Urban Life Versus Evolution

Two related articles caught my eye recently. Yesterday the BBC reported that light reflected off of city skyscrapers disrupts the behavior of animals and insects:

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Dr. Robertson said that water was the primary source of horizontal polarized light in the natural world, and that many animals-including birds, insects and reptiles-had highly developed polarization vision.This particular form of light played a key role in the animals' lifecycle, such as finding breeding and feeding sites, he added.A well documented example is the way that baby sea turtles rely on the direction of starlight and moonlight reflected off the water's surface in order to help them find the ocean when they emerged from their nests.Yet, there are examples of turtles in urbanised areas heading towards the brighter buildings and street lamps.And a few weeks ago the Boston Globe published a fascinating-and much linked to-article on the city's impact on our mental health called "How the City Hurts Your Brain":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. ...

Consider everything your brain has to keep track of as you walk down a busy thoroughfare like Newbury Street. There are the crowded sidewalks full of distracted pedestrians who have to be avoided; the hazardous crosswalks that require the brain to monitor the flow of traffic. (The brain is a wary machine, always looking out for potential threats.) There's the confusing urban grid, which forces people to think continually about where they're going and how to get there.The reason such seemingly trivial mental tasks leave us depleted is that they exploit one of the crucial weak spots of the brain. A city is so overstuffed with stimuli that we need to constantly redirect our attention so that we aren't distracted by irrelevant things, like a flashing neon sign or the cellphone conversation of a nearby passenger on the bus. This sort of controlled perception-we are telling the mind what to pay attention to-takes energy and effort. The mind is like a powerful supercomputer, but the act of paying attention consumes much of its processing power.Clearly cities are are more efficient than sparse, distributed communities. Keeping settlements dense cuts down on transportation costs for everything and capitalizes on economies of scale. But humans and other animals have brains and bodies that have been tweaked over eons of evolution to work especially well in open, natural spaces. We're horribly maladapted for the urban environments we've built. This a fundamental, long-term challenge for life on Earth.

It'll be many, many generations before humans, insects, and turtles adapt to the urban environment by natural selection. Perhaps in the meantime urban planners, architects, and policymakers should try to design cities that more closely resemble the environments animals are built for. Fixing the problem of polarized light mentioned in the BBC article would be as simple as using a different surface for skyscrapers. And if architects mastered ecology the way they do building codes, who knows what other ways they could make buildings mesh with the surrounding natural systems.

To deal with the psychological impact of city life on humans, of course, we'd need to really reinvent urban spaces. A proposed residential project by Massaud in Guadalajara, Mexico, called "Life Reef" (above) seems to be a step in the right direction. There's also the Atocha train station in Madrid (left), which features a kind of wild park inside. I'm sure this stuff is being discussed in studios at SciArc and Harvard's GSD, but I'm not sure evolutionary biology and psychology get much weight in the real world of city building yet.At some point (after we deal with the global economic crisis, maybe), we'll want to make cities that work not only economically, but ecologically and psychologically as well. We'll have to make the urban jungle more like the original jungle (or savannah).Images: Scyscraper by Flickr user petes travels; Hong Kong street by Flickr user M Y. Life Reef from Massaud; Atocha Station from Wikipedia.