Short-term memory (STM) is a temporary storage system that processes incoming sensory memory; sometimes it is called working memory. Short-term memory takes information from sensory memory and sometimes connects that memory to something already in long-term memory. Short-term memory storage lasts about 20 seconds. George Miller (1956), in his research on the capacity of memory, found that most people can retain about 7 items in STM. Some remember 5, some 9, so he called the capacity of STM 7 plus or minus 2.
Think of short-term memory as the information you have displayed on your computer screen—a document, a spreadsheet, or a web page. Then, information in short-term memory goes to long-term memory (you save it to your hard drive), or it is discarded (you delete a document or close a web browser). This step of rehearsal, the conscious repetition of information to be remembered, to move STM into long-term memory is called memory consolidation.
You may find yourself asking, “How much information can our memory handle at once?” To explore the capacity and duration of your short-term memory, have a partner read the strings of random numbers (see the adjacent Figure) out loud to you, beginning each string by saying, “Ready?” and ending each by saying, “Recall,” at which point you should try to write down the string of numbers from memory.
Note the longest string at which you got the series correct. For most people, this will be close to 7, Miller’s famous 7 plus or minus 2. Recall is somewhat better for random numbers than for random letters (Jacobs, 1887), and also often slightly better for information we hear (acoustic encoding) rather than see (visual encoding) (Anderson, 1969).
Test your working memory
Complete this online demonstration to test the capacity of your working memory
Watch a video
In this video published on the TED channel on Youtube, educational psychologist Peter Doolittle details the importance — and limitations — of your “working memory,” that part of the brain that allows us to make sense of what’s happening right now.
- Miller, G. A. (1956). The magical number seven, plus or minus two: Some limits on our capacity for processing information. Psychological Review, 68, 81–87.
- Jacobs, J. (1887). Experiments on “prehension.” Mind, 12, 75–79.
- Anderson, N. S. (1969). The influence of acoustic similarity on serial recall of letter sequences. Quarterly Journal of Experimental Psychology, 21(3), 248–255.
- This page was proudly adapted from Psychology published by OpenStax CNX. Oct 31, 2016 under a Creative Commons Attribution 4.0 license. Download for free at http://email@example.com.