Mind Performance Hacks

Hack #11. Consume Your Information in Chunks

Improve your short-term memory, your information processing, and your long-term memory by grouping the bits of data you come across into chunks.

Psychologist George A. Miller concluded in a classic 1956 experimental survey that human short-term memory can hold only seven items at a time, plus or minus two.¹Short-term memory bears the same relation to long-term memory in humans that RAM does to mass storage in a computer: short-term memory, which is temporary, is the gateway to human long-term memory, which is semi-permanent. Short-term memory is also where information that is currently being processed is stored (such as a phone number you're calling). Thus, it's important for not only short-term memory itself, but also long-term memory and information processing, to maximize the ability to use short-term memory.

Recent research suggests the magic number that short-term memory can hold might be somewhat lower than seven, at least for intellectually demanding tasks. Researchers at the University of Queensland found that 30 academics given a task of analyzing statistical interactions among variables—a task at which they were already expert—did not perform better than chance at analyzing interactions of five variables in timed tests. Also, they were not only worse at analyzing four-variable interactions than interactions involving three or two variables, but less confident of their answers as well.²

Whether the magic number is five or seven, people normally find it hard to remember more than a few small bits of information. If they recode the bits by clustering them into larger, more meaningful chunks, however, they can remember many more of the bits. In the next section, we will show that you can remember a large number of literal bits ( binary digits) by grouping them into more meaningful and comprehensible numeric chunks.

In Action

Here are 40 random binary digits. Examine them and spend as much time as you want memorizing them, then look away from this book and try to write them down. The only rule is that you may not convert them to another base, count them, restructure them, or use any other mnemonic trick to memorize them. You must memorize them by rote as you see them on the page. Are you ready? Go!

0011110111110111111100000010000010000011

How did you do? Probably not too well. If you did well, either you're a mutant with frontal lobes the size of a soccer ball, or you couldn't help but notice (for example) that the third group of 1s is seven bits long and is followed by six zeroes, then a 1 with five zeroes, and another 1 with five zeroes. In other words, you chunked them, you cheater!

Now, assuming you understand how to convert between binary (base two) and decimal [Hack #40], you can group these bits into bytes to produce five groups of eight bits, which you can recode to five decimal numbers, like this:

00111101  11110111  11110000  00100000  10000011
      61       247       240        32       131

Look away from the book again. Try to write down the five decimal numbers and then convert them to their original binary form. Go!

How did you do at remembering the binary numbers? Probably better this time. While writing this hack, I noticed that I was spontaneously able to recall all five decimal numbers hours later without any formal mnemonic tricks. Chunking is simply a superior way for humans to process data! Miller writes:

It is a little dramatic to watch a person get 40 binary digits in a row and then repeat them back without error. However, if you think of this merely as a mnemonic trick for exceeding the memory span, you will miss the important point that is implicit in nearly all such mnemonic devices. The point is that recoding is an extremely powerful weapon for increasing the amount of information that we can deal with. In one form or another, we use recoding constantly in our daily behavior; the kind of linguistic recoding that people do seems to me to be the very lifeblood of the thought processes.

Chunking is certainly central to many mnemonic hacks in this book, such as the Dominic System [Hack #6].

How It Works

The basis for the whole hack is recoding many small items that are difficult to distinguish (such as 40 bits) into a few distinct items (such as five decimal numbers). Five decimal numbers, even if they are not immediately meaningful to you, are few enough to retain in short-term memory. If some of them are meaningful to you, so much the better.

Rest assured that the technique applies to many phenomena other than binary numbers. Suppose you had a big pile of Scrabble tiles to memorize—say, 200 or so. If you could form them into words first, and then form the words into a sentence or paragraph, you'd have a much better chance of remembering the letters on the tiles.

In Real Life

When I was a broke psychology student, I often participated as a guinea pig in experiments at the Yale psychology and linguistics labs to earn pocket money. I had a few memorable experiences.

One experiment was designed to test the capacity of human short-term memory. A computer would flash strings of decimal digits rapidly on the screen, and the subject was supposed to type as many as she could back in. Although this was before I had made any serious study of mnemonic techniques, I instinctively chunked the digits into groups of two and three, effectively into numbers that I had made friends with [Hack #36]. I was able to beat the magic number of seven by about a factor of two without breaking a mental sweat. The experimenters seemed surprised and questioned me closely, apparently to determine whether duplicity was involved. I told them what I was doing, and they visibly relaxed; obviously, they knew about chunking, but apparently no one else who had participated in the experiment had used it.

End Notes

1. Miller, George A. 1956. "The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information." The Psychological Review, 63. http://www.well.com/user/smalin/miller.html.

2. Halford, Graeme S., Rosemary Baker, Julie E. McCredden, and John D. Bain. "How Many Variables Can Humans Process?" (January 2005). Psychological Science. Abstract at http://www.eurekalert.org/pub_releases/2005-03/aps-hmc030805.php.