Short-Term vs Long-Term Memory
Psychology: AQA A Level, topic 2.1.2
Short-Term Memory
Short-term memory (STM) is the point of processing sensory memory. This then determines whether information is moved into long-term memory or not.
Short-term memory (STM)
- Short-term memory (STM) is a temporary storage system that processes incoming sensory 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 (estimated to be between 18 and 30 seconds).
Information processing in STM
- Think of short-term memory as the information you have displayed on your computer screen - a document, a spreadsheet, or a web page.
- Information in short-term memory is stored in long-term memory if you save it to your computer's hard drive, or it is discarded if you close the webpage or delete the document.
- Rehearsal is the conscious repetition of information that you want to remember. This feels like repeating something over & over in your head.
- This step of rehearsal may help to move information from STM into long-term memory - which is called memory consolidation.
STM capacity
- In his research on the capacity of memory, George Miller (1956) found that most people can retain about seven items in STM.
- Some remember five, some nine, so he called the capacity of STM seven plus or minus two.
- Some factors affect our STM. For example, numbers recall is better than letters, and acoustic coding tends to be better than visual coding.
Summary
- Duration: 20 seconds.
- Capacity: seven +/- two items.
- Coding: primarily acoustic.
Long-Term Memory
Long-term memory is like the brain's hard-drive. It is theorised to have an unlimited capacity. Most of the time, information can be retained and moved back into short-term memory - but you may need a prompt.
Long-term memory (LTM)
- Long-term memory (LTM) is the continuous storage of information.
- Unlike short-term memory, the storage capacity of LTM has no limits.
- LTM contains everything that you can remember, even if it happened 2 minutes ago, weeks ago or years ago.
Information processing in LTM
- Sticking with the computer analogy, the information in your LTM would be like the information you have saved on the hard drive.
- Information stored on the hard drive isn't visible on your computer screen (or in your immediate short-term memory), but you could probably access (or remember) the information if you wanted to.
Strength of long-term memories
- Not all long-term memories are remembered equally strongly. It can be harder to remember some memories and prompts (or memory cues) can make it easier to access a memory.
- For example, you might easily recall a fact - “What is the capital of the United States?” - or a procedure - “How do you ride a bike?” - but you might struggle to recall the name of the restaurant you had dinner in when you were on holiday in France last summer.
- However, a prompt or memory cue about the owner of the restaurant or the first word of the name may help you recall the restaurant's name.
Summary
- Duration: unlimited.
- Capacity: unlimited.
- Coding: primarily semantic but can be others.
Test yourself on Short-Term vs Long-Term Memory
What is the term for the rehearsal process to move information from the short-term memory to the long-term memory?
Which of the following would be a normal number of items to retain in short-term memory?
Which scientist discovered that the capacity of short-term memory is seven +/- two?
What is sometimes necessary for a long-term memory to be recalled?
What is the storage capacity of LTM?