Nature (founded 1869), proceeding from the completely materialist assumption that the human mind is simply what the brain does, offers a look recently at some of the more remarkable aspects of the human brain. The article features amazing graphics but three information items stand out:

Researchers can now snoop on what happens inside millions of brain cells by cataloguing the genes, RNA and proteins they produce. And by studying brain tissue, scientists are learning key lessons about how the organ develops and functions.

One is that the differences between human brain cells and those of other species are often subtle. Another is that the human brain develops slowly compared with other animals. But how these features give rise to our cognitive skills is still a mystery — although researchers have plenty of promising leads.

Kerri Smith and Nik Spencer, “What’s so special about the human brain?” October 31, 2024

Do they? Can these features, as described, really explain what made Aristotle. (384– 322 BC) or Einstein (1879–1955) different? Even from other human beings? Because that’s the big question: What is the source of new ideas?

More from Nature:

Brain size is tightly correlated with body size in most animals. But humans break the mould. Our brains are much larger than expected given our body size.

Researchers often use a ratio called the encephalization quotient (EQ) to get an idea of how much larger or smaller an animal’s brain is compared with what would be expected given its body size. The EQ is 1.0 if the brain to body mass ratio meets expectations.

Here are their brains scaled according to their EQ, with the actual brain sizes represented by dotted lines. The mouse brain is half as big as expected for its body size. The human brain is more than seven times the expected size. “What’s so special?

Well then, maybe brain size is not as important as it is cracked up to be? We still aren’t anywhere near a purely natural explanation for why humans think about stuff like the universe and chimpanzees think about eating fruit and monkeys…

Apparently, it is not the brain as such

Nature continues:

Take these two comparable regions of the human and mouse cortex, which both process auditory information. The mouse area contains a higher proportion of excitatory neurons, which propagate signals, relative to inhibitory neurons, which dampen activity. The human region had a much greater proportion of non-neuronal cells, such as astrocytes, oligodendrocytes and microglia. These cells support neurons and also help to prune and refine their connections during development. The ratio of these cells to neurons was five times that of mice. The upshot of the differences still isn’t clear, but the atlases provide a way to study these cells and the genes they express, to better understand their function. “What’s so special?

If a life form’s life-deciding issue is escaping a cat, we needn’t be surprised to learn that excitatory neurons rule. But we can’t really go from that to understanding what makes humans different.

And we also learn,

Although some changes to genes and cells undoubtedly make us who we are, it’s too early to leap to any conclusions, says Alex Pollen, a geneticist who studies human brain evolution at the University of California San Francisco. Some changes could just be side effects of other adaptations — for example, an increase in certain types of neuron so that brain regions could still communicate when the brain expanded.

There are downsides, too, to our special abilities. Sherwood says that humans undergo more drastic changes than other primates, such as a shrinkage of the cortex, owing to ageing — in part because we live so much longer. But even the oldest great ape brains don’t seem to change as much as human brains do with age, he says. And some conditions that seem specific to humans could be the price we pay for complexity, says Lancaster. “Even a small defect could have more dramatic consequences,” she says.

“What’s so special?

But somehow, it doesn’t seem like we have learned more about human nature. Human nature isn’t entirely in our brains. But Nature might not be the right place to talk about it.