Meat the Brain that Became Sapiens

As we continue on our journey through Part I of “Your Brain on Meat” in the Brain Food Series, we “meat” the brain that became sapiens.

Thanks to six years of Latin training, I can tell you that “sapiens” means wise. And while years of study to learn a “dead language” may not seem wise, to me it signifies the most important thing humans possess that no other animals even comes close to. Language.

And as well see, human’s unique ability to communicate is made possible by the most unique brain of all animals, a brain that made us sapiens.

Brain Food Recap

In Section 1, we saw how selective pressures coupled with a persistent feedback loop between climate, food availability, and the advantages of a large brain underpinned our stunning divergence from our primate ancestors. And we saw how meat powered the human brain to expand to 4X the size from that of our hominid ancestors.

In Section 2, we witnessed how the brain became our greatest weapon yet our biggest liability. It forced energy tradeoffs between tissues and organs, turned us into obligate meat-eaters, and re-shaped our entire bodies. Using mathematical relationships in biology, the ever-debated question, “What are humans designed to eat?” is unequivocally answered.

Here in Section 3, we dive into deeper questions.

• Why did nature select for big brains?
• Why aren’t elephants that have brains 3X bigger more intelligent?
• What makes humans “sapiens?”

Part I: Your Brain on Meat

• Brain Food – Intro
• Section 1: Your Brain on Meat
• Section 2: The Brain-Body Paradox
• Section 3: Meat the Brain that Became Sapiens (this post – below)
• Section 4: Evidence for a Meat-Based Diet

Part II: Your Brain on Plants (coming soon)

Part III: Brain – Body Connection (coming soon)

Meat the Brain that Became Sapiens

So far in this series I’ve argued that obtaining meat was the main selective pressure (due to climate change) for early humans. And obtaining it became the selective priority in which everything else fell in line.

I’ve argued that the main downstream trait that nature selected for was a big brain.

Countless other traits were selected for to improve meat capturing as we saw in The Brain-Body Paradox. But none were as important as the brain.

And the only way nature could select for our cerebral cortex was an energy dense diet. Meat allowed us to escape the energetic constraint that limits the number of cortical neurons that can be afforded by a raw plant-based diet in the wild. (r, r)

Every billion neurons requires 6 calories per day. Our growing brain was ever-more hungry, and meat was the only solution to keep it on its expanding trajectory.

Here I’m going to argue that this big brain (thanks to meat) is what allowed us to climb to the top of the food chain. It’s what made us sapiens.

But 1st we have to address the elephant.

The Elephant in the Room

Does size matter?

An elephant has a brain 3X as big as ours. If it was size that mattered, elephants would rule the lands.

However, equating a bigger brain to greater cognitive capabilities assumes that all brains are wired the same. But they aren’t.

Primates have a brain advantage over other mammals. They can pack more neurons into less space.

So the question becomes:

Rather than size, is it the total number of brain cells (neurons) that actually matters?

Neurons and Cognitive Ability

Does the total number of neurons account for the differences in cognitive abilities between animals?

I think it’s important to note, that cognitive differences between animals are a matter of degree. These differences are like a dial, not a light switch.

For example, chimps, our closest living relatives, can fashion tools to forage army ants, crows can craft twigs and use their own feathers to get to hard to reach food, while humans can make tools that make tools. (r, r)

While chimps and gorillas can’t talk like humans, they do communicate with sign language.

Elephants, considered among the most intelligent animals in the world with brains larger than any other land animal, have a degree of self-awareness, with the ability to recognize themselves in mirrors. (r) While humans have the ability to ponder their own existence.

But if we equate cognitive ability to total number of neurons we run into a problem.

The African elephant’s brain isn’t only 3X bigger than the human brain but it also has 3X as many neurons.

By this metric elephants should have humans in cages at the zoo.

So if it’s not size nor total number of neurons that matter, than what is it?

Location, Location, Location

Brain real estate is just as critical as housing real estate.

Location matters. A lot.

The prefrontal part of the cerebral cortex is thought to be the seat of higher cognition, the location that gives us abstract reasoning, intricate planning, and complex decision making.

The cerebellum, at the back of the brain, coordinates movement like walking and reflexes.

Together, the cerebral cortex and cerebellum account for the vast majority of neurons in the brain.

And although the African elephant has 3X as many neurons as a human, 98% of those neurons are located in the cerebellum.

Only 2% of the elephant’s neurons, 5-6 billion neurons, are located in the cerebral cortex, whereas humans pack 16+ billion neurons into a much smaller cerebral cortex. (r)

Humans thus have 3X the neurons in less than half the size of the cerebral cortex of the elephant.

This is to say – the human brain not only increased in size, it increased the number of brain cells by packing more neurons into less space (thanks to our specialized primate neurons), while also concentrating these neurons in the area of the brain that gives superior cognitive ability. (r)

No other animal has this combination.

1. Primate Brain = Ability to pack more neurons into smaller spaces
2. Meat = Allows the escape from the energetic constraint of a raw plant-based diet in the wild (that limits all other animals to the smaller number of cortical neurons)
3. Cerebral Cortex = Selective advantage to obtaining meat and thus survival

Humans surpass all other animals in the number of neurons in the cerebral cortex. Only made possible by a meat-based diet. (r)

Becoming Sapiens

“Ants and bees can also work together in huge numbers, but they do so in a very rigid manner and only with close relatives. Wolves and chimpanzees cooperate far more flexibly than ants, but they can do so only with small numbers of other individuals that they know intimately. Sapiens can cooperate in extremely flexible ways with countless numbers of strangers. That’s why Sapiens rule the world, whereas ants eat our leftovers and chimps are locked up in zoos and research laboratories.”

