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Sapiens - Part One: The Cognitive Revolution

#159: May - July 2018 (Non-Fiction)
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Sapiens - Part One: The Cognitive Revolution

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Sapiens: A Brief History of Humankind
Part One: The Cognitive Revolution


Please use this thread for discussing the above mentioned section of Sapiens. :chatsmilies_com_92:
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Re: Sapiens - Part One: The Cognitive Revolution

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Harari begins the book with a big picture history of the universe - familiar numbers but still so amazing to contemplate. It's always a challenging exercise for me to get my head around the expanse of time from the Big Bang 13.5 billion years ago to the formation of our planet 9 billion years later, the emergence of life 1 billion years later, the evolution of the genus Homo in Africa 2.5 million years ago and finally to modern humans 70,000 years ago.

It's interesting how so many of our species still views itself as set apart from the rest of the animal kingdom. After reminding us that our closest living relatives include chimpanzees, gorillas and orang-utans, Harari gives us this image: "Just 6 million years ago, a single female ape had two daughters. One became the ancestor of all chimpanzees, the other is our own grandmother."

He makes another important point about our very early ancestors: "These archaic humans loved, played, formed close friendships and competed for status and power – but so did chimpanzees, baboons and elephants. There was nothing special about humans.....The most important thing to know about prehistoric humans is that they were insignificant animals with no more impact on their environment than gorillas, fireflies or jellyfish." (my emphasis)

Sapiens is only the latest variety of our species. The Neanderthals are familiar to most of us. But, I was surprised to learn about a number of other human species that evolved. Homo erectus, 'Upright Man' survived for close to 2 million years, making them, by far, the most durable human species ever.

Another species evolved on the island of Java, in Indonesia, Homo soloensis, ‘Man from the Solo Valley’.
On the small island of Flores, another Indonesian island, archaic humans underwent a process of dwarfing. Humans likely reached Flores when the sea level was low, and the island was easily accessible from the mainland. When the seas rose again, many were trapped on the island. The theory is that big people who need a lot of food died first. Smaller people survived much better. Over the generations, the people of Flores became dwarves. This unique species, known by scientists as Homo floresiensis, reached a maximum height of only 3.5 feet and weighed no more than fifty-five pounds.

I find this next example of an extinct human species particularly interesting. In 2010, when scientists were excavating the Denisova Cave in Siberia, they discovered a fossilised finger bone. Genetic analysis proved that the finger belonged to a previously unknown human species, which was named Homo denisova. When one considers how unlikely this discovery was we must conclude that there are likely many lost relatives of ours waiting to be discovered in other locations.
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Re: Sapiens - Part One: The Cognitive Revolution

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I was struck by the same line about the two daughters in the first chapter. It reminded me of the Dawkins thought experiment about your ancestors gradually turning into a fish.

I never really thought about humans being a "middling" species for those 2 million years, but makes sense if they didn't have the tools to master their environment like humans do now. I was also fascinated by the insight that for other species, "millions of years of dominion have filled them with self-confidence... Having so recently been one of the underdogs of the savannah we are full of fears and anxieties over our position..."

And the puzzle of why the big brains, when it didn't have obvious evolutionary advantage until much later -- although I suppose in hindsight you could say that it proved effective. I remember reading an explanation -- I assume he talks more about this later, don't remember if it was him or someone else -- about how the big brains were mostly needed for navigating the social environment. I'm a little unclear on when the social environment became significantly more complex than for other animals.
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Re: Sapiens - Part One: The Cognitive Revolution

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Dexter wrote:And the puzzle of why the big brains, when it didn't have obvious evolutionary advantage until much later -- although I suppose in hindsight you could say that it proved effective. I remember reading an explanation -- I assume he talks more about this later, don't remember if it was him or someone else -- about how the big brains were mostly needed for navigating the social environment. I'm a little unclear on when the social environment became significantly more complex than for other animals.
As I understand that dramatic jump in our evolutionary history. The human species had been around for over 2 million years without much change. Several species of humans came and went over the period. Homo sapiens evolved around 150,000 years ago in East Africa with little change until somewhere around 70,000 years ago. We're told that something major changed in the brains of sapiens at that time which resulted in a period of expansion and extermination of every other human species. Homo sapiens were now at the top of the food chain.

