What Does this Gorilla Have to Do with Usability?

from John Wooden, Director of Usability Services

on June 21, 2010

0 comments

In their well-known test of selective attention, psychologists Christopher Chabris and Daniel Simons asked test subjects to watch a short video in which two teams, one in black shirts, one in white shirts, move around and pass a basketball to one other. The subjects were asked to keep silent count of the number of passes made by the team wearing white.

About 25 seconds into the video, someone wearing a gorilla suit strolls into the middle of the passing game, beats their chest, and then strolls out again. The gorilla is on screen for nine seconds. The correct answer to the question about the number of passes is 15. But the real question was “did you see the gorilla?” About half of the test subjects did not.

Watch the video: http://www.theinvisiblegorilla.com/gorilla_experiment.html

In their new book, The Invisible Gorilla and Other Ways Our Intuitions Deceive Us, Chabris and Simon discuss the “illusion of attention” and our lack of awareness about the limitations of our perceptions, memories, abilities, and knowledge. (For example, more than 63% of Americans think they are more intelligent than the average American.) Their gorilla experiment demonstrates that when we focus our attention on one object or action, we can easily miss anything else going on around it. Other experiments found that people who missed seeing the gorilla had their eyes on it, but they didn’t see it because it was not what they were looking for.

Our tendency toward selective attention has implications for web interfaces. If you have ever participated as an observer of a usability test, you may have had the experience of watching a test participant fail to see what you perceive to be an obvious link, or button, or some other interface element. Seconds, or minutes, go by while the participant struggles, and you’re thinking, “Why in the name of all that’s good and decent can they not see that link? It’s RIGHT THERE! CLICK IT!!”

Users may miss a link or some other element for all kinds of reasons – lack of white space, crowding, small font, sub-optimal contrast – but one common reason is that the link (or button, or whatever) was like the gorilla in the experiment: users didn’t see it because it was not what they were looking for. In many instances, they were looking for other words – the words actually used didn’t match their expectations. They were looking closely for X and therefore didn’t see Y. So much of usability has to do with language, with using the keywords that match what your users have in mind. And even subtle differences can adversely affect a user’s ability to find what they are looking for.

Another common reason why users miss seeing what might seem blindingly obvious to a development team is that usage convention has led the user to expect one interface element when another has been used instead, such as a link instead of a command button.

Convention also leads us to expect certain elements in particular places – primary navigation at the top or on the left, a search box in the upper right, contact information in the footer, ads or other "fluff" on the right, and so on. If a user misses an interface element, it may be because it was not in the position they expected it to be, and therefore they simply didn’t see it.

One of the great benefits of usability testing is that it helps us to understand what users were actually looking for and what they expected – where was their selective attention focused? This in turn can help us design more effectively.

What do you think? Are there other implications for selective attention?

Comments

Add Comment