I've been having lots of conversations recently about the lack of affordance in touch interfaces. To some extent, this is simply because the visual language ha

I've been having lots of conversations recently about the lack of affordance in touch interfaces. To some extent, this is simply because the visual language hasn't developed yet - when you see something engraved on a 3d plinth in a desktop application, you know that it's a button that can be clicked. Touch interfaces haven't got to this level yet. Pretty much the only widely used affordance I can think of is a folded corner to show that you can swipe to turn the page, but even that is inconsistently applied. How do you know on an android contact that you can swipe sideways to SMS and the other direction to phone? Or even that swiping horizontally in either direction does anything at all? I could imagine some universally agreed way to indicate this, perhaps very subtle visual hints or gradients or a system where if you press and hold without moving you get a set of icon overlays that show you what you can do. There are a few different options, but to form a useful language they need to be widely adopted. One of the articles that triggered these conversations was "No to NoUI" http://www.elasticspace.com/2013/03/no-to-no-ui http://www.elasticspace.com/2013/03/no-to-no-ui which laments the modern tendency to hide interactions.