Exceptional intelligence in the Holocene: why?

[Infinity Blade]

There seem to be quite a handful of multiple different animal clades today that have independently evolved exceptional cognitive abilities. The way I understand it, those in the uppermost echelon of animal intelligence include:

- Primates (especially monkeys and within them, apes)
- Elephants
- Odontocetes
- Corvids
- Parrots
- Coleoids (cuttlefish, squids, octopi)

So that's six independent occurrences of exceptional intelligence. All of which are alive right here, right now. And I wonder...why? What is it about the Holocene (or rather, the conditions immediately preceding it) that drove quite a handful of animal clades evolving a more or less similar level of exceptional intelligence?

And is it possible that similar environmental conditions have existed further back in the past and prompted the evolution of exceptionally smart animals millions of years before today (even though we don't seem to have any evidence of exceptional intelligence back then, especially during the Mesozoic or Paleozoic, and for a portion of the Cenozoic)?

[creature386]

I recall a post by Ursus arctos (it was in the "Could Gorgosaurus survive in North America today?" thread on the Carnivora archive) where he argued that there has been an average brain size increase in certain clades over time.
A lot of the clades you listed have been around well before the Holocene and most of them are mammals and birds, groups that are both relatively young (compared to some others) and dynamic.
Unfortunately, I can't access the archive for obvious reasons, so you'll have to search for his post yourself.
Actually, you won't, I can just link the thread:
www.tapatalk.com/groups/carnivora/could-gorgosaurus-survive-in-north-america-today-t14318-s10.html

[Infinity Blade]

Hmm, Ursus arctos' post seems to be more about relative brain size and how much of an indicator of success it is in a foreign environment than brain size increasing with time, assuming you're talking about his mega-post in that thread (although, he might be implying the latter).

I know a lot of the clades I listed were around well before the Holocene, but, assuming you do take the changes in encephalization quotient in these clades as any indicator of cognitive capacity (at least in these clades; I tend to not think of EQ as a reliable indicator of cognitive ability universally, but when limited to specific clades, I can buy it), then at least some weren't always up to the cognitive extent they are at now.

Regarding Ursus arcots' post, though: honestly, the crux of the point I want to make is the question of how relative brain size (read: brain to body mass ratio) would even enhance cognition (and therefore the ability to adapt to a foreign environment), if it supposedly does as the two studies on mammals and birds Ursus arctos posted suggest. You only need to look at some figures for brain to body mass ratio and compare them (here->; for example, note ants apparently have far greater brain to body mass ratios than even we humans do) to realize that it doesn't correlate to intelligence at all, not least (but not exclusively) because it doesn't even account for the fact that brain size does not scale isometrically, but grows with negative allometry. At least encephalization quotient accounts for this, and even then it still isn't universally correlated with cognition, nor can you directly compare those measured for non-avian reptiles, birds, and mammals, as they are not measured in the same way.

And if brain size is what determines how well an animal would do in a given environment today, how did so many non-avian reptiles, amphibians, and fish get by and adapt to today's ecosystems while retaining relatively small brains? If such animals can easily coexist with big brained mammals and birds, why the hell would an animal from the Mesozoic not?

And a completely unrelated thing that just particularly stuck out to me (it does not address his post holistically): he mentions Homotherium's penchant for hunting mammoths. Homotherium was not only not anatomically optimized for hunting and killing even proboscidean calves (link->), but it was also empirically demonstrated to be a generalist, not a specialist, predator. Isotope analysis suggests that it was hunting more yak than anything else, but also included bison and caribou, with less muskox, mammoth, and horse in its diet (Bocherens, 2015). So...yeah. Even though Gorgosaurus obviously did not evolve with proboscideans, I would think a ~2.9 tonne theropod that specifically evolved its colossal size to hunt megaherbivores would be much more of a mammoth killer - of 2-4 year old calves all the more so lol - than a far smaller generalist predator not even anatomically suited for hunting them.

[creature386]

Okay, I must have confused his mega-post here with another mega-post in a similar thread.

Too bad I can't check.

At least the question of "did the EQs of birds and mammals show a trend of increase over time?" makes for an interesting one to ask Professor Google about.

[all]

Too be honest I have very little information on why it happened. Although I have some limited knowledge on what has happen. And what changes in the biology of some creatures were needed and often times those needs were met  to achieve higher cognitive abilities. I just wish to join this particular conversation to expand my knowledge about this particular point even though when I was a kid I was not particularly interested in Holocene from paleontologist perspective but the part about why cognitive abilities became so much more advanced is very interesting.

