6 ms·

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

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 were factors at different points in human evolution. Here's a quick attempt at some broad categories, which each have multiple hypotheses within them: * Because intelligence had advantages for individual selection (e.g. mimetic recall hypothesis) * Because intelligence had advantages for group selection * Because intelligence had advantages for sexual selection (spandrel hypotheses often start here) * Because adapting to rapidly varying ecological conditions required so many adaptations that we crossed some kind of barrier and "fell into" intelligence * Because intelligence helped with foraging/hunting (exclusive of sociality)

gyomu 1y ago
Didn't a lot of other great apes evolve intelligence similar to ours, but we more or less drove them all to extinction?
- AlotOfReading 1y ago
  The jury is still out on exactly how intelligent other hominins were (and the extent of our involvement in their extinction). Regardless, the term human can apply to all of genus Homo and that's the sense that discussions of "human intelligence" typically use.
  - nylonstrung 1y ago
    The burial sites of Homo Naledi suggest they had developed burial rituals and primitive art which would mean non-Sapiens hominids were likely smarter than previously believed
    - david-gpu 1y ago
      The subject of Homo Naledi is very controversial. Take it with a grain of salt.
- Gravityloss 1y ago
  it's interesting to think that since humans got established, becoming too intelligent became a disadvantage? Like there's a glass ceiling.
  - zmmmmm 1y ago
    I like that theory although it is depressingly grim ... the top dog species will inherently see any alternative intelligence as a threat and eradicate it. Would definitely make one pause for thought about the wisdom of creating an AGI ...
    - dsign 1y ago
      Came here to say this, but you did it for me :-) . I truly believe there's a more than 50% chance the vast history of hominids ends this century.
  - Ekaros 1y ago
    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.
    - 8bitsrule 1y ago
      > Human brains are expensive in terms of energy I dunno ... 10 bits/second ain't so lavish...
      - dotancohen 1y ago
        Perhaps, but 1/3 of your blood supply is expensive.
  - energy123 1y ago
    Since the invention of contraception, intelligence seems maladaptive, although we may have already reached technological escape velocity so it's not clear to me that it'll matter.
- shakna 1y ago
  Less than more. Most of the early hominids crossbred. For as much violence as there was, there was also a lot of sex. Less extinction, and more evolution.
strogonoff 1y ago
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-primate-evolution-gave-humans-the-voice-apes-lack https://www.theguardian.com/science/2022/aug/11/how-quirk-of... [1] https://www.bbc.com/future/article/20240517-the-human-brain-has-been-shrinking-and-no-one-quite-knows-why 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-became-worlds-best-fungus-farmers-180962871/ https://www.smithsonianmag.com/science-nature/how-ants-becam...
- AlotOfReading 1y ago
  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.
  - strogonoff 1y ago
    It is not my idea per se, of course… I only gathered (well, it seems sort of obvious) that, given the overwhelmingly social nature of human intelligence, communication with high information throughput is likely the key differentiator between HS and other apes; the rest was ~1 minute of googling. As to “side effect”, given better communication and consequently cooperation and potential for more complex collectives lead to persistent survival of the species in the environment, they seem like a pretty straightforward evolutionary advantage that would be expected to be naturally selected for in the first place. If anything, chances are in long term the great larynx update is the real side effect, it just happened to be a trait enabling all the above evolutionary advantages.
ekianjo 1y ago
How about if we were the only apes to not fear fire as much and discovered that we get much more nutrients by cooking stuff?
- AlotOfReading 1y ago
  Stone tools predate even the oldest suggestions of intentional fire use by at least a million years, so the cooking hypothesis isn't particularly compelling. Elsewhere in this thread I've also discussed how it's not really an explanation either.
  - Theodores 1y ago
    The cooking hypothesis is not well known, however, from what I understand, this was when we went from having big guts and average brains to small guts and big brains. The fossil record of primates is far from complete, but roughly speaking, we have been eating cooked food for a million years. The stone tools that predate this by a few million years reinforce the cooked food hypothesis in this 'chicken or egg' situation.
andrewflnr 1y ago
I hadn't heard the term "spandrel" before, especially not in this context. Makes sense, though. https://en.wikipedia.org/wiki/Spandrel_(biology) https://en.wikipedia.org/wiki/Spandrel_(biology)
- rirze 1y ago
  I personally dislike the definitions here-- traits and genetic changes are, by default, unattributed to external pressures. They don't "arise" from the environment, rather the environment selects for traits through survival/reproduction, if applicable. That means, if a trait is unaffected by the environment, then there's no attribution of why it developed; this is the default state. I feel often in biology, there's a mindset of figuring out why features developed and that's great for pushing the field but it runs into a limit. Not every trait developed from a environmental pressure.
  - andrewflnr 1y ago
    Technically yes, kind of, but if a feature is truly unaffected by the environment, then there's no particular reason it would get fixed, and you have to make the rather shaky assumption that it became widespread purely by chance. Most features have some cost, and the simplest explanation for that feature being widespread is that it has some counteracting benefit that leads to it being selected for. That's a reasonable first hypothesis, to say the least, which means the "spandrel" hypothesis makes sense as the less common special case.
    - rirze 1y ago
      > Most features have some cost I don't agree and that's totally fine-- we have millions of gene edits from parent to child and not every change is environment-selected. Certain features can be dominant by the mechanics of genes, not due to selective pressure. Blood types are an example of this-- they aren't major environmental pressures for why one blood type is more common than others, it mostly comes down to population mechanics. My belief is that "spandrel" features are less selected for studies because they have a harder burden to prove; there exists no external reason they exist and this must be verified through proof by contradiction. Its a high bar to prove.
bigbrained124 1y ago
The only logical pathway is that some genetic mutation or plant-based hallucination allowed for lack of animalistic fear/true context generation within the brain. Understanding that bear/tiger/snake/etc won’t kill you in certain circumstances, means you can expend exponentially less calories and focus on building tools etc. It allows for rapid growth across the species in many areas.
KurSix 1y ago
This highlights just how little we really know, even with decades of fossil, genetic, and behavioral data. What's always struck me is how intelligence might not have been a linear "goal," but more like a byproduct of other traits that just happened to snowball...
anal_reactor 1y ago
I'm a huge fan of the hypothesis that: 1. Survival is easier in groups 2. In order to survive in groups, we need to communicate 3. We communicate using language 4. Language is directly linked with intelligence See how computers started displaying intelligence when we taught them our language
- ChrisGreenHeur 1y ago
  all of this applies to monkeys
  - anal_reactor 1y ago
    Yes but we were first

