Basic overview- 3 points to remember
o Developed by ATKINSON AND SHIFFRIN in 1968
o It explains how information flows from one storage system to another
o It has THREE permanent stores - sensory memory, short term memory and long term memory
Sensory register - 5 points to remember
o Receives information from our senses - what we eat, hear and smell- and is MODALITY SPECIFIC (info held in same way as it is registered, such as taste is held as taste.)
o Capacity - lots of information, but we only remember it if it is paid attention to!
o Duration - 1/4 second, visual and 4 seconds, auditory
o The processing in sensory memory is mostly unconscious so is hard to experiment on it
o Sperling (1960) indicated this register holds at least 9 items, but for a very brief period
The short term memory - 4 points to remember
o It is a temporary store which contains information currently being thought about
o Encoding - mainly ACOUSTIC and is based on sounds. BADDELEY researched this as he found acoustically similar words more difficult to recall than acoustically different words
o Capacity - 7+/-2 but if you CHUNK items together into units, capacity is better. JACOBS' digit span technique found by giving participants increasingly longer lists of letters/numbers, the letter capacity was 7 items and number capacity was 9. If participants fail on 50% of the tasks they have reached their digit span capacity.
o Duration - 18-30 seconds, but rehearsal will increase duration. PETERSON + PETERSON researched this by making participants count backwards (interference task) in threes. Memory lasted no longer than 18 seconds. If rehearsed, it eventually becomes a perament feature of the LTM. This study can also be used as evidence for the FUNCTIONAL SEPERATION of LTM and STM.
Popular study - Alan Baddeley (1966) - 5 points to
o AIM- to examine whether encoding in STM is primarily ACOUSTIC (sounds) or SEMANTIC (meaning)
o METHOD- 75 participants presented with one of four word lists repeated four times. List A was acoustically similar words, List B was acoustically dissimilar words, List C was semantically similar words and List D was semantically dissimilar words. To test STM they were given a list containing the original words in the wrong order and had to rearrange them in the right order.
o RESULTS - Participants given List A (acoustically similar) performed the worst with a recall of only 10% as they confused similar sounding words. Recall for the other Lists was comparatively good with 60-80% recall.
o CONCLUSION- The study suggests there was acoustic confusion in STM, suggesting it is encoded on an acoustic basis
o EVALUATION- Baddeley's findings make 'cognitive sense.' and can be applied to everyday life. It was a laboratory study and therefore shows causality but may lack ecological validity. It can be replicated for reliability.
The Primary- Recency effect - 7 (short) points to
o Where more words are recalled at the beginning and end of a task
o The PRIMARY effect is better recall of words at the beginning as have been transferred to the LTM
o The RECENCY effect is better recall of words at the end as they are still in the STM
o The words in the middle have been displaced from the STM but not yet consolidated into the LTM
o This is strong evidence of the FUNCTIONAL SEPERATION of the LTM and STM and therefore supports the MSM
o The study by MURDOCK (1962) is good evidence for the Primary-Recency effect
o Rehersal shows how items are transferred from STM to LTM
AO2 evaluation of studies - 2 points to remember
o ECOLOGICAL VALIDITY - studies carried out in a LAB to ensure control over extraneous variables and so they don't apply to an outside setting. They are also TRIVIAL TASKS and aren't important to participants. Remebering trigrams (Peterson + Peterson) is not what you do in real life!
o POPULATION VALIDITY - most memory experiments were carried out on STUDENTS. it is difficult to suggest that All people will use memory in a similar way.
AO2 short term memory evaluation points - 3 points
o STM is not restricted to ACOUSTIC CODING. The small difference between SEMANTICALLY SIMILAR (64%) and SEMANTICALLY DISSIMILAR (71%) lists suggests there is some SEMANTIC encoding in the STM. We also remember visual images, such as faces that the STM would find difficult to encode acoustically.
o There may be INDIVIDUAL differences in STM capacity. DANEMAN AND COOPER found capacity ranged fom 5-20 items between those with advanced and poor reading comprehension.
o REITMAN suggested tht the brief duration in the STM may be due to DISPLACEMENT, as new information is 'kicking out' the old information due to its LIMITED CAPACITY.
The long term memory - 4 points to remember
o Involves the STORAGE of information over extended periods of time. Forgetting in LTM may not be due to loss of info but for retrieval problems.
o Encoding - uses mainly SEMANTIC encoding and is based on meaning. BADDELEY also researched this using the same procedure as the STM study, but with an interval before recall where the participants did another task (interference task.) Semantically similar words had a much lower recall than the other lists, suggesting semantic confusion in LTM.
o Capacity - UNLIMITED. LINTON investigated this by spending 6 years making a diary of 5,500 personal events and found each month she had excellent recall of dates.
o Duration- A LIFETIME (potentially) lasts longer if originally well learned. BARICK ET AL showed 400 participants aged 17-74 sets of photos and asked them to identify them. Those who left school in the last 25 years recalled 90% of faces and names, whilst those who had left 48years ago recalled 80% names and 70% faces, suggesting memory for faces is long lasting.
AO2 long term memory evaluation points - 3 points
o It is difficult to see how smells and tastes could be encoded SEMANTICALLY and reason suggests that songs must be acoustically, supporting the idea of several forms of encoding in the LTM
o Diary studies (used in capacity, such as Linton) are a type of CASE STUDY and therefore are not REPRESENTATIVE of the general population
o Certain forms of info may have a longer DURATION than others. CONWAY ET AL found that statistical information is retained longer, possibly as it involves learning of SKILLS rather than plain facts.
AO2 evaluation of MSM - Strengths - 4 points to re
o There is strong EVIDENCE to support the components of the model
o The model provides an account of memory in therms of both STRUCTURE and PROCESS. The structures are the three stores and the processes are attention and verbal rehersal.
o The model has clear PREDICTIONS of memory which means studies can be conducted to test it.
o The primary recency effect supports the idea of the LTM and STM being separate stores. Clinical studies also support this, such as HM, who, as a result of anterograde amnesia had a normal STM yet a impaired LTM as he was unable to learn new info. Other support for separate stores comes from people affected by Korsakov's syndrome as they seem to have difficulty transferring Info from STM to LTM.
AO2 evaluation of MSM - Limitations -5 points to r
o It is reductionist, it OVERSIMPLIFIES memory structures and processes, unlike the working memory model. This is also apparent in case studies of patients with brain damage - if STM is necessary to transfer info, then LTM should also be affected.
o The model has been criticised for focusing too much on STRUCTURE and too little on PROCESS, unlike levels of processing
o There are problems with the research both METHOLOGICALLY and with CONTRASTING EVIDENCE
o It states Rehersal is the main cause for transferring info the LTM, however, in everyday life we rarely rehearse information. We usually remember something as it is interesting, and this is better explained with the Levels Of Processing theory
o Many of the studies supporting MSM are LAB studies and so, lack ecological validity and may have demand characteristics.