 |
| Photograph from Stock4b/Nonstock. |
Yogi Berra once said, "You can observe a lot just by watching." Or maybe it was "You can hear a lot just by listening." I don't remember precisely, because when Yogi's quip came out of my clock radio, I was madly looking for my car keys (which were in my hand the whole time). So what makes Yogi's aphorism—whatever it was—so maddeningly true? How can we look directly at things and not see them? The answer is that your brain perceives the world through what amounts to a mental "soda straw." When it aims that straw at one thing, all other objects—even those within your direct field of vision—recede into the background.
Experiment 1
Keeping your gaze riveted on the black cross, below, at all times, and holding the page 10 inches or less from your eyes, say the names of the three colors in each of the four strips. While you are concentrating on—but not directly looking at—one of the strips, the other three should dim in your consciousness, even though you haven't shifted your gaze away from those neglected color strips.
Cognitive psychologists call this phenomenon selective attention, a neural process by which the "volume knob" on one set of sensory inputs is turned up at the same time the intensity settings of all other stimuli are turned down.
Experiment 2
Having fiddled with the mental "controls" that steer your awareness toward different locations, now learn how it's possible to filter incoming information according to other attributes, such as color. Focus on the cross again, but this time say aloud the name of each of the six distinct colors, immediately followed by the total number of times that particular color appears on all four strips. Notice that in contrast with experiment 1, in which you couldn't concentrate on more than one strip at a time, here your soda straw widened its "field of view" to take in all four strips at once as it registered multiple instances of single colors. In addition to its other controls, your mental soda straw appears to have a zoom knob.
Experiment 3
Your brain calls up remembered images through the same conduit it uses to take them in live. Close your eyes and visualize everything inside your living room, including the furniture, walls, and artwork. As you scan your memory, notice that even though your brain stores the contents of your living room in surprising detail, it only "sees" these objects one at a time, more or less. You may be able to "zoom out" to recall several parts of your living room at once, but when you do, the details of individual objects will become a mental blur. This blurring effect illustrates an important property of selective attention: Your brain not only discards information that's outside the soda straw but is able to slurp up only a limited amount of detail within the soda straw as well.
To make matters worse, inputs from all your sense organs must flow through the same narrow straw and may block each other. For instance, talking on a cell phone while driving "blinds" you to important details about traffic. This may explain why dipping your mental soda straw into an active phone conversation while driving is equivalent to dipping it into a stiff shot of whiskey.
