Hack 39. Avoid Holes in Attention

Our ability to notice things suffers in the half-second after we've just spotted something else.

A good way to think about attention is as the brain's way of paring down the sheer volume of sensory input into something more manageable. You can then concentrate your resources on what's important (or at least perceived to be so on first blush) and ignore the rest. If processing capacity weren't limited, perhaps we wouldn't need attention at all-we'd be able to give the same amount of concentration to everything in our immediate environment, simultaneously.

Another reason we continually pare down perception, using attention as a final limiting stage before reaching conscious awareness, could be that perception causes action. Maybe processing capacity doesn't intrinsically need to be limited, but our ability to act definitely is: we can do only one major task at a time. Attention might just be a natural part of conflict resolution over what to do next.

M.W.

Attention isn't the end of the chain, however. There's conscious awareness too. The difference between the two is subtle but important. Think of walking down a street and idly looking at the faces going by. Each face as it passes has a moment of your attention, but if you were asked how many brown-haired people you'd seen, you wouldn't have the slightest idea.

Say somebody you recognize passes. Suddenly this semiautomatic, mostly backgrounded looking-at-faces routine jumps to the foreground and pushes the face into conscious awareness. This is the act of noticing.

It turns out the act of noticing takes up resources in the brain too, just as paying attention does. Once you've noticed a face in the crowd, there's a gap where your ability to consciously notice another face is severely reduced. It's a big gap tooabout half a second. This phenomenon has been dubbed the attentional blink, drawing a parallel with the physical eye blink associated with visual surprise.

Attentionjust like vision, which cuts out during eye movements [Hack #17] is full of holes that, as a part of everyday life, we're built to ignore.

In Action

There's a standard experiment used to induce the attentional blink, using a technique called rapid serial visual presentation (RSVP). RSVP consists of projecting black letters onto a gray screen, one at a time, at about 10 letters a second.

You're instructed to watch the stream of letters and be on the lookout for two particular targets: a white letter and the letter X. Spotting either on its own is easy enough. One-tenth of a second (the length of time a letter is on-screen) is enough time for recognition and awareness. Spotting the targets when they're close together in time, however, is much harder.

If the letter X follows the white letter by five places or fewer, you'll probably miss it. Spotting the white letter, the first target, stops the second target, the X, from reaching conscious awareness. That's the attentional blink.

Obviously this isn't an easy test to do at home, but we can approximate it using speed-reading software. Speed-reading software often has a function to run through a text file, flashing the words up sequentiallyand that's what we'll use here.

You can use whichever software you like. I used AceReader Pro (http://www.stepware.com/acereader.html; $49.95; trial version available).

Although the AceReader Pro trial version is suitable for this small test, it is available only on Mac and Windows. FlashWare (http://www.flashreader.com) is a simple, freeware Java applet that takes a file as input for rapid serial visual presentation. GnomeRSVP (http://www.icebreaker.net/gnomersvp) and kRSVP (http://krsvp.sourceforge.net) are speed-reading applications for the Gnome and KDE Linux desktops, respectively.

Whichever piece of software you choose, you'll need it to have a mode that lets you load an arbitrary file and step through it at about 300-400 words a minute. For AceReader Pro, that means choosing the Online Reader & Expert Mode option.

You'll need a text file, preferably one you haven't read. Ask a friend to choose two relatively unusual words for you from a random place in the text, making sure they're only two or three words apart. These are the words you have to look out foryour targets.

Now load the text into the speed-reader software (in AceReader Pro, choose File Load File), set the words per minute (WPM) to 400, and click the Play button (the green triangle) to begin. What you're expecting to experience is that you'll spot the first word easily and miss the next one completely. Figure 3-7 shows AceReader Pro in action; you'd notice the first (left), but the second (right) would go utterly without notice.

Date: 2015-12-11; view: 696