Intelligence Evolved at Least Twice in Vertebrate Animals
quantamagazine.org
quantamagazine.org
Bird intelligence makes a lot more sense in that context.
The most compelling explanation for bird intelligence I’ve read[1] argues that it all stems from social needs. Birds, you see, form lifelong pairs. But they constantly cheat on each other. Keeping track of this cheating behavior, deceiving each other, hide their actions, predict what other birds know, understanding who will and who won’t rat them out to their partner, that’s why the intelligence developed. Then once you have intelligence, it proves useful for all sorts of things.
Many species of bird also use this advanced ability to keep track of who knows what for food. They’ll hide a stash for winter and find it all later. But it’s easier to remember where your friend hid theirs than to get your own. So a whole arms race of deception developed.
[1] The Genius of Birds https://www.jenniferackermanauthor.com/genius-ofbirds
Maybe there are two types of intelligence -- versus humans and versus nature.
But yes, there are of course many different kinds of intelligence.
It's probably wrong to directly compare these two types of specialization. However, we do have an interesting social experiment going on: China's bureaucracy leans towards engineering backgrounds while the USA bureaucracy leans towards legal backgrounds. You can see this in the strategies pursued by each side: China pulls large and small levers to acquire hard power (in the sense of manufacturing capacity, not just guns) while the USA has historically been better at pulling large and small levers to acquire soft power (and even though tension from the Triffin Dilemma is peaking again, that's still probably a fair assessment). The next decade will probably see a showdown that supports or repudiates the "engineer primacy" vs "lawyer primacy" narratives on the level of international strategy, even though both will obviously still exist and have primacy within their respective niches. Interesting times.
And I'm just following the original logic, so I don't see what's wrong here. If you are not happy about the conclusion, I politely point to the original post/reply.
I don't think anything I said about social vs asocial species applies to two members of a a single social species. I feel like this is one of those intuitive leaps that serves as a great reminder that intuitive leaps aren't usually good science.
Edit: don't mean to imply a contradiction with the social interaction hypothesis -- needless to say there can be multiple factors that drive evolution in the same direction...
Given that we probably won't need to worry about AI getting significantly smarter unless we put it with existential competition with itself.
A) at all
B) more than others
C) happened to pass on
this makes more sense, since its about sex
every other use of the same skill is happenstance
for example with C), in humans, cancer occurs mostly after sexual reproductive periods, so there is no way for that to have been weeded out of the population. Demonstrating that many non beneficial traits pass on alongside beneficial ones and its all happenstance.
When you dig into it, these outliers are often the result of an evolutionary arms race [1]. In teh case of the inland taipan, they are often prey for mulga snake and perenties, who have evolved immunity to their venom. So you've got a feedback loop where the taipan keeps evolving stronger venom to fight back against predators, who continue evolving stronger immunity to the same venom. Run that loop a million years and you get a snake who can kill a busload of people.
Human intelligence is another such outlier. I know it's popular to talk about how animal intelligence is underestimated but even so, human intelligence is just astronimcally greater than any other species. Sure a squirrel can find a bunch of nuts it buried. Humans have built machines and landed them on other planets. Our intelligence is orders of magnitude greater than any other species.
My pet hypothesis for years is that this must be the result of an evolutionary arms race within the species. Humans are a profoundly social species. We are mostly too fragile to survive in the wild on our own. The functioning survival unit of humans is a hunter-gatherer group. We are sort of like eusocial animals like ants.
But unlike ants who can mostly rely on simple chemical signals to tell which other ants are part of their anthill, we have to rely on social cues. There is a very strong incentive to be able to deceive humans in other groups and infiltrate or sabotage their group. If you're smart enough to sneak in, you can steal a lot or do a lot of damage. Likewise, there's an equally strong incentive to be able to suss those bad actors out to prevent them from doing that. The smarter you are, and the better you're able to remember people and describe them to others, the harder it is to get taken advantage of.
Turn that evolutionary crank a few hundred thousand years, and you get a species so smart that the only other animals that can possibly hope to compete with them in terms of intelligence are other Homo sapiens.
If we weren't so deeply social, I don't think we'd be so smart. We have these huge brains in order to navigate the fantastically complex social world which we have in turn created by having these huge brains.
And it obviously requires massive intelligence for written language and high fidelity communication.
