Rounded rectangles are everywhere. You might think the reason they are so ubiquitous is because web and product designers’ minds are being controlled by an alien graphical design style ray that shows little chance of letting go. Or, maybe not. Beauty, in the case of the rounded rectangle, might be in the eye of the beholder – literally.
Apparently the visual system favors rectangles with rounded corners, making layouts, interfaces and presentation graphics easier to view and take in. Having a hard time believing that rounded corners make a difference, try this. Look at the images below. Which is easier to look at?
The reason the circle appears more agreeable is because we are wired to prefer round to sharp edges (and by extension round to sharp things). Keith Lang at UI&Us quotes researcher Jürg Nänni on the eye-brain’s peculiar penchant for roundness:
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. – Professor Jürg Nänni as quoted by Keith Lang (see below)
Anthony Tseng at UX Movement presents two other examples where rounded corners aid and abet the perception of graphical information. The box diagram is a common graphical type used in organization charts and process diagrams. Note the differences between the rectangular and rounded lines. The curves add flow to the procession through the diagram.
In a second example Anthony Tseng shows how rounded corners not only guide the eyes but also act on the attention of the viewer. In what might be a great tip for instructional designers and artists notice how the use of the corner radius acts to focus attention on what is inside the boxes.
Rounded corners also make effective content containers. This is because the rounded corners point inward towards the center of the rectangle. This puts the focus on the contents inside the rectangle. – Anthony Tseng at uxmovement.com
Still wondering why we see so many rounded rectangles in objects around us?
Tseng, Anthony, “Why Rounded Corners are Easier on the Eyes“
Lang, Keith, “Realizations of Rounded Rectangles“