New Research Shows Male and Female Brains Hardly Differ

Dec 1, 2015

In the mid-19th century, researchers claimed they could tell the sex of an individual just by looking at their disembodied brain. But a new study finds that human brains do not fit neatly into “male” and “female” categories. Indeed, all of our brains seem to share a patchwork of forms; some that are more common in males, others that are more common in females, and some that are common to both. The findings could change how scientists study the brain and even how society defines gender.

“Nobody has had a way of quantifying this before,” says Lise Eliot, a neuroscientist at Chicago Medical School in Illinois who was not involved in the study. “Everything they’ve done here is new.”

As soon as scientists could image the brain, they began hunting for sex differences. Some modest disparities have been reported: On average, for example, men tend to have a larger amygdala, a region associated with emotion. Such differences are small and highly influenced by the environment, yet they have still been used to paint a binary picture of the human brain, “even when the data reveal much more overlap than difference between males and females,” Eliot says.

So in the new study, researchers led by Daphna Joel, a behavioral neuroscientist at Tel Aviv University in Israel, tried to be as comprehensive as possible. Using existing sets of MRI brain images, they measured the volume of gray matter (the dark, knobby tissue that contains the core of nerve cells) and white matter (the bundles of nerve fibers that transmit signals around the nervous system) in the brains of more than 1400 individuals. They also studied data from diffusion tensor imaging, which shows how tracts of white matter extend throughout the brain, connecting different regions.

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8 comments on “New Research Shows Male and Female Brains Hardly Differ

  • Really?

    How do they explain that 90% to 10% incarceration rate of males to females if only 8% of brains are “fully male.”

    Just one example, Now that we think we know that male and female brains overlap so well we should see changes all the way from parity in the military to women jack hammering sludge off the inside of oil storage tanks.

    New Research Shows Male and Female Brains Hardly Differ

    I won’t hold my breath until this plays out socially. I’ll need to look at that study more closely for sure.

    between 23% and 53% of brains contained a mix of regions that fell on the male-end and female-end of the spectrum. Very few of the brains—between 0% and 8%—contained all male or all female

    This part needs careful study. Please spare me the social constructionist blather here. As we should all know the greatest difference between men and women is there reproductive strategy. Two different ways to get to the same goal.

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  • The data is the data and if this is what it says, then I will follow the data. I was certainly within the camp that said that male and female brains had differences. I have argued in this forum that in relation to in-utereo hormonal dysfunction resulting in homosexual behaviour. If I am wrong, then I need to change.

    When reading the full article however, I was disturbed at the long bow being drawn by the researchers stretching to the implications of their research. They extrapolated these results to then get into social science as to what society should and shouldn’t do. For example.

    For another, she says, the extreme variability of human brains undermines the justifications for single-sex education based on innate differences between males and females, and perhaps even our definitions of gender as a social category.

    As a person married to a teacher, a daughter who is a teacher and who socialises with a cohort of teachers, there is academic research that indicates that at certain ages, and for certain subjects, separate male and female classes produce better results.

    My common sense tells me that males and females overlap. Two large bell curves that overlay, but don’t quite match. My commonsense tells me that there are differences between men and women, with the definition of “differences” to be read in its widest context.

    The skeptic in me must follow the evidence, but I have reservations.

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  • As we should all know the greatest difference between men and women is there reproductive strategy.

    You can say that again!

    It can only be stated in general terms of course, but I think this difference is manifested in the way the two genders approach sex itself, for which there are very sound evolutionary reasons of course.

    For instance, the different times it takes for arousal to occur; with men almost instantaneously, with women much slower; post-coitally however, the time scales are reversed.

    There are quite a few other differences as well but this is not the place to pursue them; for that, I recommend Simone de Beauvoir’s, Le Deuxieme Sexe.

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