Frans de Waal studied primates and defended just this hypothesis. He wrote a bunch of books, so you may be interested in reading at least some of them.
BTW, my pet hypothesis is the social roots of our intelligence is the reason why people mostly hopelessly dumb. They kinda go on intuition and it works in normal social situations, but when it comes to politics or science the intuition fails them. One needs to train their mind to stick to logic and rationality, without taking sides which seem the most beneficial for them. But training is hard and training can easily be overcome by the intuition, which is the natural way for brain to work. You need to keep your brain working against its nature to not lose your intelligence in situations which are not hierarchy games.
At the end of the day, all the achievements you've listed are not only the result of massive intelligence but opposable-thumb hands (for tool use and writing) and fire (for an easy early source of energy to runaway with).
If humans were just as intelligent but never had these, we'd never reach the moon or build machines.
So there's an evolutionary pressure to make venom as fast acting as possible so that the prey has fewer chances to injure the snake before dying.
Black mamba in Africa is in a similar situation. It's an arboreal snake, so its toxic venom helps it to hold on to the prey.
You have to remember that "bird" is not like "human", it's more like "mammal". Lots of variation between species :)
This reminds me of a backyard squirrel anecdote from a decade ago.
A squirrel would laboriously dig a hole and hide a nut in it, cover it with soil, and tamp down the soil -- until it noticed another squirrel watching it from the top of a fence, at which point it immediately proceeded to dig up the nut and carry it away.
-- Peter S. Beagle, The Last Unicorn
I also agree that it makes more sense that pressure to become smarter is linked to prediction and preservation, as they're fragile creatures. A wounded mammal could crawl inside its nest and heal, a wounded bird is likely a dead bird.
I recommend reading the linked book from a bird expert who has been studying this for her entire career. I promise it is much better and deeper than my comment here.
It links to 266 references (papers) at the end. I just checked
It's perhaps not a coincidence that humans have at least something in common with birds in terms of evolutionary heritage that predisposed us to covering vast amounts of terrain.
Not all modern birds are intelligent - some like chickens are clearly not, which is understandable because they don't need to be. However, the sheer variety of habitats and food sources utilized by birds (from raptors to penguins, ostriches to hummingbirds) would seem to indicate that generality and intelligence may have developed early as they were pushed to, and able to, explore new environments, and survive climate and other challenges over the millenia. Some birds like covids are still generalists and therefore highly intelligent, while others have settled into much narrower behavioral niches and have therefore lost it (or perhaps never had it).
In fact, the tone of GP implicitly acknowledges that intelligence has a cost, because the post implies that intelligence isn't likely to manifest unless there's a clear advantage (presumably because intelligence has a cost which needs to be overcome by an advantage)
The need for intelligence comes from being a generalist, needing to learn and apply a large complex set of situation dependent rules. This is why specialists like raptors, chickens, penguins are not renowned for their intelligence. A good outward sign of intelligence is playfulness, a trait evolved to put the player in learning situations to feed their intelligence. Animals like apes, dolphins and crows are all very playful. Eagles not so much.
So, yeah, I was correcting GP. If you don't like it, then too bad.
I read that bird brains have a high neural density (lots of neurons, packed tight). That's why they can be so smart, with such small brains.
Birds need a lot of energy for flying. They don't cook. They solved the energy problem by developing the most efficient mitochondria on the planet. They pay a fairly high price for that in terms of infant mortality, but I guess the ability to fly is worth it. It means when they aren't flying, they have a lot of excess energy to power an highly intelligent brain. They could then use that brain to detect when their mate was screwing around, and decide if it was worth ditching them.
That's all guess work of course. I'm no expert, just belly button gazing really.
<https://scp-wiki.wikidot.com/scp-1115>
<https://scp-wiki.wikidot.com/scp-1050> (not main subject, but what anomaly references)
<https://scp-wiki.wikidot.com/scp-4001>, then <https://scp-wiki.wikidot.com/alexandria-burning>
Birds have two. One feeds the other. Their field of view for binocular vision is often not large. They completely lack the power to "fill in" details of occluded objects the way that we can. Which is the true power of our vision outside of pure pattern recognition used to find sources of food.
It's that, and more. When I walk under the trees outside, the corvids at the top make a specific noise. I'm pretty sure they're telling each other "Look out, mammal on the loose down below!"
Birds, on the other hand, have a disting evolutionary advantage in making their brains as small and light as possible.
