Gender-Based Brain Differences
We know that there are gender-based differences in the bodies
of humans. But what about in our brains? What are the cognitive
differences that can be considered innate? Here is what some
of the research shows.
BBC Science, working with researchers in North America and
the United Kingdom, created a research project on psychological
sex differences in conjunction with Secrets of the Sexes,
a documentary program. During three months (February-May 2005)
they surveyed people using the internet, with over 250,000 people
from around the world responding.
The results, which were reported in the April 2009 issue of
the Archives of Sexual Behavior (Volume 36, No 2), included
* Not surprisingly, it was confirmed that all mental abilities
decline with age. However, men's mental abilities decline more
on average than women's, and this appears to be true regardless
of sexual orientation.
* Across all cultures, men scored higher on tests of mental
rotation and the ability to judge line angles. Women scored higher
on word fluency and tests of object location memory.
* Visual-spatial abilities of gay men were more likely to
be similar to womens abilities. The visual-spatial abilities
of lesbian women were more likely to be similar to men's.
Other studies have shown differences that are innate. In a
on LiveScience.com, Diane Halpern, who has studied cognitive
gender differences for over 25 years and currently works at Claremont
McKenna College in California as a professor of psychology, was
quoted as saying, "We do socialize our boys and girls differently,
but the contribution of biology is not zero."
The differences are sometimes exaggerated. It is commonly
assumed that boys are better than girls at math, and that this
difference is innate. But Halpern says that in cultures that
are more gender-equal the higher scores and greater apparent
math abilities for males is not evident.
On the other hand, when both boys and girls are given essentially
equal encouragement (and access) to education, some differences
are actually accentuated. Girls become better at reading, according
to Halpern, and with visual-spatial tasks the scores for boys
surpass those of girls even more.
Halpern notes that regardless of gender differences in their
brains, cognitive development is impaired (on average) by poverty.
Research at the University of Iowa, reported on in a Scientific
American article, shows that one particular part of the ventral
prefrontal cortex is proportionally larger in women. The ventral
prefrontal cortex is active when we make interpersonal judgments,
and used for what is referred to as "social cognition."
The part that is larger (by about 10% proportionally) in women
is the straight gyrus or SG. This was not only a larger part
of the brains of the women tested (30 women were compared to
30 men), but in men and women a larger SG correlated with higher
scores on tests of interpersonal awareness.
One clear gender difference is that men's brains are larger
than women's. They are about 10% on average. But this does not
offer any specific advantage to men versus women, because the
more relevant measure is brain size in relation to body size.
Elephants, after all, are not considered more intelligent than
humans, even though their brains are a little over ten pounds,
compared to about three pounds for humans. An elephant's brain
is about .1% of its weight, while a human's is about 2%, making
it proportionally 20 times larger. Since the brain is used to
direct all of the various systems in an animal's body, in general
a larger body requires more brainpower, presumably leaving less
for cognitive tasks.
Note: Perhaps the most relevant measure is brain
size proportional to the size of the body systems (frame size,
length of blood vessels, and so on), not weight. After all, there
is little evidence that a person's brain function shifts focus
from cognitive tasks to more body regulation with weight gain.
In other words we do not become less intelligent because fat
These are interesting findings perhaps, but are they useful
in some way? When dealing with individuals and their characteristics,
the generalizations that come from science are not usually relevant.
For example, it is reasonable to conclude that men are, on average,
physically larger and stronger than woman, but that says nothing
about a specific person. Plenty of specific women are larger
and stronger than many specific men. The usefulness of gender-based
brain research might be in how we design education. Compensating
for the differences with specific curriculums is a possibility.
But there is a valid question as to whether attempting to equalize
specific abilities or brain functions is a worthy or necessary