Memory The multi-store model of memory. Specification topics covered: The multi-store model of memory: sensory, register, short-term memory and long-term memory. Features of each store: coding, capacity and duration. The specification -The multi-store model of memory: sensory register, short-term and longterm memory. -Types of long-term memory: episodic, semantic and procedural. -The working memory model: central executive, phonological loop, visuospatial sketchpad and episodic buffer. Features of the model: coding and capacity. -Explanations for forgetting: proactive and retroactive interference and retrieval failure due to absence of cues. -Factors affecting the accuracy of eyewitness testimony: misleading information, including leading questions, post-event discussion and anxiety. -Improving the accuracy of eyewitness testimony, including the use of the cognitive interview. Making links with the specification… -The multi-store model of memory: sensory register, short-term and long-term memory. All of our senses have a sensory store, but for the MSM the sensory store focuses on two main stores, the iconic and echoic. The iconic refers to visual imagery and the echoic refers to auditory information. Iconic information is encoded visually and echoic information is encoded acoustically. Information in the sensory register is very brief, the duration is very limited, less than half a second and it has a very limited capacity. For information to reach our STM we must pay attention to it. Information is held within the store through maintenance rehearsal and transfers to the LTM by elaborative rehearsal. The STM has a capacity of 7+/-2 and a duration of approximately 30 seconds. Information is usually encoded acoustically. Information usually enters our LTM from the STM via elaborative rehearsal. The duration and capacity for the LTM is potentially unlimited. Information is usually encoded semantically. Experiment You will see a list of words, you will have thirty seconds to remember the word list. You are instructed to remember the words through your use of memory, do not use any other means (e.g. writing the words down). Words must be recalled in the correct order. Tap Tan Tar Cap Map Bar Rap Ban Ran Lan Car Far You have thirty seconds to write down as many words as you can remember. Hit Lab Tin Pot Pan Lip See Now Pop Bow Mum Lap You have thirty seconds to write down as many words as you can remember. Coding refers to the format in which information is stored in a memory store (e.g. acoustic). Research on encoding Evaluation Baddeley and Baddeley (1966a, 1966b) Participants were grouped into four different groups and given different lists of words to remember. Participants were in the following groups 1) Acoustically similar words (e.g. cap, cat, can). The stimuli used in Baddeley’s research could be argued to be artificial as the word lists have no meaning to the participants. 2) Acoustically dissimilar words (e.g. pit, few, cow). 3) Semantically similar words (e.g. great, large, big). Participants were asked to recall words in the correct order. When participants recalled the words immediately their recall was less accurate for acoustically similar words. This suggests that the STM codes information acoustically. Also the task itself lacks mundane realism, it is not often we are required to participate in such tasks. Therefore we must hold caution when attempting to generalise the findings to other types of memory tasks. When participants were required to recall information after a time period of 20 minutes (testing LTM recall) accuracy was lower for semantically similar words, suggesting information is coded semantically in the LTM. It has been found that people may still use semantic coding for STM tasks. 4)Semantically dissimilar words (e.g. good, huge, hot). If participants struggle with a specific type of word on immediate recall, they may well be confusing words for others or even recalling words which were not they. This confusion suggests we code information in the specific way. Consider immediately recalling cap, cat and can; there is a significant chance of recalling the word cab or cam (or something similar). Consider recalling the following words great, large and big after a twenty minute interval; there is a significant chance of recalling other semantically related words such as huge or vast. You need to write down the digits in the correct order in which they are presented. XTYN NBWDS LDTNCS ZPAKFRW KSOEMALX RMSKQPSAL XIWKAMXALO SOENVMALQDF LDPQEMCNANGJ Capacity refers to the amount of information which can be held in a memory store. Research on capacity Evaluation Jacobs (1987) used the digit span technique to measure participants capacity in their STM. Participants are given a sequence of digits and are required to recall these out loud in the correct order. Each time the participant correctly recalls all digits it increases by 1 digit. The maximum number of digits a participant is able to recall is their digit span. Jacobs found that the mean span for items was 9.3 and letter 7.3 Jacob’s study has been challenged on its validity as there was a suggested lack