To me, this implies bird brains are likely to be much more efficient, both volumetrically and energetically. That's the more fascinating angle, IMO
Maybe the ours are getting more efficient too.
> Birds, on the other hand, have a disting evolutionary advantage in making their brains as small and light as possible.
I'm not sure about that. Not all birds are as clever as crows. Who knows if a few less grams of neurons is worth the "IQ" loss, and conversely who knows if a few more grams of neurons makes a difference in terms of survival? Not to mention that these animals must also have vestigial or ridiculously expensive organs or functions (e.g. peacock's feather), so maybe they are not so sensitive to weight or energy consumption. It is difficult to measure.
I've long been puzzled by the fact that if intelligence was such a big advantage - almost like cheating in our case - why is it not common? Well, for one thing we wouldn't have struggled a lot more to get to the top of the food chain. But Evolution is the process of adapting to an environment, and sometimes it selects what is "good enough". In a way flies are far more successful than us, because there are millions of flies for each one of us, and they are more likely to survive a planet-scale catastrophic event. Sometimes brute-force reproduction works better than more neurons.
Their brains also aren't structured similarly to ours in a gross sense, although the so-called "mushroom bodies" do appear to serve similar purposes to our cortical "gray matter," and if I recall correctly, there is some sense that connectome complexity scales proportionately with complexity of behavior, though I'm not sure how well this has actually been studied.
On a similar note, though their primary eyes aren't constructed at all like ours, they do nonetheless exhibit a "foveal" area of highest detail and resolution, in the regions of their eyes where it does them the most good - namely, ahead and below, the latter aiding in manipulation with palps, mandibles, and the front pair of legs. That's not quite the same as a brain per se, of course, but it does also point to the adaptive constraints under which evolution has occurred: as flyers who construct their own nests and who regularly must travel long distances to find all the resources a colony needs - or, as peripatetic mammals who came up grazing as much or more as hunting and use tools - good eyesight, memory, and dexterity are all very valuable, and thus it isn't a great surprise when such species that become successful on a cosmopolitan scale show extensive development of these traits. The infrastructure on which the trait is built may be independently of interest, but not being able to understand how such a small infrastructure gives rise to such global traits isn't an excuse for ignoring the exhibition of the traits.
In light of all that - plus the anecdotes that such a close and friendly interest in wasps would tend to yield - I've tended to think of intelligence in this sense, or capacity for same, as sort of "holographic" in concept: if you make a hologram on film and then cut it in half, what you get is not two halves of a hologram, but two complete holograms, each with lower resolution than the parent. I think brains scale the same way, such that what you get with a much smaller brain is not so much less breadth as less depth.
I don't really have a clear formulation of the concept, or not yet at least, but hopefully you can see at least a vague outline of what I'm reaching for. Or that I do, at least! Maybe we could think of it as the anthropic principle shorn of human chauvinism, if you like.
If another mass extinction occurs, we are toast (See "The Ends of the Earth"). Relatively minor ecological changes may even destroy us. Sapience has not yet proven to grant any long-term advantage.
(Assuming life arose on Earth only once. That seems like a convenient moment to start the clock.)
The caloric enrichment of food by cooking probably can explain this as well. We got smart enough to cook, which gave us more energy from less food to power the brain. At that point, the evolutionary advantage of metabolic efficiency matters less. It allowed early humans to continue developing on the same path, probably increasing brain complexity somewhat over time while not focusing as much on energy.
But I'm no biologist. I'm just guessing.
I wonder whether it is possible to increase their intelligence further -- e.g. what if they are really as smart as 4-5 years old in one generation and a bit more in the next? Is there a way to "eugenics" (I know it's a bad word) birds on intelligence?
Of course there is. Develop an intelligence test and remove the bottom x percentile from the breeding pool. Alternatively develop an environment that gives a competitive advantage to intelligence.
Edit: Historically, there were "hunting birds" kept by the wealthy. Even today, but they are much more rare than dogs. Training and breeding would be standard practice in that environment.
We already control dogs' sub-species, so let's say we decide to uplift dogs to human level intelligence. How long would it take? At what point does it become unethical to modify a species that is on the way to intelligence? What does an evolved dog look like at different stages of their human-forced evolution? A modern dog is what (very rough) equivalent to which stage of human evolution?
