The Social Leap

It’s six or seven million years ago and you’re a chimpanzee-like ape living in the lush rainforests of central Africa. Up in the forest canopy, food is plentiful, predators are rare, and life is easy. Unfortunately, all that is about to change.

Over the next million years, climate change and tectonic shifts will erode your verdant jungle habitat. While you get to live in the trees, your descendants will have to scrape by on the open grasslands of the savannah. Down there, there’s less to eat and a lot more hyenas and sabertooth tigers to watch out for. 

Life isn’t so easy anymore. If your species wants to endure, it will have to adopt a whole new set of survival strategies.

The key message here is: Conditions on the savannah forced our ancestors to evolve a more social lifestyle.

Our chimp-like ancestors most likely didn’t move to the savannah by choice. After all, compared to life in the trees, eking out an existence on the ground is much more difficult. For one, the vast, relatively sparse fields of the steppe meant pre-humans had to travel farther to gather food. Worse still, all that open space provided little protection from predators.

These new conditions put pressure on our ancestors. The only way to survive was to adapt. For instance, Australopithecus afarensis, a species of ape which emerged three million years ago, is notable for having developed narrower hips to aid bipedal walking, and for having more mobile shoulders and wrists to enable throwing. These changes made it possible to move more quickly and also to throw stones – a crucial skill for warding off large predators.

However, while one ape throwing stones is good, many apes throwing stones is even better. For this reason, the most important adaptation our ancestors evolved was the ability to work cooperatively. Just think, almost every survival strategy – from hunting and watching out for enemies to raising young – becomes much more effective when done in groups.

Of course, working together in an interdependent group isn’t easy. Effective coordination requires communication skills, emotional intelligence, and other new mental capacities we take for granted today. Thus, in order to survive, early hominids had to make a “social leap” by evolving bigger brains and honing their interpersonal abilities.

In the next blink, we’ll take a closer look at how our cognitive capacities grew from this evolutionary pressure.