From the January 2008 issue of Wired

FOUND: Artifacts of the Future

Or, as I would subtitle it: “A Human Factors Nightmare.”

All kidding and craziness aside, heads-up displays are coming into cars very quickly. Right now, they only display speed. The goal is to put information right in the driver’s field of view to minimize eye movements away from the road, similar to the Honda Civic dashboard. This makes sense from a cognitive perspective, except for one major flaw: people can only pay attention to one depth at a time. Therefore, attention must shifted from the road (relatively far away) to the windshield (much closer) in order to glean necessary information. That still leads to performance problems. What some systems are trying to do is to project the information “into the world” so that the speedometer is still on the windshield but appears on the road, so you don’t have to shift attention in depth. Smart.

Of course, while it’s easy to argue that the dashboard is way too cluttered to make driving safe, complex GPS systems are already part of high-end cars. They can be complicated to use and certainly provide a distraction if they make a mistake. Presumably, you’re driving in unfamiliar territory, and your map breaks, forcing you to fiddle with it?

There is a point of balance, where more information helps the driver drive better or multitask. But this makes human factors research all the more critical to ensure safety at all costs while not making driving an unbearable task.

GUI Wars: Web Browser Find Functions: Safari vs. Firefox

This is a great example of using attention research in user interface design. Standard Find functions in programs like Microsoft Word pop up a dialog box. You type what you want to find, then it highlights the word. It’s hard to find that highlighted word a lot of the time.

Firefox improves the search process by making the search box a bar that is part of the main window. Research has shown that attention often is distributed across discrete objects, and switching between objects incurs a cost (Egly, Driver & Rafal, 1994). With this layout, you don’t need to shift your attention between objects (though the search bar is all the way at the bottom):

The highlighted word is not that hard to find, but depending on where the word is, it can be difficult to do. In this case, you don’t incur an attentional shift cost from the Find window to the main browser window, but you do have to engage in costly visual search for the highlight word! Problematic.

The new version of Safari, however, fixes this incredibly well. It has the search bar right at the top, but it dims the entire page that’s not your search term and pops up and highlights in a bright yellow your search term. Luminance, motion, and color uniqueness. Talk about attention capture (Yantis & Jonides, 1984)!:

Making the Find tool part of the main window: excellent. Using animation to induce motion, brightness, and color uniqueness so that you can easily find what you were searching for? Genius.

GUI Wars: Window switching: OS X vs. Vista

Most computer users have a lot of windows open at once - web browser, e-mail, Word, Excel, etc. etc. Switching between them could always be accomplished through a variety of methods, but the latest operating systems have tried to jazz that up. Since a year or two ago, Apple’s OS X has had a feature called Expose. You press a mouse button or function key, and all the windows shrink to give you a live preview of each one. Then, you click on the one you want:

This works nicely because it gives you a bird’s eye view of all your windows. You can navigate this screen with your mouse or with arrow keys, so you can stay mouse- or keyboard-consistent.

Doing this in Windows Vista, the newest version of Microsoft’s dominant operating system, looks like this:

Pressing Alt-Tab brings this up, and multiple presses of Tab cycle through all the windows. This is nice because you can flip through your stack of windows until you find the one you want. In fact, the feature is called Flip3D.

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So the question is: which one is better? To answer that, we need to delve into the visual search literature. Visual search is a task used over and over again in attention research. You’re looking for a target amongst many distractors. What’s the best strategy you can employ to find it? Well, it depends on the properties of the targets and distractors. If your target is highly salient (i.e., unique compared to all the other items), search can be fast when you’re presented with all of the items at once. This is known as parallel search, and it’s fast no matter how many items are on the screen (find the green square):

However, if your target isn’t salient, then you’re slower. You generally have to examine each item individually until you find your target. This is known as serial search (find the green square again):

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So back to the window switching interfaces in both operating systems. How often is the window you want salient? Not that often - it’s not like the window that you want is bright green and everything else is gray. But you do have expectations sometimes. “I’m looking for iTunes, so I expect the window to look a certain way.” So you may be able to perform parallel search and get your search done faster. Not always, but sometimes.

Think about how both interfaces work - which interface allows you to perform parallel search? Expose! Because Flip 3D does not present you with all targets at once, there is no way you can perform quicker parallel search. You must perform serial search each and every time you switch windows. Considering how much people multitask, this can add up to a meaningful amount of time quickly.

There is the issue of clutter, though. More clutter in a display means longer searches. Expose definitely leads to more clutter than Flip3D, so a search in Expose may take longer. This primarily occurs is you have many windows open. Flip3D is not as cluttered because it only presents you with one window at a time, which underestimates how many separate objects we can handle at a time.

All in all? When it comes to switching windows, OS X’s Expose has the science behind it. By allowing users to engage in parallel search for their window, multitasking can be done much more efficiently than Vista’s Flip3D.