Memory

What you need to know. Memory involves storage, retention and retrieval of information. Memories include past experiences, knowledge and thoughts. All information entering the brain passes through sensory memory and enters short term memory. Information is then transferred to long-term memory (LTM) or discarded.

Sensory memory. Lasts a few seconds and retains all of the visual or auditory input.

Short term memory (STM): memory span. This is how much information can be stored in the STM. Often measured by the ability to recall a series of numbers or words.

Short term memory (STM): serial position effect. This is a tendency to recall the first and last items of a list better than those in the middle.

Short term memory (STM): rehearsal. By repeating (or rehearsing) information, it can be kept in the short term memory. Repeating information means that it re-enters the STM (e.g. reciting a definition again and again). Rehearsing helps to transfer information from the STM to the LTM.

Short term memory (STM): improvement by ‘chunking’. Chunking information seems to improve its retention in STM. Grouping numbers together is a common example: The school’s phone number is 01506653725 It is much easier to remember 01506 653 725.

Short term memory (STM): loss of items by displacement and decay. This is effectively forgetting things! There are two theories: Information can only be held in the STM for 15-30 seconds. After this time it decays away (unless it is rehearsed). The STM has a limited capacity for information. When it is full, new information pushes out (displaces) older information.

Transfer of information from STM to LTM. Due to: 1. rehearsal (the more it is repeated the more likely it will end up in LTM); 2. organisation (grouping the information in a way that makes sense to you); 3. elaboration (adding meaning to the information).

Encoding Information that passes to LTM is said to be encoded. There are two types of encoding: Shallow encoding: repetition of something (the cortex stores semantic memories, the cortex stores semantic memories, the cortex stores semantic memories,…) Elaborative encoding: adding meaning to something which makes it easier to recall. This encoding often relates to information already stored in LTM (the cortex stores semantic memories which are my revision of facts so I am now needing to access these to answer the question properly!)

Retrieving information from LTM. Recalling memories is helped by contextual cues. When information is encoded, the setting of when/where this happened will help its retrieval. For example, think of a song where you know all of the words. Is it easier to recall all the words by singing the tune in your head (the way it was encoded) or by not using the tune and just writing the words out in a list? The headings used when organising information are often useful contextual cues.