Part I - What is it about Sapiens?

So much confusion about what is unique about Sapiens. We humans definitely think we are special. But how? Let's start with the name of our species - Homo Sapiens, which is Latin for "Wise Man". Anyone looking at Human History would be hard put to argue that we are wise... The only thing we can conclude from the name is that modesty is not one of our species' defining traits! (1)

We talk a lot about how we are smart, but as we shall see we are not that much smarter than other species. We are also social, but so are many other animal species. What is it about Sapiens?

Warm Blooded

As noted by Patricia Churchland (2), professor of neurophilosophy at UC San Diego, the story of how smarts emerged in evolution starts in an unexpected place, with the appearance of warm-blooded animals some 250M years ago, at first as small reptiles (3). Warm blooded animals enjoyed a huge advantage over their cold-blooded brethren – they could hunt and forage in the cold of night, without the warmth of the sun, a time where their reptile cousins were immobile and not a threat. The nocturnal niche became entirely their own. Likewise, they could survive in cold climates, in areas beyond the range of cold-blooded animals, including big dinosaurs. And they could survive in very hot climates, thanks to the ability to self-regulate and maintain body temperature.

The capacity to self-regulate body temperature is known as Endothermy – and Endothermy turned out to be a very, very big deal in evolutionary terms. Over long, evolutionary time, endothermy resulted in a series of changes that produced smart, social animals – mammals and birds – that are wired to care not just for themselves, but also for others. How did the capacity to regulate body temperature result in smarts and sociability?

Warm-blooded animals have to consume 10 times more calories than cold-blooded animals to survive.

​It turns out that while endothermy brought huge advantages, it came at significant cost. Compared to cold-blooded animals, endotherms have to consume 10x the number of calories in order to survive. The basic reason is simple: warm-blooded animals need a lot more energy to maintain their warm body temperature. The largest animals on earth spend most of their day eating to fuel their body heat. Cold-blooded animals like reptiles can go without food for days, whereas mammals would rapidly starve to death.  To cope with the exceptionally high calory need, evolution’s answer was smarts as a survival strategy.

Smart Mammals

Being smarter and flexible is a key survival strategy for mammals (and birds). Being smarter in this case means having an enhanced capacity to understand the environment a mammal lives in – and to use that knowledge to be more effective in foraging, surviving, and mating. It is the ability to learn from experience and from observing and imitating others – being smarter about picking suitable mates, getting better at finding edible and healthy food, and having the flexibility to adapt to changing environments.  This latter point is crucial in terms of evolution – for instance, the asteroid that collided with earth about 60M years ago caused a mass extinction of large animals, wiping out dinosaurs – but small mammals managed to survive and adapt to a drastically different environment.

Mammals are Big Learners compared to other animals. After birth, mammals' brains grow as much as fivefold, and build intricate neural connections to encode what is learned. Having the flexibility to build many new connections means that mammals brains are immature at birth – to maximize learning, newborn brains wiring is minimal at birth. Mammalian babies are immature at birth and will certainly die without care. Evolution’s answer was a deep drive to care for offspring in all mammals. We will come back to the implications of this key mammalian trait a bit further on.

Neocortex and its layered structure

​How are mammalian brains wired to enable maximum learning? The neocortex is the crux of the matter. It is an innovation that is unique to mammals and is about 200M yrs old. The neocortex has a layered structure which it uses to integrate sensory signals and extract higher level information to better guide survival and safety. As Patricia Churchland (4) notes the magic of the neocortex is that "it learns, integrates, revises, recalls, and keeps on learning”. And it does this while dealing with a flood of neural and sensory signals – for instance, infant human brains make about 10 million synapses (neural connections) every second! "The neocortex also enables value-based judgement, such as when to suppress impulses. A good example is learning to never run from a bear. Bears can run faster than any human (even Husain Bolt!) and will often give chase if you run".

​Imagination - a Key to Survival

The neocortex also gave our tiny mammalians ancestors a new superpower: the ability to learn before doing, by imagining and simulating actions before they occur. As noted by Max Bennett (5), about 225M years ago the cynodonts were small mammals that could resemble a mouse or squirrel of today. They were one of the lucky species that survived the Permian-Triassic major extinction event - which is estimated to have wiped out 70% of all land life, and 96% of all marine life. They hid in burrows and wandered the floor and tree branches in search of insects. A cynodont would look out from its burrow and see a tasty insect nearby, as well as the faraway eyes of a predatory bird. With this new cognitive ability, it was able to imagine going the different paths to get to its prey, chasing the insect as it tried to escape, anticipating the possible reactions of the bird - and pick the path most likely to succeed in being alive and well fed.

Artist rendering of a cynodont - by Julio Lacerda

Bennet notes that scientists are not sure why only mammals developed this capability. Speculation is that there were two key factors that contributed: the ability to see further afield (one can see much further on land than in the water; which might explain why evolutionary pressure ended with fish banking on very fast response to anything coming at them, rather than simulating and planning), and the fact that thanks to warm-bloodedness mammals brains could operate a lot faster than fish or reptile, and quickly perform the complex computations required for simulation. (6)

The neocortex was a major evolutionary breakthrough. It enabled mammals to leverage their imagination to survive - by engaging in vicarious trial and error, simulating future actions and deciding on what action to take based on imagined outcomes. This enabled them to predict the consequences of their actions and to plan actions to achieve a goal. Ancient mammals behaved more flexibly, learned faster, and had better self-control than other vertebrates at the time.

For the longest time people believed in a hierarchy of species, with humans at the top - from Aristotle's "scale of nature" to Christianity's "Great Chain of Being", such thinking was pervasive until it was abandoned by scientists in the early 20th century, based on evidence. The notion of a hierarchy still lingers on though. The thought that a breakthrough in intelligence and imagination came into being in small mammals in underground tunnels, in a desperate attempt to avoid extinction over millions of years dominated by dinosaur predators, should bring a healthy dose of humility when thinking about our place in the world!

Next: Are we the Smartest Species?

(1) Credit to Tom Phillips, author of Humans. A Brief History of How We F**ed It All Up for that fun point

(2) Note that much of the information reported here is based on Patricia Churchland’s book Conscience. The Origins of Moral Intuition, and Max Bennet's book A Brief History of Human Intelligence: Evolution, AI, and the Five Breakthroughs that Made our Brain.

(3) This likely happened as part of transition from water to land, and evolutionary adaptation to more variation in temperature and drier habitat. Recent discoveries seem to point to appearance of warm-blooded animals even earlier, perhaps 300M years ago.

(4) Churchland, Patricia. Conscience. The Origins of Moral Intuition. As noted above, much of this page is based on her book.

(5) Bennet, Max. A Brief History of Human Intelligence: Evolution, AI, and the Five Breakthroughs that Made our Brain. As noted above, much of this page is based on his book.

(6) Birds are the only other animals we know of who demonstrate a similar simulating capability. As highlighted above, birds are the only non-mammals who are warm-blooded; they evolved their own neural innovations in parallel with the mammals' neocortex.