12.10.2009

worth a thousand words

When it comes to memory, researchers have known for more than 100 years that pictures and text follow very different rules. Put simply,the more visual the input becomes, the more likely it is to be recognized—and recalled. The phenomenon is so pervasive, it has been given its own name: the pictorial superiority effect, or PSE.


Human PSE is truly Olympian. Tests performed years ago showed that people could remember more than 2,500 pictures with at least 90 percent accuracy several days post-exposure, even though subjects saw each picture for about 10 seconds. Accuracy rates a year later still hovered around 63 percent. In one paper—adorably titled “Remember Dick and Jane?”—picture recognition information was reliably retrieved several decades later.

Sprinkled throughout these experiments were comparisons with other forms of communication. The favorite target was usually text or oral presentations, and the usual result was “picture demolishes them both.” It still does. Text and oral presentations are not just less efficient than pictures for retaining certain types of information; they are way less efficient. If information is presented orally, people remember about 10 percent, tested 72 hours after exposure. That figure goes up to 65 percent if you add a picture.

The inefficiency of text has received particular attention. One of the reasons that text is less capable than pictures is that the brain sees words as lots of tiny pictures. Data clearly show that a word is unreadable unless the brain can separately identify simple features in the letters. Instead of words, we see complex little art-museum masterpieces, with hundreds of features embedded in hundreds of letters. Like an art junkie, we linger at each feature, rigorously and independently verifying it before moving to the next. The finding has broad implications for reading efficiency. Reading creates a bottleneck. My text chokes you, not because my text is not enough like pictures but because my text is too much like pictures. To our cortex, unnervingly, there is no such thing as words.

That’s not necessarily obvious. After all, the brain is as adaptive as Silly Putty. With years of reading books, writing email, and sendingtext messages, you might think the visual system could be trained torecognize common words without slogging through tedious additional steps of letter-feature recognition. But that is not what happens. No matter how experienced a reader you become, you will still stop and ponder individual textual features as you plow through a book, and you will do so until you can’t read anymore. Perhaps, with hindsight, we could have predicted such inefficiency. Our evolutionary history was never dominated by text-filled billboards or Microsoft Word. It was dominated by leaf-filled trees and saber-toothed tigers. The reason vision means so much to us may be as simple as the fact that most of the major threats to our lives in the savannah were apprehended visually. Ditto with most of our food supplies. Ditto with our perceptions of reproductive opportunity.

The tendency is so pervasive that, even when we read, most of us try to visualize what the text is telling us. “Words are only postage stamps delivering the object for you to unwrap,” George Bernard Shaw was fond of saying. These days, there is a lot of brain science technology to back him up.













Learn more:
Getty Images video (from Brain Rules DVD)
Death by PowerPoint (from Brain Rules DVD)


3 comments:

tracy said...

Just bought your book and have finished first chapter on excercise. It needs more pictures. JUST KIDDING.
Great post, thanks.

Susan WB said...

What about blind and/or visually impaired people? I work in English language education for immigrant and refugee adults. One of the best tools we have for teaching is, of course, pictures! (and gestures/miming, too.) But recently we've had learners coming to our program who've lost their sight, and have had to adapt our teaching methods. Teachers try to substitute pictures with manipulate-able objects/tactile information, but often just have to rely on verbal communication. Do you have/know of any research on how well the visually impaired remember oral language as compared to sighted people? My guess is that they remember better because they attend to it more than those of us who are constantly distracted by input from our eyes.

Trina Webb said...

That's really a marvelous post. Some interesting thoughts here. Thanks for this post