Harari's description of the sapiens sudden jump in dominance centers around one unique capacity of our species - the ability to create and tell stories about ourselves. Earlier humans, relying on personal ties were limited to a group size of about 150. This ability to create unifying stories about ourselves was what enabled sapiens to create communities and nations of millions.This ability further allowed sapiens to accumulate knowledge so they could make changes in their behavior without waiting for those changes to be encoded in their DNA as is the case with the rest of the animal kingdom.
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Re: Sapiens - Part One: The Cognitive Revolution

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I’m just getting to the next section, he is able to clarify big issues quite well, of course at the possible risk of oversimplifying. I liked this quote:

“Any large-scale human cooperation- whether a modern state, a medieval church, an ancient city or an archaic tribe - is rooted in common myths that exist in people’s collective imagination.”

This applies to so many other things than just religion.
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Re: Sapiens - Part One: The Cognitive Revolution

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LevV wrote: Sapiens is only the latest variety of our species. The Neanderthals are familiar to most of us. But, I was surprised to learn about a number of other human species that evolved. Homo erectus, 'Upright Man' survived for close to 2 million years, making them, by far, the most durable human species ever. . . .
I'm really looking forward to reading about the changing picture of early man. Fascinating stuff.

I have been on the road this week. I did stop by Barnes & Noble, but the hardcover was $35, and I wanted the paperback version, which was being released this past Tuesday. I ended up ordering from Amazon and it will be waiting when I get home.
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Re: Sapiens - Part One: The Cognitive Revolution

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LevV wrote:On the small island of Flores, another Indonesian island, archaic humans underwent a process of dwarfing. Humans likely reached Flores when the sea level was low, and the island was easily accessible from the mainland. When the seas rose again, many were trapped on the island. The theory is that big people who need a lot of food died first. Smaller people survived much better. Over the generations, the people of Flores became dwarves. This unique species, known by scientists as Homo floresiensis, reached a maximum height of only 3.5 feet and weighed no more than fifty-five pounds.
This is great, I had no idea we have a Dwarf cousin species. Maybe they'll find the remains of elves in the Amazon someday.

The problem is that many people don't consider this knowledge. They consider it all a part of the myth of science. Fanciful tales of grandfather monkeys.
In the beginning the Universe was created. This has made a lot of people very angry and has been widely regarded as a bad move.” - Douglas Adams
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Re: Sapiens - Part One: The Cognitive Revolution

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Interbane wrote:
LevV wrote:On the small island of Flores, another Indonesian island, archaic humans underwent a process of dwarfing. Humans likely reached Flores when the sea level was low, and the island was easily accessible from the mainland. When the seas rose again, many were trapped on the island. The theory is that big people who need a lot of food died first. Smaller people survived much better. Over the generations, the people of Flores became dwarves. This unique species, known by scientists as Homo floresiensis, reached a maximum height of only 3.5 feet and weighed no more than fifty-five pounds.
This is great, I had no idea we have a Dwarf cousin species. Maybe they'll find the remains of elves in the Amazon someday.
This event is an example of the sort of evidence with which Stephen Jay Gould challenged the standard model of evolution. In his popular writings is an account of rapid adaptive change driven by selection but not by mutation. In Gould's typical account, mutation is a background process more useful for genetic clocks than for speciation. If you think about it in this case it makes some sense.

The idea that random errors in DNA could generate such a dramatic change in the size range of a bunch of hominids is not really credible. Take a typical population of humans today and ask how many of them are shorter than four feet tall, with or without dwarfism. The percentage has to be tiny. So now suppose we apply selection pressure, as has been done with dogs, and ask how many generations it will take to get a population you can breed chihuahuas from. The answer is not that many generations. Evidently, Gould concludes, there is an ongoing process of generating random variation in each generation, at least along dimensions of variation for which selection pressure might matter, be it speed, arm length, visual acuity, or you name it. Of course we knew this. Not every child is an average of father's (family's) height with mother's (family's) height, for example. Every generation kicks out examples who are outside the range for which they already have the genetic material.

