Intuition and Usability

by Kevin Godby

Yesterday in class, the use of the word intuitive came up. In HCI, when people talk about an interface being intuitive, what they really mean is that it’s learnable—that is, the interface can be learned in a very short period of time. After that short learning period, the interface seems natural, easy to use, and so obvious. If this learning period is short enough (or not obvious), then we blithely claim that the interface is intuitive.

An example of an interface that can be learned quickly—so quickly that the learning period is often forgotten—is the multitouch gestures on the iPhone. It’s not natural to associate pinching your fingers together with zooming out. That’s not something that happens in our everyday lives. So why does this gesture seem to intuitive? Because Apple has spent millions of dollars on commercials and tradeshow demonstrations showing this gesture over and over again. Your friends show it to you when they’re trying to convince you to buy an iPhone. Steve Jobs shows you the pinching gesture when he’s introducing the iPhone. By the time you’ve bought an iPhone for yourself, you’re familiar with the simple gesture and it just seems intuitive.