When cooperation became intelligence

We may be describing the evolutionary story of human intelligence, and thus, of what we consider consciousness, the way minds meet the world, backwards

Seventy-four thousand years ago, the sky went dark. On the island of Sumatra, the supervolcano Toba erupted with a force that was beyond anything humans had previously known. The Earth’s atmosphere was filled with ash which blocked out the sun for years. Temperatures fell, and forests died. There had been no warning, and so there was no ability to plan for such a catastrophe. When animals disappeared and plants withered and died, food became harder to find. Genetic evidence suggests that human numbers fell to perhaps 3,000-10,000 breeding individuals.

The ability to understand others, communicate intentions, regulate fear, remember relationships and sustain trust created a social world in which there was value in a particular form of increasingly sophisticated cognition that facilitated cooperation. (AFP)

Catastrophes such as this create an unusual kind of evolutionary pressure. Under ordinary conditions, many traits can co-exist because the environment can accommodate them. But, when a population contracts sharply under severe environmental pressure, traits that determine survival can suddenly become much more important. My colleagues at Princeton, Peter and Rosemary Grant have reported seeing this happen in Darwin’s finches, a group of roughly 18 closely related bird species from the Galápagos archipelago and Cocos Island. When drought on the island of Daphne Major left only large, hard seeds for birds to feed on, the roughly 20% of birds with the deepest beaks that could crack the seeds survived. The rest died. When the population recovered, the next generation had larger beaks, and the drought revealed which existing variation mattered under the new conditions.

These capacities, such as sharing scarce food or communicating the location of food, are hard to see in the fossil record but they must have been important. A mother with an infant could no longer depend only on what she herself could gather, but her best bet would have been to rely on reciprocity to share what little resources they had. Although a bottleneck could not have created the capacity for sharing, it could have made their survival value much greater.

Along with sharing came the need to read other humans accurately. Our ancestors would have had to quickly assess who could be trusted to share knowledge or resources when there is not enough. We don’t generally think of these abilities as intelligence, but they may have been among the most consequential skills during times of crisis.

In fact, language itself may have been shaped by these needs to cooperate with others. Humans possessed substantial linguistic capacity well before the eruption — starting from the African Middle Stone Age — but a crisis like Toba would have made the cooperative value of language much greater. Simply knowing where water was available, or which plants were edible, would have been helpful. But, the ability to teach a child or others in the group which plants to avoid and where to find water would have been better from a survival standpoint. With language, an entire group could act on a memory that previously belonged to one individual. And in this sense, language allowed knowledge to become portable and move between minds and accumulate across generations.

This may help explain why human intelligence is so different from the intelligence of other animals. An octopus can learn to solve problems remarkably quickly, and also remember what it has learned, but much of this intelligence is directed toward navigating a physical environment. In order to survive, an octopus has to find food and escape predators. Humans also do these things, but our most consequential environment is social. Intelligence, in the context of humans, became larger than what is simply inside the human brain, and rather, became distributed across many.

This is why we may be describing the evolutionary story of human intelligence, and by extension, of what we consider consciousness, the way in which our minds meet the world, backwards. We tend to imagine that intelligence came first. Humans became clever, and their cleverness allowed them to cooperate. But cooperation may have been part of the environment in which our particular form of intelligence evolved. The ability to understand others, communicate intentions, regulate fear, remember relationships and sustain trust created a social world in which there was value in a particular form of increasingly sophisticated cognition that facilitated cooperation. And in the current time, when we think of human cognition — the broad set of mental activity that includes perception, attention, memory, judgment, and language — as being what artificial intelligence is performing better than us, it is worth remembering that our real skill was not these, but rather the instinct to cooperate that gave rise to these in the first place. That, rather than cognition, is really what makes us human.

Ramanan Laxminarayan is president, One Health Trust and author of the forthcoming book, Bacteria to Buddha: How Cooperation Shaped Consciousness – and Makes Us Human. The views expressed are personal

(This is a Hindustan Times digital exclusive)