Let's say you breed a dog past toddler level intelligence, and a little more conscious, and communicative... How do we now feel about them having a lifespan of 10-15 years? It's already heartbreaking enough. Imagine if they were aware of their mortality and short relative lifespans...
And perhaps grateful that if they're here for a short time, they're blessed to burn all the brighter.
> Imagine if they were aware of their mortality and short relative lifespans...
Though you might certainly feel less grief, if there was less of them to lose in the first place.
[1] Ligotti, 2010
Having had dogs live with other dogs growing old and passing away, I think this might be a lower threshold than understanding (a subset of) human language. Surely even without humans, a pack of social animals has individuals getting sick and growing old, and that changes how they interact with each other. Elephants are known to keep visiting bones of relatives over multiple years.
I'm personally more surprised at how well my 12-year old mutt picks up new routines, and the words that are said at the start of the routine, than at the thought that she would know that everyone's getting older and will die at some point. I'm anecdotally actually quite convinced she used to live with older people before -- she comes to "take care of me" every time I cough or sneeze.
This is pseudo-science and a common misconception. There is no genetic reason or support for mandatory detrimental tradeoffs.
Historic breeding programs often allow side effects as a practical matter, but that doesn't mean they are detrimental or required.
Sometimes genetic difference is all upside just like a mutation can be all downside.
We might be willing to accept the side effects but that doesn't mean they won't inevitably occur.
With respect to wild parrots, it's not obvious that improvement is possible, let alone has disadvantage. Assuming it is possible, there are numerous reasons why it might not already exist. No advantage, low negative advantage, negative incremental advantage, and low probability are all possible reasons. Not every viable state has a viable incremental path to it.
Most genotypes or "random mutations" are totally neutral for an organism, but let's say that of the notable ones, it's 50/50 whether they will be "good" or "bad".
If we find the "good" smart parrot, it's likely they have some other "bad" stuff we can't see or just don't care about. When you keep inbreeding, that other bad stuff will be fixed along with the intelligence. This is purely a limitation of our knowledge of the genome and lack of other inputs. You can out-cross to reduce the bad traits, but you risk losing some of the intelligence too. Theoretically there is another bird out there that solves the "bad" trait without affecting intelligence, we just don't know which it is.
Nothing stops you from having a win-win-win. You could randomly find a bird that is super smart with rainbow feathers and the voice of an angel... It's just incredibly unlikely to roll all those attributes in one individual and keep them through multiple generations.
As to why wild populations haven't naturally evolved to be smarter, that is an entirely separate discussion about countless competing selection pressures and how genes spread through larger populations.
That isn't always true. We know in humans there are genes that depending on which variation you have, you will either be more social or have better memory. According to AI I'm thinking of BDNF (Brain-Derived Neurotrophic Factor), but digging deeper doesn't indicate that is correct. Either way there often are trade offs in genetics.
Though of course genetics is only one factor. How your are raised/taught also makes a difference.
Having trisomy 21 or exons in your myosin genes don't give you superpowers in another part of your life. There are people with excellent memory and social skills, and people that lack both.
By way of analogy, nobody would say that all possible airplane designs are equal and there are only trade-offs. Some are superior in every possible respect to others.
The appropriate response unknowns is not to declare that tradeoffs are always the case, let alone equal
A large parrot has around the same number of neurons as a beagle dog.
Combined with weight savings, this may allow their brains to work faster, which is useful for a flight computer.
Birds have other features which are superior to mammals. For example, their flow-through lungs allow for more efficient gas exchange.
However, having to fly means weight reduction has been a big driver of evolutionary compromises. A bird that can fly cannot carry large fat reserves around. They are not resilient when sick and often die quickly after the onset of visible symptoms.
Humans really are surprisingly strongly generalist, in ways many other animals are not.
A 200gram grain-fueled homing pigeon can maintain 60km/h for an hour. A cheetah can do that for maybe a minute.
I've always thought this is not really a fair comparison, as flying through the air probably requires way less energy than sprinting.
The mantra is "nuclear" or "regional" organization in birds rather than layers in mammals, but the anatomy [0, Fig 4] and electrophysiology [1] abstract this out in similar patterns.
> The mantra is "nuclear" or "regional" organization in birds rather than layers in mammals, but the anatomy [0, Fig 4] and electrophysiology [1] abstract this out in similar patterns.
