Last December, a major study was published by the
Proceedings of the National Academy of Sciences on sex differences in neural
connectivity. The authors of the study
used neuroimaging techniques to examine the brain of nearly 1000 participants,
roughly 50/50 male and female. The
participants ranged in age from 8-22.
The results of the study revealed that male brains showed greater
connectivity within each hemisphere
while female brains showed more connectivity across brain hemispheres. In
lay terms, the results indicate, according to the authors of the study, that
men would generally be better at activities, such as sports, due to greater
spatial awareness and coordination.
Further, women would generally be better at activities grounded in
socializing and memory. The authors go
on to suggest that the results denote a trajectory of brain functioning between
males and females, because the ages of participants ranged from childhood into
emerging adulthood. They used these
results to emphasize the structure of the brain as being inherently different
between sexes, which will be important to keep in mind while reading below.
The results of the study made their way into mainstream
media and began a firestorm of debate.
News and popular blogs began reporting the initial results declaring, in
essence, “Men are better at reading maps and women are the great multi-taskers
we always thought they were.” The
summary of the study continued to be diluted by news outlets from both sides of
the aisle, including the Guardian and the Wall Street Journal. Luckily, neuroscientist Cordelia Fine and
journalist Kat Stoeffel came to the rescue and laid down some real science for
us. Issues that confound the conclusions
of the study include:
·
The influence of brain size
·
The fact that the participants in the study were
a subset of a larger study that found “trivially small” sex differences in
psychological skills, including spatial processing and social cognition
·
The absence of consideration of gendered
experiences, such as personal hobbies
·
The absence of information on the origin of
these differences
·
The fact that the study did not actually test
for the activities it claimed men or women would be better at
·
The results were statistically significant but
are not supported by other neuroscience research actually measuring these
psychological abilities
At this point, I am reminded of what a professor once told
my class about the correlation between height and intelligence – even though
it’s significant, it is also not meaningful.
The aspect of this study I find the most disappointing is
how easy it is to poke holes in the methodology and conclusions. Any person with a rudimentary understanding
of gender socialization could easily negate these conclusions. We already know that children learn colors
and toys associated with gender in the first few years of life. Even an 8-year-old child has already been in
enrolled in soccer, ballet, plays ‘school’ or ‘house’ with friends, or reenacts
a superhero show at recess. They are not
the blank slate of sex differences assumed to be the case.
In addition, critical publications in recent years have
underscored the tendency of behavioral scientists and those using neuroimaging
techniques to select specific cases of data and use convoluted statistical
analyses to foster and overstate their conclusions. Full disclosure: I have not examined the
statistical analyses of the study in question.
However, this desire to manifest statistical significance for whatever
reason (I would speculate to get published) is noteworthy.
Upon discussion of these findings, my friend and colleague
responded to me that “science is amoral.”
Checkmate, right? I mean, the
speed of light is the same meters per second whether I’m turning on lights in a
hospital or in a prison. But, the
concept of science is a human construct, and we create the study, the
methodology, and report the results. We
have Institutional Review Boards, because even though there are queries we want
to entertain, we have decided as a field to take a moral high road and not
conduct experiments that cause harm to others.
So, how can we really find out if there are hard-wired sex
differences? At first, I thought, “Who
could we look at who has not been affected by gender socialization?” Newborns.
Newborns have been the
participants of experiments related to sex differences. For the most part, the jury is still out, but
the evidence thus far leans toward no differences aside from brain size. Further, the issues discussed above with
regard to statistical significance and publication muddle what we really
know. Studies finding no differences are
not “interesting” so we never find out about them.
Generally speaking, we do have some evidence of how the
environment changes the brain.
Specifically, interventions in psychotherapy alter intensity of activity
in certain regions of the brain. Also,
studies of individuals who meditate suggest that connections in the medial
prefrontal cortex change with increasing meditation. If these processes change intensity and
connectivity, then could repeatedly playing ‘teacher’ influence the structure
of the brain?
But, what about what we learned sex education? You know, with the onset of puberty, we
excrete certain hormones that serve as the catalyst for changes in and on our
bodies. However, testosterone, estrogen,
and progesterone are produced, provided there are no problems with hormone
production, in both sexes. Further, diet
and exercise also influence the levels of these hormones in the body. Thus, even though the foundations are laid
for sex differences, the expression of these differences is incredibly complex.
My hypothesis is that finding evidence for hard-wired,
unmalleable sex differences in the brain in the absence of gender socialization
is an untestable hypothesis in the current state of science. Now, I am not arguing that the consideration
of sex and gender differences is not a worthwhile cause to contemplate. However, there are so many within group
differences that get neglected when we present over-simplified research and
reinforce gender binaries. At this
point, my opinion on this matter is that with the state of neuroimaging
techniques and pervasive research on gender socialization, finding evidence for
gender differences in hard-wiring of the brain is like chasing a windmill.
Written by Teresa Young
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