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Study of 1M-year-old skull points to earlier origins of modern humans

theguardian.com

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Re: Study of 1M-year-old skull points to earlier origins of modern humans

#41

I'm curious why humans evolved intelligence and chimpanzees, gorillas, orangutans did not.

We don't know. All of the great apes are incredibly intelligent in comparison to most other animals. The basic roots of our intelligence are probably a common feature to the whole family, but there's no consensus on why it's so advanced in humans. Any paleoanthropologist can rattle off about half a dozen possible explanations, but we honestly don't have enough evidence to really distinguish if, when, and how these we…

Considering human intelligence is very social, I wonder if bias to focus on individual humans leads us to a wrong way of understanding why it arose…

One of my pet theories is that it may be related to vocal cord development[0], where losing certain physiology that allows apes to be louder allowed humans to be more specific, if quieter, with enhanced pitch control and stability offering higher information density communication. This unlocks more complex societal interactions and detailed shared maps. (In Iain McGilchrist’s terms, it let the Emissary—the part of the brain shown to specialize in classification and pattern recognition, the requisite building blocks for efficient communication—to take priority.)

This is an example highlighting how it is not about individual humans “becoming smarter”, evolving larger brains, etc., but rather about humans becoming capable of working together in more sophisticated ways. In fact, human brain shrunk in the last few thousands of years, in concert with growing size of our societies and labour specialization[1], which in turn in no small part is helped by communication density offered by our vocal cords. Really, humans in this way are closer ants[2], where being part of human community is the defining part of our nature.

[0] https://www.theguardian.com/science/2022/aug/11/how-quirk-of...

[1] https://www.bbc.com/future/article/20240517-the-human-brain-...

[2] Ants that farm and have stronger division of labour have smaller brains: https://www.smithsonianmag.com/science-nature/how-ants-becam...

Re: Study of 1M-year-old skull points to earlier origins of modern humans

#42
post #17

I'm curious why humans evolved intelligence and chimpanzees, gorillas, orangutans did not.

chimpanzees, gorillas, orangutans evolved intelligence too. They are smarter than most other critters in the jungle. Just all not as much as the lineage that leads to humans. It's actually quite difficult to define human intelligence. Every time we think we find something unique by humans eventually some animal turns up that can do it too. It may be all just a question of degree and how it's used.

From what I've heard, language is unambiguously unique to humans, if you consider grammar an integral part of languages. You can teach chimpanzees hand signs, but they could never make the leap to stringing them together under a coherent rule: something like the difference between "Mom give me cookies" vs "I give mom cookies."

(I'm no expert, so take that with a grain of salt.)

Re: Study of 1M-year-old skull points to earlier origins of modern humans

#43
post #11

I'm curious why humans evolved intelligence and chimpanzees, gorillas, orangutans did not.

"Why humans evolved intelligence but orangutans did not". There's a different way to think about this that is closer to how evolution actually works and will make the answer clear. Our common ancestor (common to orangutans and humans) did evolve intelligence (concurrently with harnessing fire, clothing etc.). Not all of them, but some of them. And they broke off from the group. We now call them humans.

Intelligence must surely be a cluster of evolved changes, let's say A-Z. Each of those letters must have appeared, and been advantageous on their own (or they wouldn't have persisted).

So why didn't chimps get some of them?

For example, chimps have hands, but do not exhibit anywhere near the dexterity and agility of human hands.

Re: Study of 1M-year-old skull points to earlier origins of modern humans

#44
post #11

Earlier quoted context omitted.

"Why humans evolved intelligence but orangutans did not". There's a different way to think about this that is closer to how evolution actually works and will make the answer clear. Our common ancestor (common to orangutans and humans) did evolve intelligence (concurrently with harnessing fire, clothing etc.). Not all of them, but some of them. And they broke off from the group. We now call them humans.

Intelligence must surely be a cluster of evolved changes, let's say A-Z. Each of those letters must have appeared, and been advantageous on their own (or they wouldn't have persisted). So why didn't chimps get some of them? For example, chimps have hands, but do not exhibit anywhere near the dexterity and agility of human hands.

It’s more like A appeared and there was a split off. Then B appeared and another split off from the A group and so on until you get to modern day Z.

Re: Study of 1M-year-old skull points to earlier origins of modern humans

#45

I'm curious why humans evolved intelligence and chimpanzees, gorillas, orangutans did not.

