A Brief History of Intelligence: The Neocortex and Evolution of Imagination

welcome to the Deep dive books Channel where we hope you find something valuable every

day let's continue exploring Max Bennetts a brief history of intelligence this is the fourth part of our

discussion before discussing each breakthrough of the brain Bennett always introduces The evolutionary history of

the relevant animals while reading these evolutionary histories one impression stands out the brain's evolution is

accelerating with each structural change becoming smaller yet the new functions resulting from these changes are

increasingly remarkable in the past it took billions or hundreds of millions of years to

achieve a breakthrough later breakthroughs occurred within one or 200 million years or even tens of millions

of years vertebrates even fish already possessed most of the basic structures found in today's brains subsequent

breakthroughs involved minimal structural changes but even a small change could lead to a significant new

function but the cost of evolving that new function was immense it would mean not only a drastic change in the

environment but also a global Extinction of species yes Earth's life forms had to

undergo several mass extinctions for us to become who we are today without those Extinction events we might still be some

kind of fish living comfortably in the ocean in the last part we mentioned that our vertebrate ancestors were a type of

fish living in the ocean from here on instead of saying our ancestors let's just say we referring to the species

along the line that eventually evolved into humans it makes the story more engaging initially we lived quite well

in the ocean so why did we move on to land we were forced to First plants began to colonize the

land because it offered better conditions for photosynthesis these plants rapidly

occupied the continents growing from a few cenet to several M tall like trees today if you had viewed Earth from space

back then you would have seen vast green land masses while this might sound nice it actually caused a big problem the

rampant growth of plants disrupted the balance between photosynthesis and aerobic respiration the plants consumed

carbon dioxide and produced oxygen at such a fast rate that the Earth's carbon dioxide levels plummeted leading to

global cooling and it wasn't just a little cold the oceans froze making it difficult for life to

survive this led to a mass extinction about 375 million years ago at the end of the devonian period ironically while

we are currently worried about having too much carbon dioxide it's worth noting that two historical mass

extinctions were caused by too little carbon dioxide perhaps plants are the ultimate force behind carbon

neutrality to survive this mass extinction many animals had to leave leave the ocean and move on to land this

is how we evolved lungs to breathe air it was a gradual process of adaptation at first we used both lungs and gills

allowing us to breathe in both air and water we stayed near water sources on land and gradually we lost our gills our

fins turned into Limbs and we became land dwelling tetr Pods at this point our ancestors faced a major Divergence

some remained coldblooded and became the ancestors of today's reptiles while we evolved into warm-blooded

animals this strategic Choice had both advantages and disadvantages the benefit of being

warm-blooded is that our body temperature remains constant allowing us to stay active even when the temperature

drops at night this means we could hunt at any time in contrast reptiles body temperatures drop with the nighttime

chill making them sluggish and difficult to move so when night falls don't they all become easy prey for us

however the downside of being warm-blooded is that we require more food to maintain our body temperature

whereas reptiles need less it turned out that this strategic Choice was initially correct we evolved into therapsids which

were about the size of a tiger and looked somewhat like lizards we even invented fur to keep

warm at that time the land was rich in food and the often sluggish reptiles were no match for us for the next 50

million years we ruled the world life seemed good until about 250 million years ago when Earth experienced another

mass extinction this was the most severe Extinction event in Earth's history where 96% of marine species and 70% of

terrestrial species died within 5 to 10 million years scientists don't know the cause of

this Extinction it might have been an asteroid impact volcanic eruptions or something else this Extinction nearly

wiped out the therapsids because food was so scarce the reptiles which required less food were more likely to

survive they evolved into Dinosaurs the world that followed belonged to the dinosaurs they would

dominate Earth for the next 150 million years it seemed that the reptiles had the last

laugh but fortunately some of us survived to survive in the cracks of the dinosaur world we developed two

characteristics we lived in Burrows and the most significant trait was that we became

smaller this animal is scientifically known as codons we went from being the size of a

tiger to the size of a mouse we became so insignificant that we didn't dare leave our Burrows during the day we had

to wait until the cold night when the dinosaurs were less active before venturing out to find food initially we

only dared to eat plants but we eventually progressed to eating insects and some of us even learned to climb

trees we once had a glorious moment but now we had to endure we survived like this for 150 million years without any

hope of seeing the light of day yet the gods of evolution favored us once again during those long ancient nights we

quietly evolved from therapsids into mammals we gained a competitive Advantage when it comes to muscle

