Think Smart: A Neuroscientist's Prescription for Improving Your Brain's Performance (12 page)

The same principle holds true if you want to remember numbers. For most people, numbers are harder to remember than words simply because mentally “seeing” numbers isn’t as easy as envisioning objects. While it’s easy to imagine a shoe, a watch, and a pen, how do you mentally envision the number 313 or 4,573? There are several ways of doing that.

When I asked puzzle master Scott Kim to quickly reverse the seven-digit span 0785621, he responded within a second or so after I finished reading the number to him. Since he knew that the string would contain seven numbers, he broke it down into a four-digit number, 0785, separated by a space from the three digits of 621. He then simply reversed the three-digit number to yield 126 and the four-digit number to yield 5870.

“If the digit span was longer, I would have probably associated the higher numbers with a higher musical pitch and the lower numbers with a low pitch,” Scott explained to me. “Or I might try something else and imagine the numbers occupying places on a grid. Or I might use my kinesthetic sense and imagine myself touching the numbers, with each of the numbers having its own special ‘feeling.’ ”

Others have favored additional strategies. Memory wizard Rajan Mahadevan devised a system based on his memorization of telephone area codes. When memorizing 212 he associated it with New York City, the sequence 202 he associated with Washington, D.C., 410 with Baltimore, and so on.

My personal favorite method for remembering numbers is to convert them into images and then recall the numbers by reconverting the images to numbers. Here’s how to do that:

Memorize the following images that employ a rhyming word for the numbers from 0 to 10.

Because of the rhyming you’ll find the list easy to memorize. Each time you see a 0, imagine Leonardo DiCaprio or your favorite movie hero. When you see 7, you can imagine an angel floating on a cloud and playing the harp. If you don’t fancy that image, picture a loaf of bread;
leaven
is an alternative rhyming word for
seven
and brings to mind a loaf of (leavened) bread. The other eight numbers are easier to remember because they involve universal images.

Take the number sequence 2023627834 and memorize it using this system. Here’s one way of doing it. Group the first three numbers into the image of Leonardo DiCaprio holding a shoe in each hand (202). In order to remember 36, picture a power saw reducing a tree to a pile of sticks. For 27, imagine an angel playing a harp in the form of a shoe. For 834, envision a skate coursing along an icy pond shaped in the form of a tree and crashing into a barn door. Other images will work just as well. In fact, you are more likely to remember images that you come up with yourself because in the process of composing them you will be utilizing
association
and
elaboration,
the two most basic memory techniques.

Whenever you attach a word or a name to something familiar, you are practicing association (associating a face with a name, for example). Sometimes the association comes easily. My dermatologist is named David Spot; the most famous neurologist in the mid-twentieth century was W. Russell Brain. No problem remembering either of them. Other names, such as that of Dr. Paula Trzepacz, my successor as president of the American Neuropsychiatric Association, aren’t as easily reduced to an image.

Elaboration is another basic memory technique. The more meaning you can give to the thing to be remembered, the more successful you will be in recalling it. One way of doing this is to devise a sentence that can work as a code for recalling the number. A famous example is the sentence devised by the British mathematician Sir James Jeans to represent pi, the ratio of a circle’s circumference to its diameter. “How I want a drink, alcoholic of course, after the heavy lectures involving quantum mechanics!” The number of letters in each word in that sentence when read in sequence corresponds to the first fourteen decimal places of pi: 3.14159265358979.

In medical school I employed a similar technique to learn the names of the twelve cranial nerves by memorizing this sentence: “On Old Olympus’s towering tops a Finn and German vied at hops.” The first letter of each word corresponds to the first letter of each cranial nerve (olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, auditory, glossopharyngeal, vagus, accessory, and hypoglossal).

What do these various memory “tricks” have in common? Each method forces the memorizer to focus attention on the information to be memorized. This is the key requirement for the successful recall of a name, for instance. Most failures in name recall result from inattention rather than a memory failure. As mentioned earlier, the person who cannot recall a name at a later point after an introduction probably wasn’t really listening to the name during the introduction. Since she didn’t really hear it, she can’t later remember it. Listening closely, asking for a repetition of the name, inwardly repeating it, and finally trying to come up with an image to link name and face—these steps will greatly increase the likelihood of later recall.

Since we are visual creatures on the basis of our brain’s organization (the number of fiber tracks conveying visual information within the brain far surpasses the number of fiber tracks conveying any other form of sensory information), we increase our chances of remembering something by converting it into a visual format. The odds of correctly recalling the name can be further improved by using stark and even bizarre images. Memory savants differ from the rest of us as a result of their astounding ability to convert information of any type into pictures.

A useful method for remembering textbook material is encoded in the mnemonic PQ4R, which is shorthand for the steps involved. First,
preview
the pages to be remembered by quickly scanning through the chapter and noting the headings. Next, compose
questions
about what you’ve read. Then perform four Rs:
read
the text in search of answers to those questions;
reflect
on what you’ve read and try to come up with examples of how you can apply it;
recite
the material after you have learned it. The easiest way of doing that is to put the book to the side and recall and recite what you have just read. The last step in PQ4R is to
review:
try to recall and summarize the main points. PQ4R will work even better if you use a voice recorder. That way the information enters the brain through both the visual and the verbal pathways.

I regularly use the PQ4R method and can vouch for its effectiveness. I prepared for my board examination in neurology by quickly reading background books, formulating questions about what I had read, and speaking those questions into a voice recorder. I then searched for answers in the text, reflecting out loud into the recorder the implications of what I had just learned for how I would care for my patients. Next, I recited what I had learned and recorded it. Finally, I summarized and reviewed everything aloud. At odd moments over the next few weeks I either listened to the recordings (while driving) or during more leisurely moments I reviewed the written material while listening to my voice summarizing it on the recording.