One thing that coincides with advancement of cognitive abilities of many species is disappearance of megafauna so what ever caused the disappearance of megafauna could be responsible for improvement of intelligence of animals and humans as well. But this is just a guess.

As too what happened. Omitting the fact that brains of birds such as crows and ravens are very dense (although I'm not sure whether it came to be during Holocene or before) which is obviously big part of intelligence.  

Changes that to me would be likely to take place ( keep in mind I don't have direct knowledge when those changes occurred  just how are the now and what is required to achieve this status of intelligence) other than increased size of the brain is increased size number complexity and diversity of astrocytes (type of glial cells in the brain) is also responsible for cognitive abilities of the brain. human astrocytes are larger, more complex, there is more of them, and there are more kinds of them than those of the mouse or even chimpanzee's. If those changes took place during Holocene we would have a good idea of what happened. As far as something that does may not require that much time to change because it already varies between individuals of same species not just species across the board would be relation between surface area of the cortex and thickness of the cortex. when person or I think animal as well is young they should have largest possible cortical surface area as possible while at same time smallest cortical thickness past middle age it should go in opposite direction smaller surface area but larger thickness. That just might be the reason why increase of the intelligence happened so quickly and suddenly. But why it happened I don't really have any idea. I still believe that although the fact that many animals became lighter and faster than before might not be the reason megafauna went extinct. Fact is that in many cases this did happen. Take wolves for example modern wolves are not as heavily build as dire wolves nor as strong but they are lighter and probably little bit faster. There is a good chance that their prey became faster. while some pray became smaller they became fester to larger extant than wolves were. The best strategy against prey that is faster and more maneuverable is to work together together which in turn requires more intelligence. But some animals continued to be large and strong or even keep their size but be faster and more maneuverable that before. In order to put down such prey even better cooperative strategies would be required. but there still remained lots of animals that don't hunt in packs and if faced with cooperating predators whether escaping them as their prey or competing against for a spot of top predator they had to become stronger but also smarter. This would start the chain reaction that would happen relatively quickly. (I'm aware of the fact that those kind of changes happen through the evolution not just doing Holocene but that might be in higher demand doing this era) Smartest dinosaurs just happened to be smaller faster and cooperative hunters such as deinonychus. If it was not for the meteor that changed the course of history there is a good chance that this trend would continue past Cretaceous. 

Of course I'm not a paleontologist and what I'm saying is just a guess work as far as why did those changes happened. but I hope that some knowledge about what happened will also give insight to why.

  

[creature386]

Elephants and whales are among the animals Infinity Blade listed and they are about as large as animals get (if we ignore dinosaurs).

Besides, paragraph breaks would be nice. I skimmed that wall of text which is why I apologize for any possible misunderstandings in my reply.

[all]

Elephants are related to mammoths right. Mammoths are larger than elephants.

And they are the ones who went extinct  replaced by smaller faster species of similar kind. 

As far as whales they remained basically the same I never said that change would happen in all cases. 

If they did get smarter than that is because intelligence is always a good thing to have. 

Nor did I say that animals would get smaller in all cases ether, some might remain the same or even become larger. 

However animals getting lighter and faster ( not necessarily smaller) is a basic trend

I'm not a  scientist of any kind so what I said might be wrong ( as I stated it)

I also believe that what I said about what likely happened to the nervous system of those animals might shed light about why it happened

At least I would hope so, again I could obviously be wrong as far as this particular subject even train scientist aren't sure what happened





 

[creature386]

Well, the fact that mammoths went extinct while African elephants didn't doesn't prove the latter are smarter than the former. Especially as they weren't even subject to the same conditions. Either way, both mammoths and African elephants are larger and probably also smarter than the common ancestor of all elephantids, so the example still stands.

From what I see, we have animals all across the size spectrum among the top brains. We have mice and corvids at the lower end (size-wise), elephants and whales at the top end and primates somewhere in the middle. We certainly don't have enough data for a rule like "to get smarter, you need to shrink (or grow)". There is an optimum size range for sapient creatures (somewhere between dog-size and bear-size, IIRR), but "exceptional intelligence", as defined in this thread, covers animals from mice (or corvids, if these don't count) to whales.

[Infinity Blade]

I thought the top tiers, i.e. corvids, parrots, dolphins, elephants, and primates, were actually more or less equal in intelligence? Or are you just mentioning the tremendous variation in size?

[creature386]

I have no idea how I could write "intelligence spectrum" rather than "size spectrum". Fixed that.

[all]

Keep in mind I said lighter faster which might be a reason why teem work became important. 

