We humans evolved over millions of years, via an almost unimaginably slow process. Anatomically modern humans have been around for roughly 300,000 years, and behaviorally modern humans (that is, humans who used language, rudimentary technology, symbolic ornamentation, etc.) came along about 40,000 years ago. Presumably our evolution continues even today, but given how slowly it goes, it feels safe to say that our species has been largely stable for the last several thousand years.
Natural selection teaches that through these eons of evolution, humans became better and better adapted to thrive – but it’s the world of many millennia ago that we adapted to. I hardly need to point out that our environment has changed drastically since then. Here’s a quick snapshot: 5000 years ago, earth had a human population of about 15 million people (that’s less than the current population of New York City), spread across six continents. Most lived in nomadic tribes or small villages, but the world’s first cities had recently arisen in Mesopotamia. The Bronze Age was just beginning. Swords and written language were exciting new inventions. The average human lifespan was under 30 years.
That is the world evolution shaped us for. When I try to wrap my head around what life was like back then, one detail that leaps out at me is the immediacy of it all. Which is to say, pretty much all the information a person might have absorbed then would have come from the immediate surroundings. Weather, the local animal life, the other people around them, the things they could see and touch; for a human of 5000 years ago, the immediate world was essentially all there was. Consequently, any piece of information coming in was personally relevant, and might well have had implications for one’s survival. (By “information,” I’m referring to all the data reported by the five senses, including data communicated from one person to another.)
All incoming information has to be processed by the central nervous system, which also mediates our responses to those stimuli. The human nervous system hasn’t changed significantly in the last 5000 years, but the world around us sure has. Nowadays we get information from all over the planet, very often in real time. Every moment we’re awake we are bombarded with all kinds of information: music trends, sports scores, political news, stock prices, movie plots, gossip, advertising, opinion pieces, the list goes on and on and on. And of course there’s still the immediate world of things we can see and touch, not to mention competing analyses of those phenomena, as well as forecasts of what our immediate world might bring us in the days, weeks, and months to come.
And yet, the central nervous system still tends to interpret all of that information as personally relevant and possibly survival-related. Because that’s what it evolved to do.
I think this evolutionary quirk of neurology is what accounts for the anxiety so many of us feel, so much of the time. When learning news of a tragedy thousands of miles away feels like a gut-punch, that’s not just a matter of emotional sympathy; on some visceral level, our brain doesn’t comprehend that this news isn’t about us and the people we know. When paying attention to the world feels overwhelming and exhausting, it’s because our central nervous system is constantly churning through more information than it’s really capable of processing, and everything somehow registers as personal. This could explain why so many people feel threatened by new ideas, or beliefs that differ from their own.
I expect this is also why unplugging yourself and spending time in nature can feel so calming. It’s why meditation – in which we try to still our minds, or focus on just one thought at a time – can be so grounding. And it’s why getting a massage can alleviate anxiety; when you lie on the table, eyes closed, the environment quiet and still, sensory receptors in your skin being stimulated in ways that you know are peaceful and safe, the entire world starts to feel like a better, more manageable place.