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In other words, the evidence that the “Female Brain” is less smart than the male brain after puberty starts to crumble whenever you put pressure on it.
IQ tests might tease out some sort of significant difference, but the results only sort of correlate with what other research has shown about girls’ and boys’ cognitive aptitudes.
the differences in tested ability are much smaller than the differences in who gets the jobs.
But the language test results are fairly robust: girl children do better at language tests than boy children, and those differences are still present after puberty.
But when we listen to a conversation between a man and a woman, we usually think the woman talks more than she actually does—even if she’s reading a script with the same number of words as she’d spoken opposite another female.
So, when we say “girls are better at language,” what we really mean is that girls score better in verbal tests, depending on what sort of verbal test is being given.
Women are generally better at reading and writing.
Men make up only 20 percent of the people who buy and read novels. The numbers improve for history and other nonfiction,
For reasons that are still unclear, boys are two to three times more likely to be dyslexic than girls.
It’s a bit of a Venn diagram of differences and overlaps, but the overall rate of occurrence of mental illness is probably about equal in men and women.
Women commit suicide roughly three times less often than men.
men are more likely to wind up in the ER from severe traumatic brain injuries, but women are more likely to recover from them.
Most of the damage from traumatic brain injuries is caused not by external force but by what nearby cells do in response to the damaged cells.
Male brains seem to suffer more extensive inflammation and lesions around injury sites than females’ do.
And this might be because progesterone and the estrogens—the classic female sex hormones—have a protective effect on brain tissue, dampening that inflammatory response.
you dose both dishes of neurons with things known to stress out or even kill them, XY neurons die faster and more often.[*19] The main reason for this, as far as scientists can tell, is that male XY cells have more difficulty dealing with oxidative damage.
And in the end, that might be why modern human brains are so functionally similar between the sexes: The evolution of the hominin line wasn’t just about surviving in one place. It was about building a body and a set of behaviors that could work for lots of places.
And then, over a span of about 1.5 million years, the brains of a wide range of hominins started massively expanding.
For many of today’s scientists, the reason our Eves got so much brainier through this stretch lies in climate change.
This rule holds for all Mammalia, actually: historically, being omnivorous is the best way to survive.
Tiny creatures called forams live on the seafloor, as they’ve done for hundreds of millions of years, long before there were mammals or dinosaurs. When they die, they leave a useful layer of microscopic skeletons. In those skeletons, traces of stable oxygen are woven into the matrix of the fossilized bone.
About six to seven million years ago—when our Eves split from chimps—climate change sped up.
But some species, instead of adapting to specific environments, evolve a set of traits and behaviors useful in many different environments. This is called “variability” selection.
Or even better than being omnivorous, what if you found a variety of ways to make just about anything edible?
That way, no matter where you went, you could make the local food work for you.
Cooking does that. Pounding tough plants with ...
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Human brains are structurally a bit different from our ape cousins’. For instance, we have a massively expanded prefrontal cortex.
But here’s the funny thing: when human beings are born, overall, our brain size is roughly equal to a newborn chimp’s. We’re a lot fatter than chimp babies, to be sure, and we only get fatter from there, but our brains aren’t so very different.
what happened to our ancient ape brain when hominin evolution beefed up that frontal cortex and gave it a superlong childhood.
somewhere deep in the hominin line—somewhere between Lucy and Homo sapiens—the hominin genome started messing with three things inside the womb and in early childhood: skull, brain, and fat.
Human fetuses build up their fat stores in the third trimester and continue building body fat throughout infancy and early childhood.
Newborns drink 16 percent of their body weight in milk every day for the first six months of their life.
After our brains reach 80 percent of their adult size at age two, we take a much longer time to build the remaining 20 percent.
Our brains aren’t done internally organizing until somewhere in our early to mid-twenties.
First, there’s hardware. As the brain grows bigger in those first two years of life, neuron stem cells seem to migrate from one portion of the brain to another, building out the frontal cortex massively and laying down highways between this “higher order” brain region and the areas that control movement and sensory information.
The human brain reaches peak synaptic density—that’s when the most neurons are the most wired to other neurons—when we’re around two.
Then the brain starts violently pruning itself back, like an overzealous master gardener.
Toddlers, for example, can sit at a table and point at something they want. Chimpanzees, however, seem to feel the need to get up, clamber over the table, gesture wildly, and continually look toward the thing they want and back toward their caretakers.
That means they’re good—probably innately good—at quickly building shared social understanding.
kids learn how to point in part because they have to, since unlike chimps they can’t get about on their own until they’re at least seven to twelve months old.
In other words, maybe the reason human brains have so few sex differences in their overall functionality is that the need for that adaptability overrides many of the built-in sex differences left over from our mammalian heritage.
Our Eves’ children needed to learn how to solve problems in their environment—not just specific problems, but any problems. Social interdependence is a very
pregnant and breast-feeding women just so happen to have brains that are doing very similar things to what human brains do at other major transitions in our body’s life cycle: they violently rearrange themselves.
Some researchers suspected it was mostly fluid loss (brains don’t have noticeably fewer neurons in late pregnancy, but lower general volume),
It’s kind of a mess inside a pregnant mother’s third-trimester brain, and likewise in the early months after giving birth.
From what we can see in hunter-gatherer communities today, the beginning of ovulation happens in the late teens, which neatly aligns with the tail end of our long period of human juvenile social learning and brain development.
for most of human history, human girls arrived at menarche when our bodies had enough gluteofemoral fat and bone growth (and a suitably low amount of daily stress) that becoming pregnant might not be too harmful, which also usefully aligned with a point in human-typical brain development that would allow for maternal brain changes to not overlap with earlier puberty.
That her body is a thing that’s seen, and that men are the ones who are doing the seeing.
DNA. In his memoir, one of Watson’s central complaints was that “Rosy” never prettied herself for the lab: he noted that she never wore lipstick to lighten her features and that “her dresses showed all the imagination of English blue-stocking adolescents.”
the sympathetic-adrenal-medullary axis (SAM). We mostly use SAM in classic fight-or-flight moments,