strength and speed as mammals we were far inferior to dinosaurs and birds it was extremely dangerous for us if we

were discovered but our advantage was that we could strike first we sometimes hid in Burrows sometimes in trees not

provoking anyone like submarines waiting for the right moment when a nearby insect or other prey appeared and the

dinosaurs and birds were at a distance we could quickly make a move capturing our prey and returning home before they

even notied isn't that advantageous strike first but take note to accomplish this you need two important conditions

the first condition is that your vision must be excellent this only matters on land in water no matter how good your

vision is you can't see far so playing the submarine trick doesn't work that's why fish don't study this technique but

on land even though dinosaurs also had good Vision they couldn't strike first this is because their brains lacked a

capability that only we mammals possess this this is the second condition the ability to

plan before launching an attack you need to plan you can't just act impulsively like

reptiles how far is your prey how far is the nearest dinosaur which route will you take if your charge startles the

prey can you predict where it will run is that direction safe for you what's your escape plan these are things that

regular vertebrate reinforcement learning can't handle reinforcement learning in involves learning by doing

acting impulsively when emotions drive us and responding to situations as they arise this approach works well in safe

hunting environments where failure isn't a big deal but now we find ourselves in a dangerous environment where we must

withdraw safely if we miss our strike this is the difference between street thugs and professional assassins

if you can plan before taking action then you're not operating with just a lizard brain to plan our brain must be

capable of simulating the environment we need to run through our actions in the simulated environment of our brain

before taking them of course this requires a fast processing brain this is our advantage as warm-blooded animals

unlike reptiles that slow down when it gets cold so that's not an issue but simulation isn't just about fast brain

processing to simulate you need the ability to imagine you you must be able to generate an environment in your brain

and interact with it fish and reptiles still lack this ability although Birds later evolved this capability

independently this is a superpower arcade dwelling mamalian ancestors for some unknown reason evolved a new cortex

layer on top of the original brain cortex it was this new cortex that gave us the power of

imagination from the earliest vertebrates a type of fish to the first mammal spanning hundreds of millions of

years our ancestors went through various changes in appearance body organs and even living environments but the changes

in brain structure were minimal the neocortex was the only new development early mammals had a small neocortex but

now in the human brain the neocortex occupies 70% of the total brain volume the neocortex is only 2 to 4 mm thick

but it has a large surface area if you unfolded it it would cover about 3 ft roughly the size of a small table it

exists in the brain through layered folding the images you typically see of the brain are mostly the

neocortex the neocortex doesn't feel like something a carbon-based organism should have in the mid 20th century

Vernon Mount Castle later known as the father of Neuroscience discovered that the neurons

in the neocortex as well as their organizational structure are completely uniform across the

neocortex the entire neocortex is essentially a result of replicating the same microcircuit over and over again in

today's AI terms this is called scalable if M Castle had seen modern AI he would immediately say that the neocortex is

essentially an AI neural network this is the approach of silicon based life other regions of the brain have fixed roles in

the neocortex there are areas dedicated to Vision hearing touch pain taste movement language and even music however

all these regions operate with the same circuits and computational methods their differences lie only in the input and

output for example the visual area of the neocortex processes visual signals but if a person is blind and lacks

visual input this area doesn't remain idle it gets reassigned perhaps to process auditory signals which explains

why blind people often have enhanced hearing this is a form of general purpose

computation even more similar to AI the neocortex engages in unsupervised learning in nature animals can't rely on

supervised learning because there's no teacher to label every object they have to figure things out on their own the

neocortex does this much like training a GPT model today it reads part of the information generates the next part on

its own and then compares the generated information with the actual data reinforce ing what's correct and

adjusting what's wrong for the brain generation means simulation which is essentially

imagination generative AI has two steps training and inference it can't generate information while reading it

simultaneously and our brain works the same way you can't read a book and imagine yourself having breakfast at the

same time input and Imagination must be separate before reading this book I never realized that our brains can't

simultaneously receive information and imagine a different scenario now it seems remarkably similar to

Ai No One fully understands how the neocortex generates information just as no one knows how mammals evolve this

structure we only know that it excels at simulation it can simulate various inputs enabling us to imagine a scene or

even a concert and allowing us to plan actions before executing them this is why we are so good at filling in the

blanks why we are prone to false memories and why we dream imagination is the third major

breakthrough in brain intelligence that's it for today's content in the next part we'll discuss model

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