Your Brain: The Missing Manual

Short-Term Memory

Short-term memory is the most fleeting type of memory. It holds onto a few chunks of information while you're actively thinking about them. If your attention wanders, the information is tossed out in less than a minute, but you can hold on to details for longer by repeating them continuously. Short-term memory is how you remember the toll-free phone number for a revolutionary piece of exercise equipment between seeing it on a late-night infomercial and reaching the phone.

Short-term memory is notoriously limited. Some believe it holds five to nine chunks of information, others claim it holds just four, but all agree that the total number is a few items short of your grocery list. Scientists also disagree on exactly how short-term memory is stored in the brain. But it is at least partly linked to current electrical activity taking place in your neurons—in other words, the pattern of signal transmission that's ricocheting through your head right now. This is markedly different from long-term memory, which depends on permanent physical changes in your brain.

It's important to realize that the five or so pieces of information held in short-term memory aren't detailed concepts. More accurately, short-term memory holds pointers to the more detailed conceptual information that's stored permanently in your brain.

For example, if you think of the items cat, dog, and zucchini, you don't actually have a full conceptual representation of any of these items in your short-term ...