Larger and faster prey. 

To catch it requires even more teem work

The reason why I used example of smaller is because smaller generally means faster as I stated speed and ability to evade predators is what were my main points

Smaller size was simply something that sometimes leads to greater speed and maneuverability which in turn requires more teem work from predators

More organized teem work requires more intelligence

But to avoid predators that work together better than before one needs even more intelligence by the prey

That starts a chain reaction 

As I stated I'm not a scientist and this is a difficult question even for them. 

This was simply one possibility I could think off on the fly.

Main thing that I wanted to contribute to this conversation was what exactly is required for the development of higher cognitive function.

That in turn could lead someone more knowledgeable than myself about changes in environment and over all conditions of the Earth at that time to derive at a possible answer. And than based on their knowledge to go further into the subject which might allow me to contribute from that point on. 

[Infinity Blade]

Wasn't sure where the best place to put this was, but this Quora answer by a developmental neuroscientist is an interesting read.

Why aren't elephants the smartest animals since they have the most neurons?

Because Minecraft

We often hear 'bigger is better' which might be true for pay-checks but not for other things. I’m of course talking about brains, what else? Nature has an astounding diversity of life, each with a unique brain. Some of those brains grow to be massive organs, like that of the African Elephant with a 5kg brain (11lbs) and 257 billion neurons. Some brains stay tiny, like that of roundworms which comes in at only a fraction of a gram with about 300 neurons in total. Humans rank in between, with a 1.4kg (3lbs) brain and give or take 86 billion neurons.

That begs the question, if humans are outranked by animals such as elephants, why are we the self-proclaimed smartest creature on earth? How is it that an elephant with almost 3 times the number of neurons isn’t laughing at our struggle with quantum mechanics?

Like a late night news-report, the reason might surprise you. To put it bluntly, humans aren’t all that special. Like mentioned above, we don’t have the biggest brain with the most neurons. Nor do we have the brain with the biggest surface area; dolphins beat us there with their amazingly complex brain folds. We get a bit closer if we take body size into account, but we’d lose from a marmoset (a sort of small monkey which honestly isn’t all that bright). A new measure was developed called the ‘encephalisation quotient’ (EQ), which takes into account that the relationship between brain and body size isn’t linear. It’s a whole formula, but it gave us what we needed for our ego, we were on top! Based on our size we have a brain that is 7 times larger than it should be. Sounds great for us, but the measure failed a bit for other animals. The rhesus monkey should be smarter than a gorilla if we were to believe their EQ, which isn’t the case. That puts us back to square one.

Humans don’t stand out that much in general, except when it comes to intelligence. Absolute brain size isn’t what makes us smart, neither is surface area, EQ, or neuron density. Then why is it that an elephant, with a huge brain and more neurons, isn’t as smart or even smarter than a human? This is where neuroscience and biology get a bit tricky, an example might help.

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Consider the fastest supercomputer in the world. At the time of writing, that is the Summit made by IBM. It has an impressive 9.216 CPUs, 27.648 GPUs and can make 200 quadrillion calculations per second. For comparison, it would take every person on earth working together, doing 1 calculation per second for almost a year to do what this machine can do in 1 second. It is set to model the universe, explore cancer, and figure out genetics on a scale we cannot imagine. But can it run Minecraft? No it cannot. Yet my old i7 quad-core laptop can run Minecraft just fine. Weird isn’t it, an immense computer with more memory and processing power than fits in my apartment can’t run a simple game that my rickety laptop can? So much for “super” computers.

The truth is, the thing isn’t designed to run Minecraft. It’s made to run those complex astronomical and biological models, while my laptop is designed to run games and various other tasks useful to me. I’m sure with some fiddling you can get any game running on those systems, but you’d definitely get in trouble for that. When comparing brains, the absolute neuron count isn’t the only thing we need to look at. Just like absolute processing power isn’t the only thing you look for when you need to play Minecraft. What’s in a machine, how it’s connected, how it interfaces, all change depending on a computer’s purpose.

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Human brains and Elephant brain are different in more ways than one. Different parts have different concentrations of neurons for example. Despite having three times as many neurons, elephants only have a third as many neurons in their cerebral cortex. The cortex just so happens to be the part of the brain we associate with a lot of “higher cognitive functions” and intelligence. All those elephant brain cells are concentrated in other areas, like the cerebellum which is used for movements (that trunk does look very capable).

