Chimps, our closest living cousins, have human-like brains … However, they don’t have social reality. When chimps select a leader, they don’t vote by making marks on smushed bits of dead trees like we do.
Humans are the only animals who can simply make things up, agree on them as a group, and they become real.
Most of your life takes place in a made-up world. You live in a country whose name and whose borders were made up by people. You allow particular humans to be leaders of that country, such as a president or a member of Congress, by following procedures invented by people long dead, such as elections, and you give them powers that were also made up by people.
You acquire food and other goods with something called “money,” which is represented by pieces of paper and metal and even by electromagnetic waves flowing through the air, and which is also completely made up. You actively and willingly participate in this made-up world every day. It is real to you. It’s as real as your own name, which, by the way, was also made up by people.
We all live in a world of social reality that exists only inside our collective human brains. Nothing in physics or chemistry determines that you’re leaving the United States and entering Canada, or that an expanse of water has certain fishing rights, or that a specific arc of the Earth’s orbit around the sun is called January. These things are real to us anyway. Socially real.
The Earth itself, with its rocks and trees and deserts and oceans, is physical reality. Social reality means that we impose new functions on physical things, collectively. We agree, for example, that a particular chunk of Earth is the United States and its carved up into 50 made-up areas called states. And sometimes we disagree. In the Middle East, for example, people kill each other over whether a parcel of land is Israel or Palestine. Even if we don’t explicitly discuss social reality, our actions make it real.
Humans are the only animals on this planet who can simply make things up, agree on them as a group, and they become real. Scientists don’t know for sure how our brains developed the capacity for social reality, but we suspect it has something to do with a suite of abilities that I’ll call the Five Cs: creativity, communication, copying, cooperation, and compression.
First, we need a brain that’s creative. The same creativity that permits us to make art and music also lets us draw a line in the dirt and call it the border of a country. This act requires us to invent some social reality (namely, countries) and impose new functions on an area of land, like citizenship and immigration, that don’t exist in the physical world. Think about that the next time you pass through Customs, or even when you leave one town and enter another.
Next, we need a brain that can communicate efficiently with other brains in order to share ideas, such as the idea of a country and its borders. Efficient communication for us usually includes language. For example, when I tell you that I’m running for office, I don’t have to explain that I’m talking about politics, not exercise, and that I plan to send flyers to voters, make speeches, demolish my opponents in debate, and so forth. My brain conjures these features and so does yours, allowing us to communicate efficiently.
Even if we don’t explicitly discuss social reality, our actions make it real.
We also need brains that learn by reliably copying one another in order to establish laws and norms to live in harmony. We teach these norms to our children and to newcomers, not only to smooth day-to-day interactions but also to help the newcomers survive. Anthropologist Joseph Henrich, in his book “The Secret of Our Success,” describes explorers in the 1800s who ventured into inhospitable, uncharted parts of the world, where many of them died. The expeditions that survived were the ones whose members became acquainted with the Indigenous people in those regions; they taught the explorers what to eat, how to prepare the food, what to wear, and other secrets of survival in the unfamiliar climate. If all individual humans had to figure out everything themselves without copying, our species would be extinct.
We need brains that cooperate on a vast geographical scale. Even the most mundane act, like casting a vote, is possible only because of other humans. Every mail-in ballot was designed and printed by other humans, on paper that was manufactured by other humans, from trees that were cut down by other humans; and when you drop it in the mailbox (constructed from steel by other humans), it’s delivered by other humans and counted by still other humans. Thanks to a shared social reality, all these thousands of people were in the right place at the right time doing the right things for you to participate in the democratic process.
Creativity, communication, copying, and cooperation — four of the five Cs — arose with genetic changes that gave our species a big, complex brain. (These terms are inspired by the evolutionary biologist Kevin Laland’s book, “Darwin’s Unfinished Symphony.”) But to make and maintain social reality, you also need the fifth C, compression, an intricate ability that humans have to a degree not found in any other animal brain. I’ll explain compression first by analogy.
Imagine that you are a police detective investigating a crime by interviewing witnesses. You hear one witness’s story, then another’s, and so on, until you’ve interviewed 20 witnesses. Some of the stories have similarities — the same people involved or the same crime location. Some stories also have differences — who was at fault or what color the getaway car was. From this collection of stories, you can trim down the repetitive parts to create a summary of how the events might have occurred. Later, when the police chief asks you what happened, you can relay that summary efficiently.
A similar thing transpires among neurons in your brain. You might have a single, large neuron (the detective) receiving signals from umpteen little neurons at once (the witnesses) which are firing at various rates. The large neuron doesn’t represent all of the signals from the smaller neurons. It summarizes them, or compresses them, by reducing redundancy. After compression, the large neuron can efficiently pass that summary to other neurons.