Marsupials too! Sort of.
Generally, marsupials are mostly close to other mammals in brain structure, but they do have a fair bit less layers and some nuclear structures.
Comparative neuroanatomy in vertebrates is, like, super interesting (to me at least). It really goes to show off evolution and how her pressure is really towards more babies - however that needs to be accomplished.
It is science/speculative fiction, that started from the author wondering about a scenario in which humans had gone extinct 10k years ago, before we developed much, if any, material culture. He felt that had that happened another intelligent species 1M years later would have no idea that we had even existed (different story now, of course).
In the book, a discovery on the steppe of Khazakstan leads to revolutionary discoveries about very, very old intelligence.
The author has written several non-fiction books on animal intelligence.
"The Silurian hypothesis: would it be possible to detect an industrial civilization in the geological record?"
https://www.cambridge.org/core/journals/international-journa...
<https://scp-wiki.wikidot.com/scp-1115>
<https://scp-wiki.wikidot.com/scp-1050> (not main subject, but what anomaly references)
<https://scp-wiki.wikidot.com/scp-4001>, then <https://scp-wiki.wikidot.com/alexandria-burning>
How would the worlds have looked if some birds would have developed language and being able to transmit knowledge to sibling and children? Or was it the fact that we have hands that we evolved further? It is sometimes argued that language developed as part of mate selection. Bird vocalizations definitely play that role with birds.
Take ravens for example. There's one that hangs out in trees directly outside of my house now and then. It makes new sounds I haven't heard before quite often. I don't hear other ravens, so I'm not even sure it's trying to communicate. Does it have a social purpose? Is it bored? Do the variations express anything at all?
Yet being in a forest with them around, you hear all kinds of noises too, and they do it all together. They interact a lot. Though my experience is that they use fewer variations when they're together compared to the weird one outside of my house.
They seem very intelligent regardless. They're such cool birds.
Meanwhile most of the other birds around my house, as far as my ears can tell, just make the same sounds over and over. What does any of it mean?
As birds spread to fill many different niches, their vocalizations had to diversify so they could still find each other.
Complex mating displays (singing, dancing, nest building) are fitness demonstrations. They correlate to endurance, resourcefulness, memory, etc.
And of course, some behaviors may simply be vestigial.
Birds do learn from observation. Even from other birds and animals.
Moving past that to speculate though, I think Chomsky would point to two (surely somewhat syncretic) forces:
1. Evolution is not an exhaustive breadth-first search; even if an adaption would be advantageous, genetic affordances can make it unlikely on a finite timeline. Theres lots of speculation on why humans in particular were well-prepared to evolve language for internal deliberation and/or external communication, but it’s somewhat beside the point here.
2. Evolution works most quickly in reaction to environmental stressors. There’s something of a consensus forming around the importance of changing climates for our genus (i.e. why aren't there other apes in cold regions?), whereas birds were inherently afforded a much simpler answer to that stressor: migration.
All of that said, I think it’s important to highlight an under-appreciated fact: the only things we have ever observed using language are a) humans, b) possibly other Homo species like Homo Naledi, c) LLMs, and—as of the past ~week (!!!)—D) possibly Bonobos.
Lots of animals communicate using words/signs, and a majority (?) of plant & animal species signal to each other and others using scents, colors, shapes, body language, etc. But only the above four can intuitively synthesize those signs on the fly into contextual phrases — or, as Chomsky would say, “generate an infinite range of output from a finite range of inputs”.
It’s worth caveating that this is absolutely a subjective stance based on how you want to use “language”, and that a sizeable camp of linguists would disagree on that basis. But I think the underlying unique quality is important, so Chomsky is correct to single it out as “language” — otherwise, how would you even phrase the above question? Birds clearly have complex verbal and visual communication already, and “better communication” is vague and unsatisfying, IMHO.
So for the camp of linguists that disagree I do wonder what alternative theoretical foundation do they have.
https://www.researchgate.net/figure/Human-and-songbird-MNs-i...
I think it's just ability to learn based on whether there's more or less of something, in most cases. Which if you think about it, is an obvious skill all animals must possess in order to make decisions. And nothing new.
I don't think those studies are showing true "counting". For example as a person I can without counting tell if there's 1, 2, 3, 4 or 5 of something, I can tell how many characters are in shorter words on glimpse, but that's not counting. These amounts are just pattern recognition labels. However I can then use these in groups to do actual counting.
