Our relationship with tools dates back millions of years, and anthropologists still debate whether it was the intelligence of human-apes that enabled them to create tools or the creation of tools that enabled them to become intelligent.
In any case, everyone agrees that after those first tools had been created, our ancestors’ intelligence coevolved with the tools. In the process our forebears’ jaws became weaker, their digestive systems slighter, and their brains heavier.
Chimpanzees, genetically close to us though they are, have bodies two to five times as strong as ours on a relative basis and brains about a quarter as big. In humans, energy that would have gone into other organs instead is used to run energy-hungry brains. And those brains, augmented by tools, more than make up for any diminishment in guts and muscle. Indeed, it’s been a great evolutionary trade‑off: There are 7 billion people but only a few hundred thousand chimpanzees.
In the distant past our tools improved slowly enough to allow our minds, our bodies, our family structures, and our political organizations to keep up. The earliest stone tools are about 2.6 million years old. As those and other tools became more refined and sophisticated, our bodies and minds changed to take advantage of their power. This adaptation was spread over more than a hundred thousand generations.