Free Moonwalking With Einstein by Joshua Foer Page B

to know that?) Do you have electrical wiring expertise? (Really?)
    For someone who wants to know what’s being done to him so that he might someday tell other people about it, being the subject of a scientific study can be exceedingly trying.
    “Why exactly are we doing this?” I’d ask Tres.
    “I’d rather not tell you everything right now.” (If there was something I was going to be tested on later—and as it turned out, there was—he didn’t want me to know.)
    “How did I do on that last test?”
    “We’ll let you know when this is all done.”
    “Can you at least tell me about your hypothesis?”
    “Not now.”
    “What’s my IQ?”
    “I don’t know.”
    “High, though?”

    The mind-numbing memory exam that SF, the Carnegie Mellon undergraduate, took over and over again for 250 hours for two years is known as the digit span test. It is a standard measure of a person’s working-memory capacity for numbers. Most people who are given the test are like SF when he started: They’re only able to remember seven plus-or-minus two digits. Most people remember those seven plus-or-minus two numbers by repeating them over and over again to themselves in the “phonological loop,” which is just a fancy name for the little voice that we can hear inside our head when we talk to ourselves. The phonological loop acts as an echo, producing a short-term memory buffer that can store sounds just a couple seconds, if we’re not rehearsing them. When he began participating in Chase and Ericsson’s experiment, SF also used his phonological loop to store information. And for a long time his scores on the test didn’t improve. But then something happened. After hours of testing, SF’s scores started inching up. One day he remembered ten digits. The next day it was eleven. The number of digits he could recall kept rising steadily. He had made a discovery: Even if his short-term memory was limited, he’d figured out a way to store information directly in long-term memory. It involved a technique called chunking.
    Chunking is a way to decrease the number of items you have to remember by increasing the size of each item. Chunking is the reason that phone numbers are broken into two parts plus an area code and that credit card numbers are split into groups of four. And chunking is extremely relevant to the question of why experts so often have such exceptional memories.
    The classic explanation of chunking involves language. If you were asked to memorize the twenty-two letters HEADSHOULDERS-KNEESTOES, and you didn’t notice what they spelled, you’d almost certainly have a tough time with it. But break up those twenty-two letters into four chunks—HEAD, SHOULDERS, KNEES, and TOES—and the task becomes a whole lot easier. And if you happen to know the full nursery rhyme, the line “Head, shoulders, knees, and toes” can effectively be treated like one single chunk. The same can be done with numbers. The twelve-digit numerical string 120741091101 is pretty hard to remember. Break it into four chunks—120, 741, 091, 101—and it becomes a little easier. Turn it into two chunks, 12/07/41 and 09/11/01, and they’re almost impossible to forget. You could even turn those dates into a single chunk of information by remembering it as “the two big surprise attacks on American soil.”
    Notice that the process of chunking takes seemingly meaningless information and reinterprets it in light of information that is already stored away somewhere in our long-term memory. If you didn’t know the dates of Pearl Harbor or September 11, you’d never be able to chunk that twelve-digit numerical string. If you spoke Swahili and not English, the nursery rhyme would remain a jumble of letters. In other words, when it comes to chunking—and to our memory more broadly—what we already know determines what we’re able to learn.
    Though he’d never been properly taught the technique of chunking, SF figured it out on his own. An avid