How do we perceive patterns in the shapes and colors around us, and why is it human nature to crave order—with a healthy dose of disorder—in our surroundings? Science writer Philip Ball has penned numerous books on the symbiotic relationship between the mind, the eye and the patterns in our built and natural world. Here, he explains how our minds recognize patterns and why we seek order amid chaos.

How many times does a motif have to repeat for the eye to recognize it as a pattern?

This is a fundamental question for science: How many times does something have to recur before we suspect that we’re seeing a law of nature and not just a coincidence? There’s no definitive answer to the question because it has to do with our intuition about what we see—the impression that there’s some order to the world around us. That intuition is so strong that we’re prone to seeing pattern even when there’s none. And we can discern genuine order even in shapes that have no repeating pattern at all, like a tree: It may look sort of random, but I suspect we sense the deeper regularity whereby the same basic form repeats at increasingly smaller scales as we go from trunk to branch tip.

What kind of behind-the-scenes mental gymnastics is the brain doing to help us understand what we’re seeing when we recognize a pattern?

When we see pretty much any scene—natural or otherwise—we’re getting an overwhelming amount of visual information. We need to make sense of this information in order to navigate our way around the world. So our minds unconsciously make a best guess. This means, for example, that we assume that there’s continuity even when we can’t actually see it—that the airplane that disappeared into a cloud is the same one that came out the other side, and that it traveled in a straight line in between. This sounds trivially obvious, but we have to do a lot of it—not least because our view of some objects is always partial, blocked by bits of others. Our brains very quickly learn rules for grouping objects together in our visual field. These rules were deduced in the early 20th century by a group of psychologists in Vienna who were called the Gestalt psychologists. They found that we group objects if they are the same shape, or the same color, or close together, or the same size. It’s in this way that we see a series of stripes, not just as “one stripe… and another one… uh, and another…” but as a “striped pattern.”

Is there an evolutionary benefit to simplifying the world around us?

These grouping mechanisms are just what the brain does—we don’t actually know if some of them are hardwired or learned. They are a best guess that allows us to make predictions about our environment and therefore they do have an evolutionary benefit. This is where our sense of pattern comes from, and it also partially explains why we find patterns pleasing: If there’s an adaptive advantage to being able to spot them, then it makes sense that we will have evolved a neural “reward system” that makes us feel good when we do. Exactly the same kind of thing happens, by the way, for sound input, and this is why we can make sense of the incredibly complex sound signal that is music, and why it gives us immense pleasure. Music is actually a very good analogy for vision in showing that we are inherently pattern-seeking creatures.

What about in our homes—is the human tendency to inflict order on our surroundings part of this need to group things by color and pattern?

Everyone has a different threshold for how much pattern and order they seek, as well as a somewhat different view of what counts as “order.” But these differences lie on a spectrum between simplicity—think minimalism— and complexity, which would be a polite way of describing my study. Somewhere on that spectrum each of us finds a compromise we can live with.

Does it calm the brain to surround ourselves with pared-down, predictable patterns? Or do we need some degree of disorder and discord, too?

We do seem to find comfort in regularity. But it’s worth noting that most patterns that we create or seek out aren’t the simplest possible, but usually a bit more complex. Think of wallpaper designs: They’re regular (they have to be, in order to be printed), but the patterned elements can be quite complex, not just squares or lines.

Hypothetically speaking, if our environments were totally minimized into white spaces and grids, would this be soothing for the brain or crazy-making?

It has generally been found that for all kinds of stimuli—including art and music, as well as in our homes—people tend to prefer some kind of compromise. This reflects a feature of the human brain: There’s an ideal level of stimulation that pleases us most. Too little and we’re bored; too much and we’re confused.