Centuries ago, our hominin ancestors — apes that have been linked to all modern humans via mitochondrial DNA evidence — began a great migration across the African continent, first originating in the deserts before the land became too harsh to support life. According to some recent studies, apes like orangutans and chimpanzees have demonstrated the ability to make plans, particularly migratory journeys in which they must plan for the future, suggesting a common learned memory that may have passed along the species millions of years ago. They display what has long been thought a uniquely human trait.
Among the new evidence that supports the migratory routes of our ancestors across the Sahara are the remains of the Irharhar River to the west, which, according to topography maps analyzing the summers just before the Ice Age 100,000 years ago, had the unusual property of flowing from south to north, providing humid corridors and leading our ancestors to an abundance of food and verdant ground; lush forests that would have sheltered them from predators during their travels.
When seasons changed, the river dwellers moved from place to place — think of it as prehistoric beach property, highly valued depending on the time of year. As they moved, they developed the ability to manipulate the land to create tools, tokens left in the modern-day Olduvai Gorge. As they migrated, they endured, and their brains changed, allowing them to develop the two traits necessary to plan for the future: self-control and mental time travel — the ability to do at least some degree of abstract thinking by anticipating how much time the journey will take; features that are exclusive to only large-brained animals. It need not be just a trek to uncharted lands — simply anticipating what you’ll have for breakfast tomorrow is in itself an example of mental time travel.
Chimps in the wild have also been known to carry small tools to nut-cracking sites — evidence that they plan their activity in advance and show up prepared. Episodic memory must play a role, too — the same function that allows us to remember our own childhoods; specific points in time recalled with the help of the medial temporal lobe. Long after our ancestors braved deserts and floods, we use the same techniques to recall our favorite fishing spots.
This behavior is not only limited to living out on the dangerous plain, as the chimp Santino at Sweden’s Furuvik Zoo demonstrated in 2013. When the zookeepers brought Santino out to his daytime enclosure, he became belligerent with the visitors who came too close to the fence. He searched the boundaries of the paddock and began to stockpile decorative stones off the ground before the zookeepers came to bring him back to his nighttime enclosure. The next day, he turned to his stockpile and hurled the collection of stones at his visitors, using this ferocious display to defend his territory.
Fortunately, the zoo moved Santino to a new fenced-in enclosure before anyone was physically harmed, and he no longer showed signs of aggression. These instances of planning need not happen in isolation, however. Rather, they benefit from collective actions and input taken by a group. Apes such as the wild orangutan Arno have been known to actively plan their travels with other members of the pride — as though mapping out the direction and distance of their destination.
The University of Indonesia recently published a study that followed Arno and 15 other male orangutans, concerning themselves with the loud echoing calls that the animals made back and forth to their families at night. The resonance of these calls was particularly important, as they indicated times of day for travel and when the trek was most preferable. These would be repeated until the orangutans changed calls, indicating a change in their plans of direction, and the calls grew louder — an indication to Arno’s rivals to stay away from his family.
Think of it as the world’s oldest platform of social media — original posts talking about your vacation, with a series of other distinct calls for status “likes.” Twelve hours later, the orangutans would be making similar calls, indicating the directions in which they traveled — suggesting that the researchers completed one of the first successful studies of long-term planning in primates.
Why did the orangutans do this? The researchers who tracked Arno suggested the environmental cues that simpler animals use to migrate may have played a part, alongside associative learning — understanding the association between a behavior and a stimulus. Simple exploration of a given territory would also yield different results at specific times — such as insects or flowers ideal for collecting and eating — and over time Arno and his friends would observe consistent patterns to base their plans around. Planning would also be ideal for the survival of animals, and would therefore be favorable to natural selection. This interaction would also create an environment in which animals would work collectively toward their own survival.
As we began to develop simple tools, our brains changed further. A 2013 study conducted by the University of California, Berkeley, on the craft of flint-knapping made another surprising revelation: our toolmaking abilities — simple tasks such as chiseling stones into wedges may have given birth to language itself. Learning language even in contemporary times has shown to significantly increase the size of the brain with stimulated activity in the hippocampus and motor cortex — a crucial point in our own development as infants, when we learn to process the meaning of words and the voices of those who speak them. It’s integral to the brain’s ability to form connections — not being exposed to spoken words early enough could permanently impair one’s ability to speak.
According to Thomas Morgan, one of the lead authors of the study and postdoctoral researcher in psychology at UC Berkeley, “Our findings suggest that stone tools weren’t just a product of human evolution, but actually drove it as well, creating the evolutionary advantage necessary for the development of modern human communication and teaching.”
The study suggests that much earlier than previously thought, we moved from making simple directional calls to using actual words in order to create crude stone knives as a group. In fact, the first phrase ever spoken in any language may have been words to the effect of “You’re doing it wrong,” or “Pass me that large rock.” Morgan’s study included more than 180 college students who were then broken up into “chains” consisting of five to 10 members each. The leaders of these chains were given a demonstration on how to break large pieces of an obsidian (a volcanic glass) into flakes.
Following the demonstration, they would show the piece to the next person in their chain, who then worked and taught the next person down the line. As the students worked, it soon became clear that verbal cues were the most effective way for the group to communicate what they learned, rather than through any physical demonstration alone. Not only did words provide precise details on what they did wrong, but speaking was also a way for them to engage with their teachers effectively. Stone flakes were used for about 700,000 years, but afterward technology began to move much more quickly with the advent of axes and knives carved from stone — suggesting a move from simple grunts for “Yes” and “No” to eventual words and phrases that could be easily remembered by the group.
The collection continued to grow as we built bigger and better things, transforming the land around us into cities. We think of the migration from the veldtland of Africa as an ancient and forgotten journey, rather than a continuous one. I like to recall a scene from my favorite film, “2001: A Space Odyssey” by Stanley Kubrick, when the furry hominin who has learned to use a bone as a weapon triumphantly tosses it into the air, and in that instance the tool dissolves into a vast, white space station. He doesn’t know it yet, but his descendants are hardly bound to this Earth — one day they’ll be stepping onto new worlds.
Nearly half a century ago, it was the moon. Now we dream of reaching Mars in another two decades. The obstacles are many. A great concern is whether people are psychologically prepared for prolonged periods of space travel — particularly on journeys that could take two to three years in isolation. The Mars500 mission studied some of these potential problems — a six-man Russian-European crew showed changes in perception of time and more reluctance to share negative feelings with the group. Technology is not quite there yet either — as communications systems back to Earth would be delayed up to 44 minutes. As technology continues to advance, however, so does the ever-growing field of neuroscience, and with it the power of human creativity. As distant as it may seem, the answer lies within our own brains, waiting to be unlocked.