In order to proceed further in strengthening your memory, I suggest two formal memory courses that you can do at your own pace. A short beginner’s course can be found at
www.NeuroMod.org
, the website of the Neural and Cognitive Modeling Group at the University of Amsterdam. It provides a discussion of the basic principles by Professor Jaap Murre. When visiting that site, click on “Human Memory” and select “online memory improvement course.”

You’ll find a more rigorous course at Kevin Jay North’s
www.Thememorypage.net
. When visiting that site, click “Tutorials” and select “How to Improve Your Memory.” This includes novel techniques for memorizing lists and numbers as well as instructions on the use of peg words. I found most useful his tips on increasing one’s reading retention—you can find it by clicking on “Tips&Tricks” from the main menu. For really advanced memory techniques, North provides a free link to the Memory Master Training Course, essentially a book-length presentation of memory techniques. There are also some strictly-for-fun applications such as a card-counting technique coupled with an online test of your skill after you’ve learned the method.

After improving your memory by using one of these methods, you are probably curious enough to ask, “What is the greatest memory performance that I can reasonably expect to achieve?”

In search of an answer to that question, I watched Morley Safer’s
60 Minutes
interview with Daniel Tammet, one of an estimated only fifty true memory savants living in the world today. Thanks to his wire-framed glasses, prominent front teeth, and close-cropped hair, Tammet fits most people’s image of a savant. But Tammet differs from the typical savant in several ways. He isn’t retarded but has Asperger’s syndrome, a form of autism marked by awkwardness and difficulty in social situations coupled with sometimes bizarre talents and interests. For instance, people with Asperger’s can be found within the ranks of compulsive hoarders and collectors, especially collections involving odd items that are of little interest to the average person (bottle caps, for example). Often a person with Asperger’s displays superior intelligence in selective areas, such as memory and mathematics. Finally, their thought processes are marked by prominent defects in imagination and empathy.

During the interview Tammet appears shy but likable, engaging in a relaxed conversational repartee marked by a social facility and occupational success that sets him apart from the typical person with Asperger’s. He runs a successful Web-based business for language tutorials.

As I watched Tammet describe the virtuoso memory performance that has made him world famous, two things occurred to me. First, the memory performance of a savant like Tammet isn’t simply an extreme example of what we all could do if we simply stopped lazing around and put in additional effort. If you need convincing about this, try reciting as many as you can of the numbers of pi. As a convenient round-off in trigonometry, most of us learned to use 3.14 as a working approximation of pi. But pi is an infinite number with the digits to the right of the decimal point extending into infinity. “It isn’t possible for someone to write down the number pi exactly, even if he or she had a piece of paper as big as the universe to write it on,” writes Tammet in his autobiography,
Born on a Blue Day.

Even though pi is infinite, that hasn’t stopped memory virtuosos from competing with each other for the distinction of reciting the longest string of its digits. Various techniques have been used. As mentioned earlier, anyone can easily recite pi to fourteen places by converting numbers into a sentence with the words composed of letters corresponding to the numbers. Others convert the numbers into familiar patterns that vary according to interests and life experiences (athletic performance statistics, historical dates, zip codes) and enable the mnemonist to store extended number sequences in long-term memory. By using a conversion process, the Indian mathematician Rajan Mahadevan in 1981 correctly recalled the first 31,811 digits of pi.

On March 14, 2004—International Pi Day—Tammet accepted the challenge of exceeding the European record for reciting from memory as many digits of pi as possible (22,500 digits was the European record at that time). Tammet’s method, however, involved more than a simple conversion process:

“When I look at a sequence of numbers, my head begins to fill with colors, shapes, and textures that knit together spontaneously to form a visual landscape. To recall each digit, I simply retrace the different shapes and textures in my head and read the numbers out of them.”

As this comment makes clear, Tammet based his performance on synesthesia, specifically a form known as grapheme-color synesthesia, where numbers and individual letters of the alphabet (collectively referred to as graphemes) are perceived as colored. “I see numbers as shapes, colors, textures, and motions,” Tammet said. He also uses number-form synesthesia: a mental map that automatically and involuntarily springs to mind whenever he thinks of numbers. Thus the numbers don’t line up along a horizontal line but, as Tammet describes it, “as the sequence of digits grows, my numerical landscapes become more complex and layered, until—as with pi—they become like an entire country in my mind, composed of numbers.”

Over five hours and nine minutes, Tammet recited 22,514 digits to beat the earlier British and European record. “As I recited I could feel myself becoming absorbed within the visual flow of colors and shapes, textures and motion, until I was surrounded by my numerical landscape.”

I think it’s fair to say that Tammet’s memory technique isn’t an option for those of us who aren’t synesthetes. But we can still improve our memory by following his advice to cultivate “single-mindedness along with a strong drive to analyze detail and identify rules and patterns.” Here are several rules that will help you do that:

1.
Pay attention.
Mentally focus on the information you want to learn to the exclusion of everything else.

2. When encountering a new piece of information that you want to remember,
employ as many sensory faculties as possible.
Listen to yourself speaking the name or fact; write it down; read aloud what you’ve written; finally, with the index finger of your dominant hand, write it on the palm of your other hand. This sequence funnels the information through the visual, auditory, and tactile channels.

3.
Put the information you want to remember into an image,
preferably one that is captivating because of its novelty and high-image content.