Rounded corners in UI and web design have been a subject of much argument in the design community. It’s refreshing to see some research supporting their use to reduce cognitive load. The following quote is from the article Why Rounded Corners are Easier on the Eyes posted at UX Movement.
Some experts say that rectangles with rounded corners are easier on the eyes than a rectangle with sharp edges because they take less cognitive effort to visually process. The fovea is fastest at processing circles. Processing edges involve more “neuronal image tools” in the brain [1]. Thus, rectangles with rounded corners are easier process because they look closer to a circle than a regular rectangle.
