I’ve never understood why anyone would think a button that is nothing more than a bare rectangle around some text was intuitive.
Flat designs looked “cleaner” and more “modern” (Microsoft’s subsequent portmanteau term for its Metro design), but there was a price to pay.
The consequence is that users find navigation harder, and so spend more time on a page. Now research by the Nielsen Norman Group has measured by how much. The company wired up 71 users, and gave them nine sites to use, tracking their eye movement and recording the time spent on content.
“On average participants spent 22 per cent more time (i.e. slower task performance) looking at the pages with weak signifiers,” the firm notes. Why would that be? Users were looking for clues how to navigate.