Memory Flashcards
The multi-store model of memory
− Three types of memory have been identified: the sensory register, short-term memory + long-term memory, these are generally considered to be memory structures or stores of information
− Sensory register – this is not under out control but is an automatic response to the reception of sensory information (input from our senses) + is the first storage system within the MSM, all memory must pass through the SR first, stores encoded sensory input
− Short-term memory – this is our present conscious experience where information is processed from the SR through attention + rehearsal, information is stored temporarily + it is thought to have limited capacity + duration, stores mainly acoustic or visual info
− Long-term memory – information can be stored permanently, it is thought to have unlimited duration + capacity if information has been processed sufficiently, the complexity of LMT has led to different types of memory being identifies e.g. semantic + procedural
The multi-store model of memory: Coding in the SR
− The SR processes sensory information received from the sense organs e.g. eyes, ears, nose
− Information is stored in a raw, unprocessed from with separate sensory stores from different sensory inputs:
→ Echoic store – auditory info e.g. music
→ Iconic store – visual info e.g. sunlight
→ Haptic store – tactile info e.g. pain
→ Olfactory store – smell e.g. cut grass
− Crowder found that the SR only retains info in the iconic store for a few milliseconds but for 2-3 secs within the echoic store which supports the idea of sensory info being coded into different sensory stores (it also suggests that they have different durations)
The multi-store model of memory: Capacity of the SR
− The capacity of each store in the SR is very large with information in highly detailed form
− The fact that the SR has such a short duration makes it difficult to research its capacity as the information leaves the store so quickly making it hard to find out how much was stored initially
The multi-store model of memory: Duration of the SR
− All sensory memory stores have limited duration although the duration varies from store to store with different types of information decaying at different rates
− Walsh + Thompson found that the iconic sensory store has an average duration of 500 milliseconds which decreases as individuals get older
− Evolutionary advantages of the brief duration of the SR – people can focus on perceptual information with an immediate survival value, retaining non-useful information would compromise this
The multi-store model of memory: Baddeley
− Procedure:
→ 75 ppts were divided into 4 groups + were presented with ¼ word lists (consisting of 10 words)
→ List A: Acoustically similar (cat, mat, sat)
→ List B: Acoustically dissimilar (pit, day, cow)
→ List C: Semantically similar (big, huge, tall)
→ List D: Semantically dissimilar (hot, safe, foul)
→ STM – ppts were then given a list containing the original words in the wrong order, their task was to rearrange the words in the correct order
→ LTM – the procedure was the same but there was a 20 min interval before recall during which ppts performed a distractor task to prevent rehearsal
− Findings:
→ STM – ppts given list A (acoustically similar) performed the worst with recall of only 10% they confuses similar sounding words e.g. cap instead of cat, recall for the other lists was comparatively good at bet. 60%-80%
→ LMT – ppts given list C (semantically similar) performed the worst with a recall of only 55% they confused similar meaning words e.g. big instead of huge, recall for the other lists was bet. 70%-85%
− Conclusions:
→ STM – Baddeley concluded that STM is encoded on an acoustic basis due to the acoustic confusion
→ LTM – Baddeley concluded that LTM is encoded on a semantic basis due to the semantic confusion
The multi-store model of memory: Coding in the STM
− Information arrives from the SR in its original form e.g. a sound or image + is then encoded (entered into STM) in a form that STM can more easily deal with
− Beddeley’s research suggests that encoding in STM is acoustic however other research has suggested information can also be encoded visually in STM
− Bradimonte et al found evidence to support this
→ They presented ppts with 6 line drawings of familiar objects + asked them to memorise each one
→ It is though that the drawings were encoded acoustically in terms of the objects name so when ppts were asked to form a mental image of the drawing + subtract a part of it to reveal a different object they were lea able to name the image than those ppts who were asked to memories that drawings whilst repeating the meaningless chant ‘la-la-la’ (which could have supressed acoustic encoding thus encouraging visual encoding of the information)
The multi-store model of memory: Capacity of STM
− Limited
− Miller’s ‘magic number 7’ – 7+/-2 items (5-9 items)
− Tested sing he serial digit span technique
− Capacity can be enhanced through chunking
The multi-store model of memory: Duration of STM
− Limited
− Less than 30 seconds
− Peterson + Peterson – ppts only recalled about 2% of trigrams when there was an 18 sec time interval compares to about 90% after a 3 sec interval
− Duration can be extended by rehearsal (repetition) of the information which is done long enough can result in the transfer of information to the LTM
The multi-store model of memory: Coding in the LTM
− Mainly semantic (by meaning)
− Baddeley – recall was worse for semantically similar worse than semantically dissimilar words but recall was the same for acoustically similar + acoustically dissimilar words suggesting the encoding is semantic due to semantic confusion
The multi-store model of memory: Capacity of LTM
− Potentially unlimited – information may be lost due to decay + interference but these losses do not occur due to lack of capacity in LTM
− Clive Wearing – demonstrated the existence of the procedural memory
→ :) Clive Wearing was unable to lay down any new long term memories after his hippocampus was destroyed by a viral infection suggesting that there is a separate short-term + long-term memory store in the brain
→ :( However Clive was still able to slight-read + play complex pieces on the piano suggesting that this procedural memory was intact which cannot be explained by the multi-store model of memory as it does not recognise different types of long-term stores
The multi-store model of memory: Duration of LTM
− Potentially a life time
− Items in LTM have a longer duration if originally well coded + certain LTMs seem to have a longer duration e.g. those based on skills rather than facts
− Material in STM needs to be rehearsed in order to be retained however information in LTM does not have to be continuality rehearsed to stay in the store
The multi-store model of memory: Barrack et al
− Procedure:
→ Investigators tracked down graduates from a high school in America over a 50 yr. period
→ 392 graduates were shown photos from their high school yearbook
→ Recognition group – for each photo ppts were given a group of names + asked to select the name that matched the photo
→ Recall group – ppts were simply asked to name the ppl in the photos without being given a list of possible names
− Findings:
→ In the name-matching (recognition) condition ppts were: 90% accurate after 14 yrs., 80% accurate after 25 yrs., 75% accurate after 34 yrs. + 60% accurate after 47 yrs.
