By Mr Daniel Hansson

Important definitions Encoding: When an experience is converted into a memory construct Storage: When a memory is stored over time Retrieval: Recall of memories

Atkinson-Shiffrin (1968)

Sensory store A temporary buffer store holding information from the environment very briefly in an unprocessed state Is modality specific, i.e. information is held in the form in which it is received (visual, auditory, tactile or olfactory) E.g. iconic (visual) and echoic (auditory). Information not attended to is forgotten Sperling (1960) has demonstrated that the capacity of the sensory store is at least 12 items, but it is probably vast

Short term memory (STM) What we are attending to, our awareness Has limited capacity: Only about 7 items or chunks can be stored at a time. (Miller, 1956) Has limited duration: Storage is very fragile and information can be lost with distraction (displacement) or passage of time (decay), between seconds) (Peterson & Peterson, 1959) Encoding is primarily acoustic.

Long term memory (LTM) Has theoretically unlimited capacity Encodes memories by meaning Information that is rehearsed in short term store may be stored in long term store Information is stored a longer time Forgetting in long term memory can occur through interference of memories, decay, or repression Cues, the same emotional states or environments where a memory was encoded can aid recall

Supporting research for a short term and long term store Miller (1956) has demonstrated that the capacity of the short term store is 7+-2 information units. Glanzer and Cunitz (1966) have demonstrated that there are separate memory stores, because of primacy and recency effects (the first and last items of memory lists are more likely to be recalled) This is because the first items are rehearsed and enters long term store and the last items are still in STM. Case studies, such as the one of HM (Milner, 1950) demonstrates that there are separate memory stores, because HM had an almost intact long term memory but was not able to learn new things (STM). Peterson & Peterson (1959) have demonstrated that the duration of STM is about 20 seconds.

Strengths of the model Supporting research The experimental research is well controlled Brain research supports that there are different localizations of memory mechanisms in the brain The model can account for primacy and recency effects The model has generated a lot of research into memory

Weaknesses of the model The model is criticized of being to linear (research suggests that the memory stores work more unitary. For instance, LTM may influence what we attend to and what we store in STM Cowan (2000) has suggested that the number of items to be stored in STM is more likely to be 4 There are other ways than just rehearsal and attention to memorize, such as through meaning (e.g. schemas) and emotion (e.g. flashbulb memories) Ecological validity problem of the supporting experimental research (this is not the usual way we memorize, unless we encode phone numbers, shopping lists or vocabulary) A possible cultural bias of the model. Studies (e.g. Cole and Scribner, 1974) show that children without schooling do not show primacy effect (do not rehearse information) Baddeley and Hitch (1974) have demonstrated that STM is not just a unitary store and consists of several components (e.g. visuospatial sketchpad, phonological loop, central executive) Research suggests that we do not have one, unified LTM, but different types of LTM, such as episodic (memory of events) and semantic LTM (general knowledge) and procedural memory (memories of skills)