— Yuval Noah Harari, Sapiens

If Harari is right, and it seems he is, it’s our ability to cooperate in flexible ways in large numbers, facilitated by our unique brain, that led Sapiens to rule the world.

If we put the pieces together, we can see that the transition to an energy dense brain fuel, meat, allowed humans to amass a remarkable number of neurons. And nature preferentially selected prefrontal cortex growth for coordination, cooperation and communication.

So even though the growing brain was energy hungry (using up to 25% of all our energy) and the large head brought about severe childbirth risks leading to premature births, nature still selected for a big brain because of its unique powers.

Meat the Brain that became Sapiens: Brain Superpowers

As Harari details in his phenomenal bestseller, Sapiens, a growing prefrontal cortex enabled humans to cooperate in flexible ways, in large groups, with a versatile language.

Out of this big brain, a more nuanced and complex set of language(s) (that I call “Language 1.0” and “Language 2.0”) developed that allowed humans to develop abilities that cannot be found among any other species.

Language 1.0

The human brain was the force behind our ability to hunt mammoths 2X the size of an elephant. Without this big brain we couldn’t have created the axes and spears, we couldn’t have coordinated the attack. We couldn’t have done it alone. We did it as a team.

In addition to coordination, with complex language we could give detailed explanations of past events as well as preconceived future plans.

If a lion just made a kill, we could describe to our tribe how it’s too dangerous to venture into that area for the time being (past event), but after the den of lions leave, we can go pick up the scraps (future planning).

It’s this “Language 1.0” that transformed unskilled scavengers into hunters that gradually climbed up the food chain.

This climbing wasn’t a result of muscle, rather brain power that led to robust social structures, nuanced and detailed coordinating and communicating where we relied on each other and helped each other for the greater good of all.

No other animal does this like humans. And no other animal has a brain like the human brain.

Fire

It’s important to mention fire’s role in developing Language 1.0 and catapulting us to Language 2.0.

About a half of a million years ago, before homo sapiens, earlier human species domesticated fire.

With the ability to control fire we could eliminate parasites from food. We could keep warm in the cold climate. And we could use it for protection from predators and insects.

And though fire was neither sufficient nor necessary for human brain growth (as frequently hypothesized) it may have enabled a further shrinking of the intestinal tract, which feasibly could allow an even bigger brain. (r)

Beyond these advantages, perhaps fires biggest impact was its influence on social structure.

It’s thought that fire helped create a human social life from which pair bond relationships grew and wider social connections flourished. It helped launch Language 2.0.

Meat the Brain that Became Sapiens: Thinking about No-Thing

Language 2.0 – The Ultimate Superpower

Language 2.0 is more abstract than Language 1.0.

While Language 1.0 enabled us to communicate and coordinate complex events (both past and future), Language 2.0 allowed us to communicate about things that don’t exist.

We created stories, beliefs, and aims around intangibles.

We formed agreed upon imaginary ideas.

Myths, legends, and religions. Moral codes. Law.

Try and convince a gorilla that if he fasts on the sabbath he can win favor in the afterlife whereby it will rain infinite bananas. You can’t.

Rules and regulations are agreed upon imaginary concepts.

And it is because we have the ability to share in beliefs and ideas that we can cooperate together towards larger aims.

Shared imaginary concepts allow humans to scale.

It’s agreed upon ideas that can spread from an individual to families to communities to states to nations. It’s what got humans to the moon. And it’s how I can feel confident if I invest money today, I can see a return tomorrow. It’s why a legal contract carries any weight.

Shared trust in these abstractions allow me to exchange paper currency for a car, which I can drive on roads. Roads which I can place confidence that my 1-ton piece of metal on wheels won’t smash into your 1-ton car when my light is green and yours is red.

The importance of Language 2.0 is that human behavior became rooted in beliefs rather than environment.

If I submitted to the belief that eating animals is bad, I’ll forego eating them even if it costs me my health. Or if I choose to agree with others that bitcoin has value than it does to the extent that other people agree.

No other specie does this.

All other animal behavior is rooted in environment. Human behavior stems from beliefs.

Meat retreat; Brain retreat

About 12,000 years ago the weather warmed as cold climate withdrew from the last glacial maximum.

Accompanying the warm weather, plants flourished.

And with our remarkable brains – we invented agricuture.

We began to manipulate plants to increase food supply. A plant-based diet followed. Population exploded.

A population that saw health decline with each subsequent generation. We were eating a diet which, over the intervening millions of year, we had become ill-equipped to eat.

The damage was insidious. We didn’t see how becoming dependent on wheat robbed us of nutrition.

Yet today, 90% of our calories come from what our ancestors domesticated less than 10,000 years ago. Wheat, corn, rice – which now make up over 50% of all calories – were basically never eaten until this time. Now they are our daily staples.

Not only have our bodies become weak and ill since the agricultural revolution, but our brains have shrunk close to 10%.

For millions of years humans #1 survival priority was obtaining meat. To this end our bodies evolved and our brains grew. Then in the blink of an eye, we eschewed what nature selected.

To put this into perspective: If human evolution was a 100 meter dash, in less than the last step we changed our entire diet. In that stride our brains have dramatically shrunk and our health has deteriorated. And we are perplexed why.

We stopped eating brain food. (r)

Meat, Brain, Language, Sapiens

If we look across species we can see that elephants have their trunks, birds – wings, giraffes – long necks, and sapiens – brains.

A brain that gave the ability to do this:

This was made possible by Brain Food. Food we’ve since largely abandoned.