Animals certainly must be able to tell if something is smaller or bigger, because they must identify whether it's a potential prey, or a threat. Already this ability should lead to the ability of being able to differentiate between there being 1, 2, 3 or 4 of something.
There seems to be studies that are using this idea to prove that animals can count.
Ultimately these are the strength of certain stimuli and even a simple machine learning algorithm can produce different output based on the amount of that signal.
And then talking about planning and self-control. Many animals are willing to patiently stand still, waiting for their prey to make a move, I don't think it means that they are specifically "thinking" about it. A cat can patiently wait for the mouse when it notices the hole.
This is an indication that fᵢ in the Drake Equation [1] is probably closer to 1 than 0.
The last common ancestor of [humans] and octopuses is a flatworm that
trawled the sea floor 750 million years ago. This is the most recent
creature that we both have a direct line of descent from – it represents
the point at which we diverged down separate evolutionary pathways. To
illustrate just how early this was, this was 80 million years before any
animal showed bilateral symmetry – the familiar body plan with a defined
top and bottom, and right and left; 350 million years before tetrapods –
the first four legged creatures that gave rise to all birds, reptiles,
mammals and amphibians – came into existence; and 500 million years before
the emergence of dinosaurs.
Nice book about the topic is "The Deep History of Ourselves" by Joseph LeDoux.
https://www.amazon.com/Deep-History-Ourselves-Microbes-Consc...
You need to define what constitutes intelligent behavior and we certainly have some of this from studies of human evolution - e.g. tool use, emergence of art, burial practices, that kind of thing.
Also, could you give a more substantial answer than
>Behavior can be inferred from the fossil record.
... that's literally the question rephrased as a statement, lol.
A concrete example would be appreciated.
This leaves a lot to be desired, in my mind. Examples: * Soft tissue organisms may not be well enough preserved to be studied. * Can't evaluate intelligence in evolutionary dead-ends that no longer exist. * Limited evolution theory may miss mechanisms of how intelligence comes about, like maybe from something akin to a shared toxoplasmosis infection among different species rather than each getting there through a random walk.
The original technological breakthrough that has differentiated cephalopods from other animals was a shell that could be filled with gas, acquiring thus a controllable buoyancy.
The early cephalopods had a lifestyle similar with the modern Nautilus, floating freely in the water and gathering the prey around, unlike the snails and bivalves that had to sit on the bottom of the sea because of the weight of their shells.
The lifestyle of most ancient cephalopods, like ammonites, did not require a great intelligence, so it is unlikely that they had developed it. This kind of cephalopods have been dominant for a few hundred million years.
That changed only after the apparition of the ancestors of octopuses and cuttlefish, which have exchanged their protective shell for a greater mobility and which have begun to live on the bottom of the sea or close to it, where the environment was much more variable and challenging for a fast moving animal than in the free water, far from obstructions. This is when the high intelligence of cephalopods has developed, sometime during the middle or even towards the end of the Mesozoic era.
On the other hand, the intelligence of the vertebrates has developed a lot after they have conquered the terrestrial environment, which was much more complex than the marine environment, sometime during the Upper Paleozoic era, probably at least one hundred million years before the cephalopods.
Also, while your quotation is grosso modo right, it has a lot of details that are very wrong.
750 million years ago there were no animals whatsoever. Such ridiculous numbers are sometimes proposed by people who do not understand that the so-called "mollecular clocks", which are based on the frequency of inherited mutations in DNA, are not constant clocks. While the frequency of raw mutations in DNA varies only very slowly in time (e.g. due to the general slow decrease in the ambient radioactivity), only a small fraction of the mutations are inherited, because most mutations have bad effects, especially in more ancient animals, which had less redundant DNA. How bad are the effects, depends on the existing competition. When there is no competition, because either a new environment has been conquered or because a catastrophe has wiped out the competition, than bad mutations may not matter and their carriers survive, so their descendants inherit those mutations (after collecting additional mutations that undo the bad effects). That is why all the divergences between animals that have occurred after catastrophes or after arriving in new environments appear like they could be extrapolated towards much earlier intersection points, which are always in conflict with fossil data.
