The city has always been an engine of intellectual life, from the 18th-century coffeehouses of London, where citizens gathered to discuss chemistry and radical politics, to the Left Bank bars of modern Paris, where Pablo Picasso held forth on modern art. Without the metropolis, we might not have had the great art of Shakespeare or James Joyce; even Einstein was inspired by commuter trains.

And yet, city life isn’t easy. The same London cafes that stimulated Ben Franklin also helped spread cholera; Picasso eventually bought an estate in quiet Provence. While the modern city might be a haven for playwrights, poets, and physicists, it’s also a deeply unnatural and overwhelming place.

Now scientists have begun to examine how the city affects the brain, and the results are chastening. Just being in an urban environment, they have found, impairs our basic mental processes. After spending a few minutes on a crowded city street, the brain is less able to hold things in memory, and suffers from reduced self-control. While it’s long been recognized that city life is exhausting — that’s why Picasso left Paris — this new research suggests that cities actually dull our thinking, sometimes dramatically so…

This research arrives just as humans cross an important milestone: For the first time in history, the majority of people reside in cities. For a species that evolved to live in small, primate tribes on the African savannah, such a migration marks a dramatic shift. Instead of inhabiting wide-open spaces, we’re crowded into concrete jungles, surrounded by taxis, traffic, and millions of strangers. In recent years, it’s become clear that such unnatural surroundings have important implications for our mental and physical health, and can powerfully alter how we think.

Recent research by scientists at the Santa Fe Institute used a set of complex mathematical algorithms to demonstrate that the very same urban features that trigger lapses in attention and memory — the crowded streets, the crushing density of people — also correlate with measures of innovation, as strangers interact with one another in unpredictable ways. It is the “concentration of social interactions” that is largely responsible for urban creativity, according to the scientists. The density of 18th-century London may have triggered outbreaks of disease, but it also led to intellectual breakthroughs, just as the density of Cambridge — one of the densest cities in America — contributes to its success as a creative center. One corollary of this research is that less dense urban areas, like Phoenix, may, over time, generate less innovation.

The key, then, is to find ways to mitigate the psychological damage of the metropolis while still preserving its unique benefits.

I’ve become happiest living nearby a city. Our piece of a rural patch is consumed by owner-builders. Many of us earned a living on construction trades – and built studios for plastic arts, two and three-dimensional forms for humans to reflect in and upon.

I go to the city [town, really] for groceries and necessities. I go to the computer for information. I go for a walk with our dogs for exercise and relaxing my mind. Often setting my mind free at the same time.