gyomu 1y ago

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

AlotOfReading 1y ago
The jury is still out on exactly how intelligent other hominins were (and the extent of our involvement in their extinction). Regardless, the term human can apply to all of genus Homo and that's the sense that discussions of "human intelligence" typically use.
- nylonstrung 1y ago
  The burial sites of Homo Naledi suggest they had developed burial rituals and primitive art which would mean non-Sapiens hominids were likely smarter than previously believed
  - david-gpu 1y ago
    The subject of Homo Naledi is very controversial. Take it with a grain of salt.
Gravityloss 1y ago
it's interesting to think that since humans got established, becoming too intelligent became a disadvantage? Like there's a glass ceiling.
- zmmmmm 1y ago
  I like that theory although it is depressingly grim ... the top dog species will inherently see any alternative intelligence as a threat and eradicate it. Would definitely make one pause for thought about the wisdom of creating an AGI ...
  - dsign 1y ago
    Came here to say this, but you did it for me :-) . I truly believe there's a more than 50% chance the vast history of hominids ends this century.
- Ekaros 1y ago
  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.
  - 8bitsrule 1y ago
    > Human brains are expensive in terms of energy I dunno ... 10 bits/second ain't so lavish...
    - dotancohen 1y ago
      Perhaps, but 1/3 of your blood supply is expensive.
- energy123 1y ago
  Since the invention of contraception, intelligence seems maladaptive, although we may have already reached technological escape velocity so it's not clear to me that it'll matter.
shakna 1y ago
Less than more. Most of the early hominids crossbred. For as much violence as there was, there was also a lot of sex. Less extinction, and more evolution.

strogonoff 1y ago

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-primate-evolution-gave-humans-the-voice-apes-lack https://www.theguardian.com/science/2022/aug/11/how-quirk-of... [1] https://www.bbc.com/future/article/20240517-the-human-brain-has-been-shrinking-and-no-one-quite-knows-why 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-became-worlds-best-fungus-farmers-180962871/ https://www.smithsonianmag.com/science-nature/how-ants-becam...