Moreover, the common ancestor of vertebrates and mollusks was a worm, but it certainly was not a flatworm. There are several unrelated kinds of worms that are flat, but their flatness is caused by a more recent evolution. Several groups of worms have been very small at some time in their past, when they became simplified by losing partially or totally some of their organs, like the circulatory system or respiratory system. Sometime later, they have evolved again towards greater sizes, but in all cases of evolution reversals identical developments are extremely unlikely. Normally different solutions for the same problem are found. So most "flatworms" are flat because with this form they no longer need the better respiratory/excretory/circulatory systems that their ancestors may have lost.
The common ancestor of vertebrates and cephalopods was some kind of worm, which lived significantly less than 600 million years ago, during the Ediacaran, which had bilateral symmetry and which probably ate only microscopic food filtered from the sea water.
Bilateral symmetry is the symmetry that is normal for any mobile animal living on the bottom of the sea, while radial symmetry is adequate for a sedentary animal. While for echinoderms there is no doubt that their radial symmetry has evolved from a bilateral symmetry, even for cnidarians there are good chances that their radial symmetry has also evolved from a bilateral symmetry of their ancestors, after the polyps have lost mobility as adults.
Even the fixed sponges, which may have no symmetry, might have evolved from mobile ciliated ancestors.
The traditional view of evolution was that all simpler forms must be primitive and all complex forms must be derived, but now it is clear that evolution towards the maximum possible simplification for a given lifestyle is more frequent than evolution towards more complex forms. Because of that, many groups of animals that were thought to be very primitive, like some of the flatworms, may be highly evolved, but towards simpler organizations.
It's an utter bombshell if true. It means intelligence isn't "difficult" for evolution to arrive at, significantly increasing the odds of other intelligent life in the universe.
So also outside of mammals and birds there are some cases of brain evolution towards greater complexity, even if not reaching the typical mammal/bird level, and which are likely to also correspond to a somewhat different brain structure.
(Off topic, in my opinion, "reptiles", is a term that is properly applied only to lizards and snakes. Not only crocodiles and turtles are more closely related to birds than to lizards and snakes, but also none of them are crawling, as implied by the word "reptile". Actually the present crocodiles are awkward on land only because they are secondarily adapted to an aquatic life. Their terrestrial ancestors were much more agile, as still demonstrated by some crocodiles that are even now able to gallop.)
Most fish (bony fish) are more closely related to us than they are to sharks and other cartilaginous fish. Technically we're all air breathing walking bony fish.
Easy to forget that “fittest” is only relevant to the environment/context you are living in - if intelligence does not make you “fitter” for that then it will probably disappear.
Bob: It's about the survival of the fittest.
Alice: Fittest with respect to what?
Bob: Survival.
So, survival of the fittest to survive, or what survives, survives.
It is utterly banal, but in popular culture, it has been "elevated" into a deepity.
For me survival of the fittest just means that with high probability those genes will survive who have a high probability to survive in an evolutionary setting. Is this trivial? In this wording it is trivial. But it can be useful. (And also it is not that trivial in a different wording. Just like other theorems, e.g. the theorem about the perpendicular bisectors of a triangle's sides. If a point O is equal distance from A and B and B and C then it is equal distance from A and C. Tautology, circular, assumption, name it what you want, it's math.)
It's almost a circular/tautological description ("survival of the survivors"), but "fittest" does at least allude to why some survive better than others (better adapted to prevailing environment), as well as the fact ("fitt-EST" vs "fit") that it's a competition for limited resources. Fitness is a matter of degree.
Many animals have no need for intelligence/generality since they have a very limited behavioral niche (e.g. herbivores, crocodiles, sharks), so it wouldn't have evolved in the first place, but even for those that do the benefit has to outweigh the cost.
If every animal was a generalist they they'd all be in competition with each other, so I'd expect if you ran simulations you'd find that an ecosystem full of species that don't compete head-on is more stable, and therefore likely to result.
At the time of writing this comment, there is not a single reference to Children of Time in this thread other than the one you have added.
What are humans? If we focus on early-noticed similarities with Great Apes, people often took to saying "We are the tool users", but "We are the builders" is maybe just as accurate. We produce not just jackhammers, but skyscrapers. Tool users modify their environment adaptively for utility, builders modify their environment adaptively for utility. The evidence is in the works.
