Research about the brain has found subtle but significant biological differences between male and female brains. Among the findings:
- Male brains are six to ten percent bigger, on average, than female brains.
- Female brains have more synapses (connections) than male brains.
- Females have a bigger connecting area (the corpus callosum) between the two hemispheres of the brain. They tend to use both sides of the brain for a particular task more frequently than do males.
Differences begin before birth.
JoAnn Deak, Ph.D., an expert on brain research, reports that the differences in male and female brains start in the womb. “Many female brains have more neurons in certain areas than male brains, as a result of having more estrogen bathe them during fetal development. A hormonal/chemical wash (estrogen for girls, testosterone for boys) actually enhances certain parts of the brain and changes them structurally before birth. Therefore, each of us is born with different hard wiring.”
Girls’ brains develop at a different pace.
Girls and boys appear to have different developmental timelines, due in part to the differences in their brains. “For example,” Deak notes, “most girls are born with language processing neurons on both sides of the brain, but most males have them only on the right side.” As a result, girls often become earlier readers than boys and begin the writing process sooner. Many girls have less spatial awareness than boys but, at the same time, develop fine motor skills earlier than many boys. Most boys, however, tend to be more attracted to spatial tasks (such as playing with Legos) than most girls.
Most girls can (and will!) talk about emotion more easily than boys.
Most girls’ and boys’ brains are wired to process the connection between language and emotion differently. Because of this, according to Deak, many girls may have an easier time talking about their feelings than many boys. In addition, female brains tend to focus a bit better on details, so that girls can express their emotions at considerable length. Girls (particularly pre-pubescent ones) also have greater sensitivity to noise and tone of voice. As a result, some girls may hear yelling when there is only firmness in an adult’s voice, or take feedback on their work as negative criticism, even when it’s constructive.
Girls and boys react differently to stress.
Hormones shape how girls’ and boys’ brains react to fear and stress. Under stress, everybody releases hormones such as epinephrine or cortisol, which prepare the body for fight or flight. However, recent research shows that females also produce oxytocin, a hormone connected to childbirth that is thought to enhance connection and caring. From a species survival standpoint, this response may increase the probability that females will take care of offspring or band together when threatened. Deak terms this the “double whammy” that makes risk-taking harder. “This increases the likelihood that a threatened female will get out of the situation rather than fight. Boys, on other hand, get a surge of testosterone, which can modulate fear and promote aggression.” Deak encourages parents to help their girls take important risks and assert themselves in challenging situations.
Anatomy is not destiny.
The research does not claim that all girls’ (or boys’) brains work the same way, or that a girl’s behavior is predestined by brain chemistry. Catherine Steiner-Adair, Ed.D., co-author of Full of Ourselves: A Wellness Program to Advance Girl Power, Health and Leadership, notes also that the research does not fit all girls. “If 20 percent of girls do not fit this pattern, that’s one out of five, and that’s a pretty big percentage. We therefore shouldn’t make any assumptions about all girls’ behavior being the same.”
David Walsh, Ph.D., author of Smart Parenting, Smarter Kids, points out that while brain science tells us there are differences between boy and girl brains, it is important to note that no two brains are alike and that biology does not mean destiny. It is important not to lock kids into stereotyped ex