Considering Perception in User Interface Design

I read a couple of articles recently that reminded me of a user interface design discussion I once had with a friend of mine. First, let’s discuss the articles. The first, New Record for Human Brain: Fastest Time to See an Image, says that humans can actually see something in as little as 13 ms. That short time frame provides the information the brain needs to target a point of visual focus. This article leads into the second, ‘Sixth Sense’ Can Be Explained by Science. In this case, the author explains how the sixth sense that many people relate as being supernatural in origin is actually explainable through scientific means. The brain detects a change—probably as a result of that 13 ms view—and informs the rest of the mind about it. However, the change hasn’t been targeted for closer inspection, so the viewer can’t articulate the change. In short, you know the change is there, but you can’t say what has actually changed.

So, you might wonder what this has to do with site design. It turns out that you can use these facts to help focus user attention on specific locations on your site. Now, I’m not talking here about the use of subliminal perception, which is clearly illegal in many locations. Rather, it’s possible to do as a friend suggested in designing a site and change a small, but noticeable, element each time a page is reloaded. Of course, you need not reload the entire page. Technologies such as Asynchronous JavaScript And XML (AJAX) make it possible to reload just a single element as needed. (Of course, changing a single element in a desktop application is incredibly easy because nothing special is needed to do it.) The point of making this change is to cause the viewer to look harder at the element you most want them to focus on. It’s just another method for ensuring that the right area of a page or other user interface element gets viewed.

However, the articles also make for interesting thoughts about the whole issue of user interface design. Presentation is an important part of design. Your application must use good design principles to attract attention. However, these articles also present the idea of time as a factor in designing the user interface. For example, the order in which application elements load is important because the brain can perceive the difference. You might not consciously register that element A loaded some number of milliseconds sooner than element B, but subconsciously, element A attracts more attention because it registered first and your brain targeted it first.

As science continues to probe the depths of perception, it helps developers come up with more effective ways in which to present information in a way that enhances the user experience and the benefit of any given application to the user. However, in order to make any user interface change effective, you must apply it consistently across the entire application and ensure that the technique isn’t used to an extreme. Choosing just one element per display (whether a page, window, or dialog box) to change is important. Otherwise, the effectiveness of the technique is diluted and the user might not notice it at all.

What is your take on the use of perception as a means of controlling the user interface? Do you feel that subtle techniques like the ones described in this post are helpful? Let me know your thoughts at John@JohnMuellerBooks.com.