Flat gray concrete lines the streets, while windows form repetitive glassy intervals in stark brick walls. With monotonous straight lines as far as the eye can see, there’s nowhere pleasant to rest your gaze. It may seem a superficial problem, but our research has found that looking at urban landscapes may actually give you a headache.
Over tens of thousands of years, the human brain evolved to effectively process scenes from the natural world. But the urban jungle poses a greater challenge for the brain, because of the repetitive patterns it contains. Mathematician Jean-Baptiste Joseph Fourier showed that we can think of scenes as being made up of striped patterns, of different sizes, orientations and positions, all added together. These patterns are called Fourier components.
In nature, as a general rule, components with low spatial frequency (large stripes) have a high contrast and components with high frequency (small stripes) have a lower contrast. We can call this simple relationship between spatial frequency and contrast a “rule of nature”. Put simply, scenes from nature have stripes that tend to cancel each other out, so that when added together no stripes appear in the image.