That question is analogous to asking why did some fish grow legs and become mammals. The answer is mutations sometimes specific members of a group will gain a mutation that will overtime cause that group to split off away from the ancestor group. It’s all a matter of chance evolution doesn’t have a direction.

Multiple lines of mammals have independently evolved back into being marine life. Whales, seals and manatees do not have a common ancestor, for example.

Re: Study of 1M-year-old skull points to earlier origins of modern humans

#46
post #42
post #17

Earlier quoted context omitted.

chimpanzees, gorillas, orangutans evolved intelligence too. They are smarter than most other critters in the jungle. Just all not as much as the lineage that leads to humans. It's actually quite difficult to define human intelligence. Every time we think we find something unique by humans eventually some animal turns up that can do it too. It may be all just a question of degree and how it's used.

From what I've heard, language is unambiguously unique to humans, if you consider grammar an integral part of languages. You can teach chimpanzees hand signs, but they could never make the leap to stringing them together under a coherent rule: something like the difference between "Mom give me cookies" vs "I give mom cookies." (I'm no expert, so take that with a grain of salt.)

Cetacean communication obeys Zipf's law: https://pmc.ncbi.nlm.nih.gov/articles/PMC11797547/

As does house finches: https://royalsocietypublishing.org/doi/full/10.1098/rspb.202...

Sperm whale codas exhibit contextual and combinatorial structure: https://www.nature.com/articles/s41467-024-47221-8

Ants have developed symbolic language: https://pmc.ncbi.nlm.nih.gov/articles/PMC10093743/

Everywhere we look close enough, we find life doing smart things.

Re: Study of 1M-year-old skull points to earlier origins of modern humans

#47
post #23

Earlier quoted context omitted.

Didn't a lot of other great apes evolve intelligence similar to ours, but we more or less drove them all to extinction?

it's interesting to think that since humans got established, becoming too intelligent became a disadvantage? Like there's a glass ceiling.

I think it might be just competition. Human brains are expensive in terms of energy expenditure. So at certain population scales having less energy to expend might be comparative advantage.

And same really goes for other niches we do not even occupy. You need to get something out of those expensive to keep brains.

Re: Study of 1M-year-old skull points to earlier origins of modern humans

#48

Earlier quoted context omitted.

We don't know. All of the great apes are incredibly intelligent in comparison to most other animals. The basic roots of our intelligence are probably a common feature to the whole family, but there's no consensus on why it's so advanced in humans. Any paleoanthropologist can rattle off about half a dozen possible explanations, but we honestly don't have enough evidence to really distinguish if, when, and how these we…

Considering human intelligence is very social, I wonder if bias to focus on individual humans leads us to a wrong way of understanding why it arose… One of my pet theories is that it may be related to vocal cord development[0], where losing certain physiology that allows apes to be louder allowed humans to be more specific , if quieter, with enhanced pitch control and stability offering higher information density com…

Depending on which factors you weigh most heavily, sociality theories usually fit into either individual or group selection categories. They're sort of the default consensus, but not one that's firm.

Your idea would be what's called a spandrel hypothesis, basically that language (or culture etc) is a side effect of other adaptive traits.

Re: Study of 1M-year-old skull points to earlier origins of modern humans

#49

I'm curious why humans evolved intelligence and chimpanzees, gorillas, orangutans did not.

All apes are intelligent. Studies have shown that their causal reasoning is almost on par with humans. What they seem to lack is language for communicating sophisticated concepts and persisting them across generations.

Re: Study of 1M-year-old skull points to earlier origins of modern humans

#50
post #11

I'm curious why humans evolved intelligence and chimpanzees, gorillas, orangutans did not.

"Why humans evolved intelligence but orangutans did not". There's a different way to think about this that is closer to how evolution actually works and will make the answer clear. Our common ancestor (common to orangutans and humans) did evolve intelligence (concurrently with harnessing fire, clothing etc.). Not all of them, but some of them. And they broke off from the group. We now call them humans.

I always believed that it was the group that had first mastered fire. Cooking food fundamentally changed human energy budgets. And keeping a fire meant that the group would congregate and form a larger social group, which would then lead to greater communication.

This of course changes the question as to why only/mainly homo erectus developed the capability.

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