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The human brain grew as a result of the extinction of large animals: new paper

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Re: The human brain grew as a result of the extinction of large animals: new paper

#51

Post by TeMPOraL »

statstutor wrote: post #37
karpierz wrote: post #14

This line of thinking falls into a common issue I have with evo-psych work. The paper proposes a mechanism that could select for intelligence, but doesn't provide evidence that the mechanism caused humans to evolve to be intelligent. It's the equivalent of the "Is-Ought" fallacy for empirical sciences.

I often find it "justifying human exceptionalism" presented as science. The unstated assumption is that humans are somehow better than chimpanzees (here, it is almost literally stated), and therefore that we must reverse engineer and fill in the gaps to justify this. It strikes me that I have no reason to believe the assumption, nor any way of reverse engineering the random process of natural selection. In my opinion…

> The unstated assumption is that humans are somehow better than chimpanzees

"Better" always has to carry the "at what?" part, explicitly or implicitly. There's no universal Better, thus humans aren't Better than chimpanzees - but humans are better than chimpanzees at quite a lot of things, including intelligence, learning, preserving knowledge across generations, use of tools...

> therefore that we must reverse engineer and fill in the gaps to justify this

There's nothing to justify here. We just are better - by far - than every other animal on this planet at the things that makes a species rule every other. This is an observable fact of reality. We had no contenders for this status as far as the recorded history goes. But it's interesting why this is the case. Why us, and not chimpanzees.

> any way of reverse engineering the random process of natural selection

Natural selection isn't completely random! If it were, there wouldn't be any complex life forms on Earth. Or, more strictly, for natural selection to be completely random, the universe would have to be a fully uniform blob of matter.

There's randomness involved in natural selection, but that randomness has a strong bias. That bias itself is the part that's interesting to understand / reverse engineer.

Re: The human brain grew as a result of the extinction of large animals: new paper

#52

Post by rightbyte »

karpierz wrote: post #14

This line of thinking falls into a common issue I have with evo-psych work. The paper proposes a mechanism that could select for intelligence, but doesn't provide evidence that the mechanism caused humans to evolve to be intelligent. It's the equivalent of the "Is-Ought" fallacy for empirical sciences.

How about the opposite. Smart humans could hunt dangerous animals. The causality is not obvoius ...

Re: The human brain grew as a result of the extinction of large animals: new paper

#53

Post by fearling »

rightbyte wrote: post #52
karpierz wrote: post #14

This line of thinking falls into a common issue I have with evo-psych work. The paper proposes a mechanism that could select for intelligence, but doesn't provide evidence that the mechanism caused humans to evolve to be intelligent. It's the equivalent of the "Is-Ought" fallacy for empirical sciences.

How about the opposite. Smart humans could hunt dangerous animals. The causality is not obvoius ...

This was my first thought as well.

Re: The human brain grew as a result of the extinction of large animals: new paper

#54

Post by _RPL5_ »

I find their hypothesis suspect.

> According to the researchers, the decrease in the size of game and the need to hunt small, swift animals forced humans to display cunning and boldness—an evolutionary process that demanded increased volume of the human brain.

There are plenty of predators that hunt fast small prey, but don't have advanced cognitive capacities. Cats, for example, are adapted to hunting rodents, but have pretty small brains.

> As humans moved into permanent settlements and became farmers, their brain size decreased to its current volume of 1300-1400cc. This happened because, with domesticated plants and animals that don't take flight, there was no more need for the allocation of outstanding cognitive abilities to the task of hunting.

There are active hunter-gatherer societies out there (or at least societies that lean heavily that way along the hunter-farmer axis). Do these societies have larger brains than everyone else? Seems like a simple way to test their hypothesis.

Re: The human brain grew as a result of the extinction of large animals: new paper

#55

Post by statstutor »

tryonenow wrote: post #45
statstutor wrote: post #37

Earlier quoted context omitted.

I often find it "justifying human exceptionalism" presented as science. The unstated assumption is that humans are somehow better than chimpanzees (here, it is almost literally stated), and therefore that we must reverse engineer and fill in the gaps to justify this. It strikes me that I have no reason to believe the assumption, nor any way of reverse engineering the random process of natural selection. In my opinion…

>I often find it "justifying human exceptionalism" presented as science. The unstated assumption is that humans are somehow better than chimpanzee You find it unscientific to observe that humans are exceptional for being the only known species with the ability to dominate and shape any environment, create, process, and communicate abstract thought, practice science, generate art, communicate across the planet instant…

> If that isn't scientifically provable exceptionalism, I don't know what is

My point is that it isn't scientific at all.

