. Lehr
We're different from a very early age.
An observer of a mixed-gender group of children of any age will see pretty standard gender-specific behavior across cultures, starting with the hospital nursery. Newborn girls are smaller and lighter, but healthier and developmentally ahead of newborn boys. Baby girls maintain more eye contact, while baby boys are more active and irritable.
Girls talk better at an earlier age. Boys, once having learned to walk, roam more. At age two, children prefer sex-typed toys (although they do not yet label them as such). By age three, boys have more muscle mass; girls have more fatty tissue. Also by this age, boys are able to throw a ball farther and more accurately, and build taller, more unstable structures.
On the playground, girls are more likely to congregate and welcome others to their activity, while boys are more apt to run around individually, and any newcomers to a "boys game must prove their worth before joining. Girls express emotion through words (including gossip) and use persuasion and negotiation to resolve conflict; boys show emotion through action (including hitting), and tend to use threats and physical means to solve problems. Boys social interaction occurs in large groups away from adult supervision; for girls, the opposite is true.
What studies of the brain have taught us.
Differences can be observed much earlier than preschool, even earlier than in the hospital nursery. A couple of decades worth of neurobiological research fully support the anecdotal evidence. With the advent of MRI and PET scans, we can study the brain, even in utero.
Obvious differences in brain structure explain the differences in the way members of the two sexes think. In both, the two hemispheres of the brain are connected by bundles of nerve fibers. As baby boys develop in utero, testosterone is produced. It then binds to brain tissue, doing significant damage to the connective nerve fibers. By the middle of gestation, the concentration of testosterone in the brain is comparable to that of a young man. The brain is permanently transformed.
The male brain shows more hemispheric asymmetry; the language area of the brain is larger in females. In an ultrasound exam at no later than 26 weeks of gestation, we can distinguish between male and female brains.
Because the female brain's connective nerve fibers remain intact, females use both hemispheres for processing phonetic language and problem solving, while males use only one. Males are better at gross-motor movements and are usually better and faster at arithmetic and math.
Now we understand why men seem to have trouble putting their feelings into words. The fact is, they can't, because the left brain controls speech, and the right, emotions. In men, these two parts are not connected. Also, feelings occur in a more primitive part of the brain than does speech. This changes during childhood; the brain's "feeling activity moves to a higher part of brain during adolescence, but only for girls. Grown men can no more put their feelings into words than can young children of either sex.
As for the parallel parking, the male brain has a significantly larger inferior parietal lobule, the part that is responsible for spatial awareness. It's that straightforward. By the way, this part was especially large in Albert Einstein's brain, and is in other physicists and mathematicians as well.
So, whatever kind of environment we choose to create for our children, the fact is, the environment is acting upon different kinds of brains.
Please continue to Part 3
About The Author
Lisa J. Lehr is a freelance writer with a specialty in business and marketing communications. She holds a biology degree and has worked in a variety of fields, including the pharmaceutical industry and teaching, and has a particular interest in health matters. She is also a graduate of American Writers and Artists Institute (AWAI), America's leading course on copywriting.
This article ©Lisa J. Lehr 2006.