The way the brain is put together is another factor. We estimate that Neanderthals had bigger brains than us; they had the capacity for a 1600cm3 brain. When researchers recently grew some Neanderthal brain-matter, we saw that they were very different from our own. Human mini-brains were nice, smooth spheres, whereas Neanderthal brains were more like popcorn. The consequences are still not clear, but it does bring us to this point: brains are complicated. Brains aren’t homogenous masses of neurons and support cells. Brains have structure to them, neurons form columns and layers, have specific pathways to send and receive specific information. The way neurons are structured and connected affects what and how they process information. Different animals have different needs, different senses, and different bodies. Brains are formed to deal with all of that. An elephant needs to control its trunk to get food, not solve math problems to get good grades.

As mentioned in the beginning, nature has an astounding diversity of life and brains. Those brains have been sculpted by evolution over millions of years, and evolution doesn’t care about intelligence as much as we do. Evolution is a process without goals; instead it takes more of a “good enough” approach. An organism has to function within its environment. For our elephant, an elephant brain is absolutely perfect for doing elephant things, it’s the pinnacle of elephantness.

Humans had different survival tactics and evolutionary challenges. We didn’t have claws and weren’t very big and strong, instead we were smart and social. In evolutionary terms we bet everything on our brain, which is reflected by our cerebral cortex. Unlike other measurements, our cerebral cortex usually comes out on top compared to other animals. Even when compared to other primates, our cortex is astounding (more so in organization than size). It does require a lot of fuel, making it very reasonable to assume we beat other primates in the intelligence game because we started cooking. But that’s a story for another day.

Intelligence is an elusive concept; we don’t really know for sure what makes one species smarter than another. It’ll be a while before we have definitive answers, but we do know it has to do with a lot of factors. Brain size, number of neurons, number of connections, different structures, densities, how they are connected, they all play a role. No single measure can explain why some animals are smarter than others, let alone why some humans are smarter than others.

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An elephant is not as intelligent as a human, because an elephant brain is formed and wired to do elephant things. Just like a supercomputer isn’t made to play Minecraft, but rather focuses on simulating supernovae. Human brains do human things instead of elephant things; in fact we make terrible elephants.

It’s not the size of the brain that matters; it’s how you use it.

www.forbes.com/sites/quora/2018/09/12/elephants-have-the-most-neurons-why-arent-they-the-smartest-animals/#2a7579d46afb

[Infinity Blade]

Just now I've had a discussion on a Discord server on what environmental conditions make an animal extremely intelligent (like in the clades mentioned above), and whether or not the Pliocene-Holocene is really exceptional in its conditions that beget high cognition.

My position was that the idea that relatively recent/modern times are so atypical and exceptional in that only they have ever allowed for the evolution of highly intelligent animals is not a given at the moment. If recent times are atypical in their conditions for highly intelligent animals, then we do not know what those conditions are (and we currently do not have any reliable methods of estimating the intelligence of fossil animals for whom there are no sufficiently close living relatives from which we can infer intelligence via phylogenetic bracketing). Further study is needed to truly confirm the idea that only recently have extremely intelligent animals evolved. After the discussion I still hold this position.

(Just to be clear, I'm not talking about civilizations before us, which I'm sure never existed on Earth before us. If I wasn't clear before, I'm talking about animals as intelligent as elephants, cephalopods, apes, cetaceans, parrots, and corvids.)

A couple things I've said (that I don't want to forget, so I wanted to save them here).

See, that's the thing, I can't help but look at that with skepticism. If exceptionally intelligent animals (like, elephant, corvid, etc. level) have only ever existed recently and now, in all of the millions of years animal life has existed, then these are highly exceptional and atypical times. Maybe that's the case, but if it is, then we don't have an explanation for why.

The fact that a handful of animals in this small slice of time are extremely intelligent and became so independently just raises more eyebrows to me. There are like, what? 6 clades that independently became highly intelligent (elephants, apes, dolphins, corvids, parrots, octopi I think?). Granted that's far from representative of all animal diversity, but that's still a handful. So if the Holocene and the few million years before it are really that atypical, then they're even more so in that that many groups independently became so intelligent.

Maybe like [username withheld] said there are reasons but we haven't discovered them, or...maybe those reasons don't exist and these aren't exceptional times. It is something I'd like to see studied more, but for now at least, I don't think we can conclusively say the old=stupid trope is necessarily true.

Any comments (whether objections or additions to what I've said) are welcome.

[Supercommunist]

Corvids are starting to use anti-bird spikes to protect their nests.

www.theguardian.com/science/2023/jul/11/crows-and-magpies-show-their-metal-by-using-anti-bird-spikes-to-build-nests

A lot of small animals that do well in urban areas may get an intelligence boost due to our influence.