Any person can declare themselves exceptional - I have observed consistently that if a person has to declare they are exceptional themselves, it means they probably aren't.

I don't assume that general rule to be different on a species-level: if we (as the human race) feel a need to spend a lot of effort making claims to why we are exceptional, acting both as the judge and the jury, it leads me to suspect that we probably are not.

Re: The human brain grew as a result of the extinction of large animals: new paper

#57

Post by tashoecraft »

airhead969 wrote: post #8
tashoecraft wrote: post #3

Earlier quoted context omitted.

Interesting. Wonder if this conflicts with the idea that human brains grew as a result of eating more meat. That instead human brains grew due to evolutionary need of harder to catch meat sources.

As protohumans and humans invaded lands, they likely extincted megafauna and flora calorie and protein sources that were easiest to access. This then likely required more mental effort and creativity to solve food security problems with hunting and gardening.

It's interesting as it's a common argument that "meat caused us to have big brains, meat good", but that analysis might not be so clear cut. If this paper is right it may be more of the search for meat is what caused our brains to grow and less so meat protein.

Re: The human brain grew as a result of the extinction of large animals: new paper

#58

Post by vkou »

karpierz wrote: post #14

This line of thinking falls into a common issue I have with evo-psych work. The paper proposes a mechanism that could select for intelligence, but doesn't provide evidence that the mechanism caused humans to evolve to be intelligent. It's the equivalent of the "Is-Ought" fallacy for empirical sciences.

The immediate consequence of me reading evo-psych work, is that I conclude that pretty much all evo-psych work should be piled into a large bonfire, and burned.

This is the direct result of an obvious evolutionary psychological adaptation - being warm helps people survive, and fire is warm - therefore, if I were to do that, I would just be following an, ahem, evolutionary imperative.

Re: The human brain grew as a result of the extinction of large animals: new paper

#59

Post by cschwarm »

karpierz wrote: post #14

This line of thinking falls into a common issue I have with evo-psych work. The paper proposes a mechanism that could select for intelligence, but doesn't provide evidence that the mechanism caused humans to evolve to be intelligent. It's the equivalent of the "Is-Ought" fallacy for empirical sciences.

Interestingly, this isn't "evo-psych work", as anyone would see who'd knew how evolutionary psychology works.

In fact, the kind of argument used by the authors is more in line what human paleontology looks like.

Re: The human brain grew as a result of the extinction of large animals: new paper

#60

Post by statstutor »

TeMPOraL wrote: post #51
statstutor wrote: post #37

Earlier quoted context omitted.

I often find it "justifying human exceptionalism" presented as science. The unstated assumption is that humans are somehow better than chimpanzees (here, it is almost literally stated), and therefore that we must reverse engineer and fill in the gaps to justify this. It strikes me that I have no reason to believe the assumption, nor any way of reverse engineering the random process of natural selection. In my opinion…

> The unstated assumption is that humans are somehow better than chimpanzees "Better" always has to carry the "at what?" part, explicitly or implicitly. There's no universal Better, thus humans aren't Better than chimpanzees - but humans are better than chimpanzees at quite a lot of things, including intelligence, learning, preserving knowledge across generations, use of tools... > therefore that we must reverse engi…

I appreciate these points, which are well-considered.

> But it's interesting why this is the case. Why us, and not chimpanzees.

As you admit, we could ask about exceptional adaptations in other species, e.g. "why do birds rule the sky, and not other species?". This might be sometimes studied, but there is not nearly a comparable level of interest in that form of exceptionalism. I'd say there's so little interest, that we often fail to even observe such cases.

It strikes me that we are really just interested in ourselves. (I have no problem with that.)

I don't think we will learn very much as long as we start with the assumption we are primarily exceptional above all other species. I think it immediately leads to circular logic, where any and all differences become evidence supporting the assumption.

I accept what you say about natural selection having a bias. I remain doubtful that we are truthfully observing that bias over the noise of essential randomness. (Edit: on further consideration, I'd strengthen this and believe it is statistically impossible to distinguish evolutionary pressure from randomness, if you are considering N=1 runs of evolution).

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