What constitutes a memory? Many of us may think of a memory as
something verbal—a line of haiku poetry we recited in fourth
grade—or something visual—a flashback to an angry look or loving
smile. But there are other types of memories we may not be conscious of at all,
including procedural memories involved in learning and mastering motor skills
like swinging a tennis racket. When you learn the proper upward follow-through,
for instance, this know-how (which some term "muscle memory") is
encoded in your neurons. And research suggests that sleep enhances such
memories, that you can become a better tennis player or musician or whatever not
just by practicing but also by "sleeping on" skills you've recently
acquired.—Susan K. Lewis
To see this intriguing phenomenon in action, try this simple test*
In the evening, open a word-processing document.
Tap out five numbers (e.g., "41324") in a
large font at the top of the page. This will be your reference; you can look at
the sequence as you do the next step.
Below the number, and using your
non-preferred (non-dominant) hand, start typing the sequence as fast as you can
for 30 seconds, each sequence on a new line. Don't correct mistakes; just keep typing. At the end of
30 seconds of typing, you have completed one trial. Repeat the typing task for
eight trials altogether, resting for 30 seconds between trials.
To quickly count how many correct sequences you tapped
out in each trial, use your word-processing program's "find and replace" feature (e.g., find "41324" and replace with "X"). Then just count
the number of X's per trial.
The next morning, repeat the exercise, using the same
five-number sequence and same hand.
Now, compare your performance on the last few trials of
day 1 (trials 6-8) to the first few trials of day 2 (trials 9-11).
How did you do? Let us know on
the NOVA scienceNOW discussion board.
* Many thanks to Matt Walker of
Harvard Medical School for suggesting this test, adapted from research he and
colleagues did for the 2002 study "Practice With Sleep Makes Perfect:
Sleep Dependent Motor Skill Learning." Neuron 35:205-211.
Images: (fingers typing) © istockphoto.com/blackred