of control. However, further studies have confirmed Jacob’s findings lending support to its validity. Miller (1956) suggests that the capacity for short term memory is 7 +/- 2 (roughly between 5-9 items). Miller suggests we can chunk information (organise it into a more meaningful construct). For example consider the following two sequences of letters Miller has been challenged on his suggested capacity by Conway (2001) who reviewed other research and concluded the capacity of memory was only four chunks. A R Y S C D W N J I Y L B T E C G C S E G N V Q The second sequence is easier to remember we can chunk the letters into three chunks BTEC GCSE GNVQ You will be presented with a trigram, once the trigram has disappeared you need to count aloud backwards in threes from the number you see on the screen. VQL 297 Write down the trigram on your paper. LQU 234 Write down the trigram on your paper. IXV 252 Write down the trigram on your paper. Duration refers to how long information can be held in a memory store. Evaluation Peterson and Peterson (1959) measured duration by having participants remember a trigram (a three letter nonsense word such as DVW) and a three digit number. Participants were asked to count backwards from their three digit number in threes until told to stop. The reason for counting back was to prevent rehearsal, when we engage our mind with another mental process it prevents us actively rehearsing internally (which may improve duration). Participants completed 8 trials and the total time they had to count backwards for varied and increased over each trial. As is evident from the graph, after an 18 second interval almost all participants were unable to recall the trigram, suggesting the duration of the STM is approximately 18 seconds. Bahrick (1975) tested participants LTM recall of former class members. This was done in a number of ways which included a photo recognition test and free recall test. Participants tested 15 years after graduation were 90% accurate in their photo recognition and 60% accurate in their free recall. Participants tested after 48 years after graduation were 70% accurate in their photo recognition and 30% in their free recall. These findings suggest that the LTM can be potentially unlimited. The stimuli used in the study by Peterson and Peterson can be challenged on the stimuli used. It is not a usual task to perform in everyday life, therefore we may challenge the generalisability of their findings to everyday situations (thus challenging the external validity of their research). The stimuli used in Bahrick’s study was high in external validity. The stimuli used was personal to participants and accurately measured their LTM recollection of an event personal to them. However, due to the nature of the study other factors were not controlled which may have affected findings, such as when participants last looked at their yearbook folders etc. All studies described so far which support the MSM can effectively be used as evaluation as long as they are shaped. Jacobs (1887) Miller (1956) Baddeley and Baddeley (1966a, 1966b) Peterson and Peterson (1959) Bahrick (1975) Do we really only have one STM? Brain scans The MSM suggest we have one STM, however, a research study concerning KF (Shallice and Warrington, 1970) suggests we have we may have more than one STM store. KF suffered amnesia, his memory for digits was poor when they were read aloud to him but memory improved when he was able to read them himself. This suggests there may be another STM for verbal sounds. Beardsley (1997) found the prefrontal cortex was activated during STM but not LTM tasks and Squire et al. (1992) found the hippocampus activated during LTM. Suggesting different stores use different parts of the brain, thus supporting the MSM’s claim we have separate stores. The MSM is too simple Type of processing and rehearsal. All studies support one of more aspects of the multi-store model of memory. You can also use evaluations of studies in relation to the MSM, again these must be shaped to relate to the question you are answering, More than one type of LTM? We have different types of LTM (see types of LTM Tulving, 1985) for example we learn to walk and navigate, it has been suggested this is a different type of LTM to factual knowledge, something not explained by the MSM. Craik and Lockhart (1968) found that we are likely to remember information more when we process it semantically rather than acoustically or structurally, they sagest for us to remember something we need to process it a specific way rather than simply rehearsing it. Craic and Watkins (1973) suggest that rather than merely rehearsing information (thus transferring it to our LTM) we need to link it with existing knowledge, known as elaborative rehearsal. One big criticism is that the MSM is considered too simple to give an effective account of memory. As has been suggested the STM and LTM are far more complex than two simple unitary stores. Logie (1999) suggests that the STM comes first in the MSM but actually relies on the LTM to process information This may be commented on as an evaluation point in your answer.