Short Term Memory

• The human brain can usually retain 7 pieces of information at one time in the STM, however it is possible to retain more information through the process of chunking. This is dividing the information into chunks (meaningful units of information) which can more readily be remembered.
• Maintenance rehearsal involves repeating to yourself over and over again (silently or out loud) a piece of information that you are trying to memorise. This process extends the time information can be held in the STM.
• If you are trying to remember a list of words (or objects, letters, numbers, etc.), you are much more likely to remember the words at the start of the list (primary effect) and at the end of the list (recency effect). Overall this effect is called serial position effect.
• Primary effect occurs because the first words are well rehearsed and therefore become encoded and transferred to the LTM.

  The last seven or so objects are remembered because images of them are still present in the STM.

  The words in the middle of the sequence are not well retained by the majority of subjects because, by the time these images enter the STM, it is already crowded. Therefore many are forgotten before they can be rehearsed, encoded and stored in the LTM.
• Loss of items by displacement - Something of more importance pushed out the item of lesser importance in the STM.
• Decay - Something of more importance pushing out the item of lesser importance in the STM.
• Short-term memory (STM) – has a limited capacity and holds information for a short time. After this items will either be lost through displacement by new items or passed to the LTM. The capacity of the STM can be improved by ‘chunking’.
• STM holds about 7 items at one time (memory span). The items are only held for a short time (30 secs). During this time retrieval of information is

  very accurate, thereafter they are either transferred to LTM or lost by displacement or decay.
• The serial position effect states that recall is the best for objects shown at the end (recency effect), closely followed by those at the start (primacy effect)