Short Term Memory - What Is Memory: Improving Memory Understanding Age Related Memory Loss

Content provided by the Faculty of the Harvard Medical School

Short-term memory

This is information that the mind stores temporarily, encompassing what you need to remember in the next few seconds or minutes. Short-term memories include, for example, the name of the person who just spoke at a dinner party (as well as what that person said), and the date and time of the appointment you just made — and must remember only until you write it in your date book.

Working memory is a form of short-term memory that involves actively holding information and manipulating it. For example, working memory comes into play when you remember prices at the supermarket while at the same time performing a computation with them so you can compare costs.

Short-term memories are supposed to be fleeting. They turn over at a high rate because they're continually being replaced by new ones, and there are only so many short-term memories you can keep in mind. Research shows that the average person can hold only about seven (plus or minus two) unrelated "bits" of information in mind at one time. That's why it's easier to remember a seven-digit phone number than a longer number such as the identification number on a driver's license.

The relatively transient nature of your short-term memory is actually beneficial because it allows you to discard unnecessary information. Imagine what life would be like if you kept every short-term memory — the name of the telemarketer who called your house an hour ago, the price of each dish you ordered from a Chinese restaurant, what color tie your friend wore yesterday. Your mind would be so overloaded with trivia that you'd have trouble focusing on the things that really are important. It would be as if you kept all your junk mail and let it bury your personal letters, bank statements, and other important documents. A famous case in the scientific literature describes a man who possessed a seemingly limitless capacity to remember detail — and how this talent undermined his ability to lead a normal life. He retained so much information that he was unable to organize it into meaningful categories. This made it difficult for him to manage his life, set goals, and maintain intimate relationships.

Short-term memory has another limitation. It's fragile and easily disturbed by interruptions. If you're trying to remember a phone number and someone walks into the room and asks you a question, chances are you'll forget the number and have to look it up again. That additional bit of information (the question) "bumps" the short-term memory out of your awareness.

Last updated:	January 23, 2007