AlotOfReading 1y ago
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.
- strogonoff 1y ago
  It is not my idea per se, of course… I only gathered (well, it seems sort of obvious) that, given the overwhelmingly social nature of human intelligence, communication with high information throughput is likely the key differentiator between HS and other apes; the rest was ~1 minute of googling. As to “side effect”, given better communication and consequently cooperation and potential for more complex collectives lead to persistent survival of the species in the environment, they seem like a pretty straightforward evolutionary advantage that would be expected to be naturally selected for in the first place. If anything, chances are in long term the great larynx update is the real side effect, it just happened to be a trait enabling all the above evolutionary advantages.

ekianjo 1y ago

How about if we were the only apes to not fear fire as much and discovered that we get much more nutrients by cooking stuff?

AlotOfReading 1y ago
Stone tools predate even the oldest suggestions of intentional fire use by at least a million years, so the cooking hypothesis isn't particularly compelling. Elsewhere in this thread I've also discussed how it's not really an explanation either.
- Theodores 1y ago
  The cooking hypothesis is not well known, however, from what I understand, this was when we went from having big guts and average brains to small guts and big brains. The fossil record of primates is far from complete, but roughly speaking, we have been eating cooked food for a million years. The stone tools that predate this by a few million years reinforce the cooked food hypothesis in this 'chicken or egg' situation.

andrewflnr 1y ago

I hadn't heard the term "spandrel" before, especially not in this context. Makes sense, though. https://en.wikipedia.org/wiki/Spandrel_(biology) https://en.wikipedia.org/wiki/Spandrel_(biology)

rirze 1y ago
I personally dislike the definitions here-- traits and genetic changes are, by default, unattributed to external pressures. They don't "arise" from the environment, rather the environment selects for traits through survival/reproduction, if applicable. That means, if a trait is unaffected by the environment, then there's no attribution of why it developed; this is the default state. I feel often in biology, there's a mindset of figuring out why features developed and that's great for pushing the field but it runs into a limit. Not every trait developed from a environmental pressure.
- andrewflnr 1y ago
  Technically yes, kind of, but if a feature is truly unaffected by the environment, then there's no particular reason it would get fixed, and you have to make the rather shaky assumption that it became widespread purely by chance. Most features have some cost, and the simplest explanation for that feature being widespread is that it has some counteracting benefit that leads to it being selected for. That's a reasonable first hypothesis, to say the least, which means the "spandrel" hypothesis makes sense as the less common special case.
  - rirze 1y ago
    > Most features have some cost I don't agree and that's totally fine-- we have millions of gene edits from parent to child and not every change is environment-selected. Certain features can be dominant by the mechanics of genes, not due to selective pressure. Blood types are an example of this-- they aren't major environmental pressures for why one blood type is more common than others, it mostly comes down to population mechanics. My belief is that "spandrel" features are less selected for studies because they have a harder burden to prove; there exists no external reason they exist and this must be verified through proof by contradiction. Its a high bar to prove.

bigbrained124 1y ago

The only logical pathway is that some genetic mutation or plant-based hallucination allowed for lack of animalistic fear/true context generation within the brain. Understanding that bear/tiger/snake/etc won’t kill you in certain circumstances, means you can expend exponentially less calories and focus on building tools etc. It allows for rapid growth across the species in many areas.

KurSix 1y ago

This highlights just how little we really know, even with decades of fossil, genetic, and behavioral data. What's always struck me is how intelligence might not have been a linear "goal," but more like a byproduct of other traits that just happened to snowball...

anal_reactor 1y ago

I'm a huge fan of the hypothesis that: 1. Survival is easier in groups 2. In order to survive in groups, we need to communicate 3. We communicate using language 4. Language is directly linked with intelligence See how computers started displaying intelligence when we taught them our language

ChrisGreenHeur 1y ago
all of this applies to monkeys
- anal_reactor 1y ago
  Yes but we were first