Building a stacked stone house requires creating an abstract concept of a future dwelling you would like to have, figuring out how the wall works in that dwelling, modifying the wall according to the layout of the terrain, finding and modifying the appropriate piece of stone that works in the correct position, and then iterating on this piece by piece as each stone provides a slightly different opportunity for the next stone. It requires persistence in pursuit of that abstract goal much longer than routine biological feedback loops; We're talking about a delayed gratification "Marshmallow Test" because you don't get to enjoy sanctuary from the weather until you're done. It requires a consciousness of the environment, the available tools, one's one's own limitations, and the shifting outlines of a hypothetical future. There's literal Gantt Chart type prioritization and preparation involved. I don't see how this could possibly be less complex cognitively than a mirror test.
A number of of animals build nests, piece by piece in the fashion of a human rather than purely through biological secretions. I argue that all of them, even the really weird ones (eg ant nests), are in one sense intelligent.
I think the text plays more on hammering the "nothing makes sense in biology except for the light of evolution" thing than on the roots of intelligence.
The purpose and definition of intelligence have always been a critical point in evolutionary biology.
No mention of the foxp2 gene and the peculiarities of both human and bird variants? Seems like this would open a point for an opposite conclusion (there is a common root if you consider language part of what constitutes intelligence).
In the sixties, birds were girls, cats were boys, and everyone was kind of an asshole. Why should I trust any kind of research that started back then? :) If we're gonna be weirdly anacronistic, let's at least be clear about it. I am more of a 2025 person.
The thing that jumped out at me in the article was this implied definition of "intuitive":
"In mammals, brain development follows an intuitive path: The cells in the embryo’s amygdala region at the start of development end up in the adult amygdala."
So let me see if I understand: Here is rock on hill. Rock stays on hill, or rock falls down hill. Because it's intuitive.
I'm not sure I agree that that's what "intuitive" means.
https://www.audubon.org/magazine/november-december-2014/stal...
We've trained chimps and gorillas for decades and they have never asked a single question
Some AI startup needs to get this in their marketing, stat.
There is of course a lot of variation in which things the model emphasizes and how much simulation is done, but that's the gist of it, and there are lots of ways to measure it in animals.
For starters, what is intelligence? Because defined one way, you could attribute it to virtually anything that responds to the environment in some way. Against mechanistic presuppositions, you'll be stuck with the impossible Sisyphean task of defining it at all (good luck weaving intentionality into mechanistic metaphysics; it is no accident that Descartes believed that non-human animals lack consciousness - he viewed them in mechanistic terms!).
Or consider...
'they could help us step “away from the idea that we are the best creatures in the world"'
'“We are not this optimal solution to intelligence.”'
What is meant by "best" and "optimal"? Without telos, you cannot speak about anything being best or optimal. There is no ordering measure. These are defined with respect to how well something attains an end. Is pencil A better than pencil B? You can answer that once you define what it means to be a pencil, because then you can define what it means to be a good pencil. But is a pencil better than an eraser? Meaningless question w.r.t. what is intrinsic and essential to each, as they are two different kinds of things with two different ends. Measured against human purposes, i.e., purposes extrinsic to the things themselves? You could say that the pencil is superior, as it more directly and fully contributes to the human end of communication or drawing or whatever, while the eraser plays a supportive role. Or consider perhaps some kind of absolute ontic hierarchy (at the very least, human beings can do whatever any other animal can through technology, something that permits the extension and determination of the human power to act).
"What are the building blocks of a brain that can think critically, use tools or form abstract ideas?"
What is an "abstract idea"? How does it differ from a concrete image? For example, let's say that after a squirrel perceives a tree in its senses, it remembers this perception. Is this an abstract idea? What if this squirrel sees another tree and, through its squirrel brain, is moved to behave with respect to it in a manner similar to the first tree. Does that involve abstraction? Does similarity of image entail abstract ideas? If the abstract idea of "Tree" is not an image, not a similarity between images, and therefore not particular but a universal predicate, for instance, and the brain itself is concrete, then how can brains entertain abstract ideas that escape concreteness and particularity?
Some will no doubt claim that answering these questions is precisely what neuroscience seeks to do, but this is confused. Yes, neuroscience can shed light on certain neurological phenomena, and that's great. But neuroscience also operates within "meta-neuroscientific" parameters and makes use of its (often hazy) notions in a way that undermine its coherence. These require philosophical chops to untangle and analyze.
[0] https://edwardfeser.blogspot.com/2011/01/against-neurobabble...