Are Men's Brains Bigger?

girls running shoes

Girl's Sneakers

Smaller brains may be more efficient. Ounce for ounce, women get more brain bang for the buck, possibly because of the greater degree of connectivity between cells.

By: Marianne J. Legato, FACP and Laura Tucker

True or False: Men’s brains are bigger.
True. Whenever I lecture on this subject, nothing gets a more outraged response than this simple biological truth: Men’s brains are bigger than those of women and weigh 10 percent more.

But size isn’t everything. Women have more gray matter in certain parts of their brains and more intricate and extensive communications between brain cells than men, particularly in the frontal cortex. This is the area involved in judgment and decision making: the “executive center” of the brain. Some scientists think that this relatively more intricate system of neuronal interconnections explains why women’s brains have a higher rate of blood flow. In fact, smaller brains may be more efficient. Ounce for ounce, women get more brain bang for the buck, possibly because of the greater degree of connectivity between cells.

And while it is true that male fetuses have more brain cells than female ones do, this may be the reason boys have more developmental defects than girls; it may require more energy to keep these larger brains in tip-top shape. It takes a lot of energy to drive a brain, especially a baby’s brain, which has twice the number of working connections between cells as an adult’s does. Boys, with their bigger brains, have significantly lower heart rates and lower body temperatures than girls; just when they need the energy to support their bigger brains, they fall behind! A higher number of boys have developmental disorders that become apparent in early childhood, such as mental retardation, expressive and receptive language disorders, stuttering, and autism; the energy deficit may explain why.

True or False: Women are better at multitasking, while men are better when concentrating on a single task from beginning to completion.
True. Ruben Gur, PhD, and Raquel Gur, MD, PhD, at the University of Pennsylvania in Philadelphia, measured blood flow and activity in men’s and women’s brains, and they found repeatedly that women use more parts of their brains when given a wide variety of verbal and spatial tasks. They believe that this may contribute to women’s ability to focus on a number of different things at one time.

A new study has raised an important question: Women may be better at multitasking, but is multitasking really the most efficient way to work? Newer research shows that switching back and forth from one task to another takes precious seconds of reevaluation, and those seconds add up. As the researchers point out, in the best-case scenario, this makes you only slightly less efficient — but in the case of someone talking on a cell phone and driving, that fraction of a second may make the difference between life and death.

The conclusion I personally have come to is this: Multitasking is certainly helpful when you don’t have any options, when your assistant is out sick or when you’re trying to put dinner on the table while at the same time making sure your children are entertained and safe. But I find that when I need to concentrate on writing, it’s helpful for me to turn off my phone and my e-mail program, with its constant “new mail” alerts, so that I can better and more purely concentrate on the task at hand.

True or False: The effects of our sex hormones (such as estrogen and testosterone) are restricted to the reproductive system.
There are two interesting things about hormones. The first is how many hormones play a role in sexing us — not just the sex hormones, as you might think, but others, like the ones we release when we’re under stress.

The second is how many systems these hormones affect. Yes, estrogen is responsible for menstrual periods, but did you know that it also has a profound effect on the way women learn, think, and remember? For instance, estrogen may be one of the keys to the earlier questions about the differences between schizophrenia in men and women. Here’s a more pedestrian example: I tell patients with young girls to keep an eye on their daughters’ sneakers. The hormonal changes that announce puberty and bring on a girl’s first menstrual period will cause a sudden surge in her growth and a leap in her shoe size as well.

All of the hormones in the body have far-reaching effects, which is why it’s so important to take note when differing levels of them are found in men and women.

About the Authors:
Marianne J. Legato, FACP, is an internationally known academic physician, author, and lecturer. She is a professor of clinical medicine at Columbia University, where she founded and heads the Partnership for Gender-Specific Medicine. One of the world’s foremost experts on gender medicine and winner of many awards for her work, she is the author of The Female Heart, What Women Need to Know, andEve’s Rib. She recently edited the widely acclaimed academic textbook, Principles of Gender-Specific Medicine.

Laura Tucker is the coauthor of several health and medical books. She lives in Brooklyn, New York, with her husband and daughter.

Copyright © 2005 Marianne J. Legato, MD, FACP and Laura Tucker

Reprinted from: Why Men Never Remember and Women Never Forget by Marianne J. Legato, MD, FACP and Laura Tucker © 2005 Rodale Inc. Permission granted by Rodale, Inc., Emmaus, PA 18098. Available wherever books are sold or directly from the publisher by calling (800) 848-4735 or visit their website at

Photo: Daisy Mary