You Still Need Your Brain, por Daniel T. Willingham – The New York Times

Foto: Marion Fayolle

Most adults recall memorizing the names of rivers or the Pythagorean theorem in school and wondering, “When am I ever gonna use this stuff?” Kids today have a high-profile spokesman. Jonathan Rochelle, the director of Google’s education apps group, said last year at an industry conference that he “cannot answer” why his children should learn the quadratic equation. He wonders why they cannot “ask Google.” If Mr. Rochelle cannot answer his children, I can.

Google is good at finding information, but the brain beats it in two essential ways. Champions of Google underestimate how much the meaning of words and sentences changes with context. Consider vocabulary. Every teacher knows that a sixth grader, armed with a thesaurus, will often submit a paper studded with words used in not-quite-correct ways, like the student who looked up “meticulous,” saw it meant “very careful,” and wrote “I was meticulous when I fell off the cliff.”

With the right knowledge in memory, your brain deftly puts words in context. Consider “Trisha spilled her coffee.” When followed by the sentence “Dan jumped up to get a rag,” the brain instantly highlights one aspect of the meaning of “spill” — spills make a mess. Had the second sentence been “Dan jumped up to get her more,” you would have thought instead of the fact that “spill” means Trisha had less of something. Still another aspect of meaning would come to mind had you read, “Dan jumped up, howling in pain.”

The meaning of “spill” depends on context, but dictionaries, including internet dictionaries, necessarily offer context-free meanings. That’s why kids fall off cliffs meticulously.

Perhaps internet searches will become more sensitive to context, but until our brains communicate directly with silicon chips, there’s another problem — speed.

Quick access is supposed to be a great advantage of using the internet. Students have always been able to look up the quadratic equation rather than memorize it, but opening a new browser tab takes moments, not the minutes required to locate the right page in the right book. Yet “moments” is still much slower than the brain operates.

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Speed matters when the quadratic equation is part of a larger problem. Imagine solving 397,394 x 9 if you hadn’t memorized the multiplication table. Sure, you could look up 4 x 9, but you could easily lose the thread of the problem as you did so. That’s why the National Mathematics Advisory Panel listed “quick and effortless recall of facts” as one essential of math education.

Speed matters for reading, too. Researchers report that readers need to know at least 95 percent of the words in a text for comfortable absorption. Pausing to find a word definition is disruptive. Online, the mere presence of hyperlinks compromises reading comprehension because the decision of whether or not to click disrupts the flow of understanding.

Deeper knowledge of words also helps. Your knowledge of what a word means, how it’s spelled and how it sounds are actually separate in the brain. That’s why you may recall one but not the others, as when you know what you want to say (“someone who owes money”) but can’t find the word (“debtor”). Good readers have reliable, speedy connections among the brain representations of spelling, sound and meaning. Speed matters because it allows other important work — for example, puzzling out the meaning of phrases — to proceed.

Using knowledge in the head is also self-sustaining, whereas using knowledge from the internet is not. Every time you retrieve information from memory, it becomes a bit easier to find it the next time. That’s why students studying for a test actually remember more if they quiz themselves than if they study as they typically do, by rereading their textbook or notes. That parades the right ideas before the mind, but doesn’t make them stick. In the same way, you won’t learn your way around a city if you always use your GPS, but you will if you work to remember the route you took last time.

The brain beats the internet when it comes to context and speed, but the internet clobbers the brain when it comes to volume. You can find any fact on the internet, even alternative ones. Your brain, in contrast, is limited, so how should we choose what to learn?

Students should learn the information for which the internet is a poor substitute. Getting information from the internet takes time, so they should memorize facts that are needed fast and frequently. Elementary math facts and the sounds of letters are obvious choices, but any information that is needed with high frequency is a candidate — in algebra, that’s the quadratic equation.

The internet is poor at putting information in context. Kids who look up the quadratic equation may end up like the child who looked up “meticulous”; they have a definition, but they don’t have the background knowledge to use it correctly. Students should learn not only the formula but also why it works and how it connects to other math content. That’s how contextual knowledge develops in the brain, and that’s why vocabulary instruction seldom consists of simple memorization of definitions — students are asked to use the words in a variety of sentences. The same should be true of more advanced concepts and for the same reason.

It’s a grave mistake to think Google can replace your memory. It can, however, complement it, if we keep in mind what each does best.