Robert Sapolsky in Nautilus:
The other day I fixed something—a rarity for me. The flotation device in the toilet water tank was rubbing against the side, getting stuck halfway up so that the tank didn’t fill completely. I own a hammer and know how to operate it. But I couldn’t fit it into the tank to whack the device back into place. Ditto for owning and using a wrench. It wouldn’t fit either. But fortunately I also own a plunger and I used its handle to push the floating thing back the other way, using the side of the tank as a fulcrum. It worked, although the device got bent so that the top of the tank didn’t quite fit. That overwhelmed me, so I called it a good day’s work. I was proud of myself. “There,” I thought smugly. “It’s not just chimps who can use tools.”
Humans used to be unique in lots of ways. We were the only species who made tools, murdered each other, passed on culture. And each of those supposed defining features has now been demonstrated in other species. We’re not so special after all. But there are still ways that humans appear to stand alone. One of those is hugely important: the human capacity to think symbolically. Metaphors, similes, parables, figures of speech—they exert enormous power over us. We kill for symbols, die for them. Yet symbols generate one of the most magnificent human inventions: art.
In recent years scientists from leading universities, including UCLA, University College London, and Yale, have made remarkable insights into the neurobiology of symbols. A major finding from their work is that the brain is not very good at distinguishing between the metaphorical and literal. In fact, as scientists have shown us, symbols and metaphors, and the morality they engender, are the product of clunky processes in our brains. Symbols serve as a simplifying stand-in for something complex. (A rectangle of cloth with stars and stripes represents all of American history and values.) And this is very useful.
More here.