Of course that does mean that there are "copying errors", but these are a feature, not a bug. Gould suggested in one essay that it might be the number of copies of a particular codon that varies systematically for a particular trait, and that these codon counts contain a "variation generator." Call it mutation if you want, but it is probably not the highly dangerous kind of random DNA copying error that we usually think of when we talk about "mutation."

There is also some question whether floresiensis is really a different species. Just as chihuahuas can interbreed with Saint Bernards, and either of them with wolves, so we have some evidence homo sapiens interbred with Neanderthals. Okay, those are different species, but still close enough that one could challenge the distinction. Maybe all those varieties we find finger bones for are really just subspecies.
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Re: Sapiens - Part One: The Cognitive Revolution

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Dexter wrote:And the puzzle of why the big brains, when it didn't have obvious evolutionary advantage until much later -- although I suppose in hindsight you could say that it proved effective. I remember reading an explanation -- I assume he talks more about this later, don't remember if it was him or someone else -- about how the big brains were mostly needed for navigating the social environment. I'm a little unclear on when the social environment became significantly more complex than for other animals.
I am hoping we get into this subject more in Sapiens. Hariri ((oops, Harari)) has given some indication already of the series of interlocking changes in biology that accompanied one another and, presumably, the emergence of cultural practices which amplified the changes and made them adaptive.

Brain size is one obvious one that he dwells on, and speech, which makes much of culture possible, is another crucial one. We probably all more or less have heard the list: bipedalism, opposable thumbs, long gestation (I liked Harari's (ed.) note as to the toll that takes on women's health), loss of body hair, (seems like there was some crucial adaptation making possible the cooling needed for our extravagant brains, like maybe more sweat glands), and the cultural creations which fed off these changes and made them effective: fire, tool-making, hunting as an organized group process, lying to each other, and all the complex arrangements by which we manage long-term mating to raise children, leading in turn to further biological developments such as hidden (and non-compulsive) estrus.

That interplay of culture with biological changes is the big story, and I am eager to hear more about it. As an economist, I would guess that the interlocking changes exerted enough restraint on each other that the net result was a slow exponential growth of both population and brain size, with advancement in each permitting a slight acceleration in the others. (Not exactly punctuated equilibrium, except that the time scale for speciation is usually many, many generations so it is not as different as "slow exponential growth" sounds.)
Last edited by Harry Marks on Mon May 21, 2018 2:03 am, edited 1 time in total.
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Re: Sapiens - Part One: The Cognitive Revolution

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I've only read the first chapter in the section. I know what he's getting at with the "insignificant animal" label, but I would rather that he choose a more neutral descriptor. Is one species really more significant than another? Harari assumes that large-scale effects on the environment, or top-ranking in the food chain, confers significance. He's comparing our recent achievement of dominance with our much longer status as a species having to struggle to stay afloat, back when the playing field was level. He suggests that our original niche was that of marrow-eaters, coming in after the predators and scavengers have had their fill. So no doubt our beginnings were humble, and they lasted for an extremely long time. From the same retrospective view, though, we could say that homo was a very significant animal for the new qualities of thinking, communication, and technology that emerged with it. These traits weren't amped up enough yet for homo to take charge, plus it took eons in those days for culture to develop.

I also wonder whether it's true that homo was just scraping by 150,000 years ago, as Harari says. A population of a million doesn't seems that shabby when you take into account that human bands would need large territories. Different species of homo becoming extinct doesn't necessarily indicate that the niche of this genus lacked opportunity or was under particular stress.

I was interested in Harari's explanation for the increasing social abilities of homo. Walking upright narrowed women's hips, making giving birth more difficult even as brain and head sizes were increasing. Women who gave birth earlier died less often, so birthing very undeveloped babies became the norm. These human babies required more attention than the mother was able to provide, requiring a social network of helpers. I don't know if this alone can explain our social natures, but it does have the advantage of avoiding the controversy over group selection that purports to explain the same thing.

What did you all think of Harari's idea about the origin of our fears and anxieties? I can't see that our relatively sudden vault to the top of the food chain caused us not to be able to develop the confidence and aplomb that Harari says other apex predators have. Nice try, but our anxieties must have something to do with being too smart for our own good.
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