They say that good design goes unnoticed. It puts the focus on the content and doesn’t offend you. Colours are an obvious way to achieve this. Brighter and contrasting colours will jump out at you, whereas a softer palette is easier on the eyes. Have you ever considered that the same can be said for shapes? Objects with sharp corners stick out more than those with rounded corners. It’s difficult to think of rounded corners as a trend, as they’ve essentially become an industry standard. We see them in hardware, in user interfaces and on the web. Rounded corners are here to stay, and it’s not just because they’re pretty. There’s more to them than meets the eye. Why, then, do we love rounded corners?
Rounded Corners are Easy on the Eyes (and the Brain)
It takes less cognitive load to see rounded rectangles than it does to see sharp-cornered ones. Professor Jürg Nänni, authority on visual cognition, states that:
A rectangle with sharp edges takes indeed a little bit more cognitive visible effort than for example an ellipse of the same size. Our ‘fovea-eye’ is even faster in recording a circle. Edges involve additional neuronal image tools. The process is therefore slowed down.
Sharp corners interrupt thought. To visualize a sharp-cornered shape, the brain processes point A to point B, pauses for a bit and then goes from point B to C, and so forth until it completes the circuit. In the case of a rectangle, it takes your brain 4 computations to recognize it. With rounded corners, the abrupt pause never happens, and your brain only does one single computation as your eyes smoothly scan its edges.
Which one is easier on the eyes?
We’ve Been Trained to Trust Rounded Corners
The year was 1981, and Macintosh was still in early development. Resident graphics master Bill Atkinson had just managed to get its OS to draw circles and ellipses, and he was proud of it. However, Steve Jobs, The Father of the Macintosh, had another more pressing request: rounded rectangles.
To Jobs, rounded rectangles were friendly, and he insisted that rounded corners were already everywhere. Jobs took Atkinson for walk to show that his request was not mere aesthetic whim. A few rounded objects and a “No Parking” sign later, Atkinson was convinced.
Atkinson managed to develop the necessary code to render rounded rectangles at lightning-fast speeds. Buttons and windows became rounded. These helped define the “safe” interface of the Macintosh. To customers, Mac had a softer, more welcoming appeal, which sat in contrast to the intimidating aura of both IBM and Microsoft’s products.
Apple’s legacy with rounded corners extends beyond software. When introduced, the iPhone was more “pocketable” than other phones of its time. Similarly, the iMac wasn’t as intimidating as the standard “Personal Computer” of the day: the Mac seemed like a laid-back friend; the PC, a man in a dark suit.
Jobs got it. Apple gets it. We are hard-wired to avoid and dislike sharp objects.
Which one would you let your 4-year-old touch?
Sharp corners say, “Go away”, “Don’t touch me” or “I’ll scratch you”; rounded corners say, “It’s okay to hold me”. As children, we were trained to stay away from knives and sharp objects because they can hurt us.
Neuroscientists call our aversion to sharp corners “avoidance response” or “contour bias”. We tend to develop negative bias toward a visual object based on its semantic meaning (e.g. “used for cutting”) and the emotions it triggers (e.g. threat, pain, fear). Our modern brains are thousands of years old, but we still haven’t outgrown this primordial reaction.
Rounded Corners and When to Use Them
Oversaturating your design with rounded corners isn’t a good idea, unless you’re designing for a very young demographic. When to use rounded corners depends on the emotions that you want your users to experience and the identity you wish to present.
Rounded corners evoke warmth and trust. Many call them “friendly rectangles” for this reason. This is exactly why many call-to-action buttons (a.k.a. buy-now or sign-up buttons) are designed this way. It makes customers feel safe about doing business with a brand.
Rounded corners are more effective for maps and diagrams, rendering them easier to follow. As mentioned earlier, the natural movement of our eyes is accustomed to curves. Sharp corners abruptly knock your attention off a path when it changes direction.