The human mind is unlike any other. It’s the key that unlocked language, culture, abstract reasoning, long-term planning, and large-scale political coordination — all the cognitive features that set us so far apart from the rest of the animal kingdom. It need not diminish other creatures’ intelligence to describe ourselves, in the words of British psychologist Cecilia Heyes, as “animals that specialize in thinking and knowing.”
Yet, in another sense, we aren’t so separate from the rest of nature. It’s not like our brains leapt fully formed into existence; we evolved, one small step after another, over millions of years. And now scientists can follow that trail backward to our ancient ancestors, shedding light on the process that culminated in the three pounds of world-dominating intellect we carry around upstairs.
There’s endless debate over what separates human cognition from that of other animals and when it emerged. Ideally, to answer ...
