We still own the insecurities of a mid-placed creature in the food chain.
Going forward with “Sapiens. A Brief History of Humankind”, the book of Yuval Noah Harari. The first big idea was related to our exponential fast move on the food chain, now the link is created with our brain design.
There are two generic theories that describe the brain functionality. The first is the motivational theory. The second one is the scarcity theory, which gets more adopters. Is related to necessity to limit the brain energy drain, related to the disproportional large depletion versus its size (2-3 percent of the body weight accounts for 20% of the energy consumption at rest). By comparison, an ape brain require just 8%. The human brain is more thirsty than any other organ.
This is how learning is explained, but also how shortcuts and cognitive biases appeared, through the historically difficulty to ensure the carbohydrates and the precious glucose to fuel all the brain cylinders. If you like, shortcuts acts like a coasting function on an automatic gear shift box. This was valid in the period when we had to catch our lunch, and no fast-food was opened around.
Yuval subscribes to the scarcity theory and does it elegantly, linking it with the humans premature birth (a side effect of biped walk), which further alimented our insecurities.
Adding on that, we had a geometrical development, starting as a mid-placed creature in the food chain for millions of years, but leveraging our brain unique advantage, humans reached the top of the food chain 100,000 years ago. At the scale of evolution is a blink of an eye, and the ecosystem and even our reptilian deep brain couldn’t adapt to our new position.
Our rapid evolution left us with fears, tensions, anxieties. This makes us overcompensate by being aggressive and cruel.
Yuval Noah Harari: “Sapiens” review, part 2:
Homo Sapiens means wise man. The intelligent design was our principle of life.
With humble beginnings, homo sapiens is part of the family of apes. More than 6 million years ago, a female had 2 daughters. One will become a chimpanzee, other in time will become Sapiens.
We had three siblings: Homo Rudolfensis, Erectus and Neanthertalensis. Other close fellows: Homo Florensis (which was found in Indonesia, having just 1 m height) and Homo Ergaster.
High brain energy consumption:
Human have exceptionally large brain compared with the body volume. Their massive brain drains out power; 2-3 percent of body weight requires 20 percent of the energy consumption, when body is at rest. By comparison, brain of other apes require just 8 percent. Implications:
- We were forced to spent more time gathering food
- In time, muscles atrophied, Humans diverted energy from muscles to neurons
- For 2 million years, neural networks grew, but paid off just recently, humans increasing exponentially just in the last thousands of years (less than 1% of the time)
Figure 1: Human Brain Complexity at fMRI.
The biped walk took a toll on berth evolution:
Standing up on 2 legs freed up hands, which started to do much more many things. But homo sapiens pelvis narrowed, and that affected the way we give berth. Because of the biped position, morphology changed and humans are born earlier than they should be.
The pelvis in (L to R) modern human (Homo sapiens), early hominins and chimpanzee (Pan troglodytes). (Source: Laura Tobias Gruss and Daniel Schmitt, The evolution of human pelvis, US National Library of Medicine, March, 2015)
Human are born prematurely, earlier, when early vital functions underperform. That’s why it takes a tribe to rise a human.
There are some clear benefits: being linked with the mother build social skills, which would be used later; and because we are born underperforming, we can be educated and humans gained more spectrum.
Insecurities and risk aversion.
But being born underperforming, bring also a lot of psychological problems in time, related to our natural insecurity and risk aversion.
Upon that, we should add our median position in the food chain, for the most years of our evolution.
For hundreds of thousands of years we found our initial niche, as a woodpecker, using rocks to crack open bones marrow. This middle positioned us in the food chain, for million of years. Just 400,000 years ago, humans started to hunt large games.
300,000 years ago we had a major breakthrough: domestication of fire, bringing warm, light, weapons, cooking. Cooking killed parasites and made available new food like rice or wheat. Faster meals, healthier, helped minimize intestines and powered faster brain growth. Fire gave a disproportionate advantage, versus any other creature, and 100,000 years ago, Sapiens moved to top of food chain.
We had a geometrical advance that ecosystem couldn’t adapt. And our reptilian brain couldn’t too. Rapid evolution left us with fears and tensions, anxieties. This makes us overcompensate by being aggressive, dangerous and cruel.
Sapiens left Africa 100,000 years ago and tolerance is not a Sapiens trademark.
Soon, our sibling disappeared (Neanderthals, Denisova). We keep 1% to 4% of genome of the humans in Europe and middle east is Neanderthal, while 6% is Denisova in Malay.
Sapiens were more proficient hunters do to better technology and had better social skills, which led to multiplication and spread. Plus a new type of language. Sapiens were the last one left. Neanderthals disappeared 30,000 years ago, Flores dwarfed 12,000 years ago.
Next Big Ideas:
- Humans conquered the planet based on social skills and cooperation
- One of the key powers of Humans, was the ability of being united by sharing a common belief. A belief in Gods, in Order and Laws, in Money or in an Ideal.