MORE ABOUT GENDER DIFFERENCES
Research sheds light on the female brain
By ROSEMARY J. STAUBER
In the January/February edition of SAN ANTONIO WOMAN, I followed up on a 2003 article on gender differences — a topic too large to address in a single column.
In the most recent article I cited two new books, both titled The Female Brain. The first was written by Cynthia Darlington, a British author, and was published in 2002 in London and New York by Taylor and Francis. The other is by Louann Brizendine, M.D., and was published In 2006 by Morgan Road Books. The new research is facilitated by modern technology, which allows scientists to examine live brains in action. I find it fascinating.
Continuing that topic in this issue, I will examine the role of hormones in the two genders and further discuss how our brains function differently. First, Brizendine includes a chart in her book (on pages xviii and xix of the introduction) that shows the different stages of hormone activity in the lives of women.
Here is an adaptation of the chart, including only the basics of it for space reasons.
| Hormone changes | Females have, males don’t | Female specific brain changes | Reality Change/focus | |
|---|---|---|---|---|
| Fetal | No testosterone to hamper brain growth/development | Brain cells XX- more genes, faster growth | Communication, gut feelings, emotional memory and anger suppression- unabated by testosterone | More brain circuits and able to use both sides of brain |
| Girlhood | Massive estrogen secretion from 6 mos to 24 mos, then turned off | High estrogen up to 2 years old |
Verbal/ emotional circuits are enhanced |
Connection, with girls |
| Puberty | Estrogen, progesterone & testosterone increase & cycle monthly |
More estrogen, less testosterone. Brains develop 2 years sooner than boys. | Increased sensitivity & growth of stress, verbal, emotion, and sex circuits | Sexual attractiveness, desperate love interests, avoidance of parents |
| Sexual Maturity, single Woman | Estrogen, progesterone & testosterone change every day of the month |
Focus on relationships, finding a mate, choosing career compatible with raising a family | Earlier maturation of decision-making and emotional control centers | Finding a mate, love, career development |
| Pregnancy | Huge increases in progesterone and estrogen | Focus on nesting, providing for family, less on career/competition | Stress circuits suppressed; brain calmed by progesterone; brain shrinks; hormones from fetus and placenta take over brain & body. | Own physical well-being/ coping with fatigue, nausea, and hunger, protecting the fetus. |
| Breast feeding | Oxytocin*, prolactin | Focus on baby | Stress circuits suppressed. Sex and emotion circuits hijacked by infant care | Fatigue, sore nipples, breast milk production, one day at a time |
| Child rearing | Oxytocin*; cycling estrogen, progesterone and testosterone | Less interest in sex, more worry about kids | Increased function of stress, worry, and emotional bonding circuits | Well-being, development, education, safety of kids; coping with increased stress at work |
| Perimenopause | Erratically cycling estrogen, progesterone, and testosterone | Fluctuating interest in sex, erratic sleep, more fatigue, worry, moods, hot flashes, irritability | Decreasing sensitivity to estrogen in certain brain circuits | Surviving day to day and coping with physical and emotional ups and downs. |
| Menopause | Low estrogen, no progesterone | Last precipitous brain change caused by hormones | Circuits fueled by estrogen, oxytocin*, and progesterone decline | Staying healthy, improving well-being and embracing new challenges |
| Postmenopause | Low, steady estrogen and testosterone; lower oxytocin* | Calmness | Circuits less reactive to stress, less emotional | Doing what you want to do; less interest in taking care of others. |
*Oxytocin is a "feel-good" brain chemical that facilitates bonding with the mate and with the children.
Research on gender differences in the brain is also under way at the Brain Behavior Center of the University of Pennsylvania's Department of Psychiatry by neuroscientists Drs. Ruben and Raquel Gur. From the Today show Web site, http://www.msnbc.msn.com/id/16187129/ I learned that the researchers use an MRI scanner to monitor how the brains of women and men work as they are answering emotional, verbal and spatial questions.
"Estrogen and progesterone are likely to be important factors when we talk about biological differences, but it is likely to go even beyond that," says Dr. Raquel Gur.
On that Web site you can be a part of the research by taking their online test. One interesting outcome of that research is the information that while women can easily read facial expressions and determine what the emotions behind them are, men usually have to work hard to come to those conclusions. (Various parts of the man's brain "light up" showing use, while only one or two do so with the woman.)
That is why women frequently think they are demonstrating their unhappi¬ness to a man, and he just doesn't get it. He doesn't read the subtle nuances of her facial expressions. If she wants a response, she needs to tell him what she's feeling.
So it seems we women are programmed to connect with a mate at some time, produce children and care for them. By menopause, we are free, so to speak. In the September/October 2005 issue of SAN ANTONIO WOMAN, I wrote about a "crossover" effect in which women of middle age are moving out and becoming more involved in the outside world, while men become more interested in nesting. The chart above explains the woman's side of that effect.
Dogs that had not been treated in this way would immediately jump over the barrier to the shock-less cage. Wanting to teach the experimental dogs that they were not helpless, the researchers lowered the barriers, attached leashes to their collars, applied the shock, then quickly dragged the dogs across into the other cage. It took between 200 and 250 trials to teach them that they could escape. (Normal dogs will learn a new trick in 6 to 10 trials.)
And what about the male brain and male hormones? Are they as "programmed" as the women? I checked the Internet using "testosterone" as a key word and found only the following from Wikipedia, in a June 2006 article titled Testosterone:
"Adult testosterone effects are more clearly demonstrable in males than in females, but are likely important to both sexes. Some of these effects may decline as testosterone levels decline in the later decades of adult life.
And Professor Thomas Perls has done research leading to a book, Living to 100. An excerpt was published in healthandage.com. He wrote that while boys and girls start life in the womb with the boys ahead 115 to 100, at birth the advantage is down to 104 to 100, and by age 25, women outnumber men. Boys' deaths outnumber girls' deaths at all stages of life. Between 15 and 24 the male propensity for taking risks, dubbed "testosterone toxicity" by some, takes a higher proportion of male lives.
There is a danger that women will be stereotyped, and as in days gone by, it will be decided that they can't function in the work place and government (until menopause?) because of the higher emotionality and sensitivity. It would make just as much sense to say, however, that men can't function in the workplace and the government because of their propensity for higher emotionality (anger is an emotion, after all) and risk-taking behavior.
Michael Gurian, Men's Health Center, in an article titled A Friendly Look at the Male Brain sums it up for me:
"Fortunately, the new sciences are now showing us the unlimited potential of human nature. These sciences are not taking us back into old roles. In fact, quite the opposite. They liberate us to discover who and what a person really is. They free us to make love convincingly, to love compassionately, to honor the human soul, to notice human courage, to make marriages work again, and to care for others as human beings yearn to do."
I add, "and to function in the world of work and government."
Rosemary J. Stauber, Ph.D., is a clinical psychologist in San Antonio and founding director of the Bexar County Women’s Center.