→ In the recall group ppts were not as successful: 60% accurate after7 yrs. + less than 20% accurate after 47 yrs.
− Conclusion: Ppl can remember certain types of information for a life time, LTM appears to be better when measured by recognition tests than by recall tests
The multi-store model of memory: Research
− The serial position effect: Glanzer + Cunitz – ppts tended to recall the words from the beginning of a word list (primary effect) + from the end of the list (recency effect) rather than the middle
→ Primary effect – words at the beginning are rehearsed + transferred to LTM
→ Recency effect – these words remain in the STM prior to recall
→ This suggests that STM + LTM are separate stores
− Research has found that the prefrontal cortex is active when individuals are working on a task in immediate (i.e. short-term) memory (Beardsley) BUT the hippocampus is active when LTM is engaged (squire et al) – this further supports the idea that STM + LTM are separate stores in that it suggests they are located in different areas of the brain
− The case of H.M. supports + challenges the multi-store model of memory
→ The fact that H.M. was unable to form any new long term memories after the removal of his hippocampus suggests that there is a separate short-term + long-term store
→ However H.M. as able to acquire new skills suggesting that his procedural memory was intact – this cannot be explained by the multi-store model of memory as Atkinson + Shiffri view the LTM as a unitary store
Evaluation of the multi-store model of memory: Reductionist :(
− The model had been criticised for being too reductionist + inflexible to explain the entire memory system
→ It is reductionist because it reduces the complex nature of memory down to a simple set of ideas
→ It is an oversimplification of the memory structures + processes
→ E.g. it doesn’t explain the processes involved in encoding – there is too much emphasis on the structures eh SR, STM, LTM
→ It fails to recognise different types of long term memory e.g. procedural + episodic (as demonstrated by H.M. + Clive Wearing)
Evaluation of the multi-store model of memory: STM relied on LTM :(
− STM relies on LTM – this is not recognised by the model as it views the STM + LTM as independent stores, information may flow backwards from LTM
→ Ruchkin et al – STM is the party of the LTM that is activated when necessary
Evaluation of the multi-store model of memory: Rehearsal may not be the only way to commit memory to LTM :(
− Rehearsal may not be the only means by which to commit memories to the LTM
→ Information might be transferred to the LTM because of its distinctiveness or significance to the person (Eysenck)
→ Flashbulb memory – a highly detailed exceptionally vivid long-term memory of the moment + circumstance eh when you were, who you were with, during emotionally arousing or meaningful events (e.g. 9/11)
Evaluation of the multi-store model of memory: Case studies :(
− The case study of K.F. challenges the STM as a single (unitary) store as does the working memory model
− Evidence (H.M., Clive Wearing) has also suggested that there are different types of LTM e.g. declarative, episodic, procedural + that this isn’t a single store as the multi-store model would suggest
The working memory model
− Baddeley + Hitch proposed an alternative model to explain the short term memory
− They rejected Atkinson + Shiffrin’s ideas about STM being a unitary store – they argued that it was more complex than simply being a temporary store involved in transferring information to LTM
They saw STM as an active store – holding several pieces of information while they were being worked on
Central executive - episodic buffer - phonological loop/visuo-spatial sketchpad - LTM
The working memory model: Central executive
− The most important component
− It controls attention i.e. it receives information from the sense organs (e.g. ears + eyes) + decided what to attend to (i.e. filters incoming information)
− It plays a key role in directing information to + processing information from the ‘slave systems’ + LTM
− It is involved in problem solving + decision making
− It had a limited storage capacity so attention is limited at times – it can only effectively cope with one strand of information at a time
The working memory model: Phonological loop
− It has limited capacity
− It processes speech-based sounds for brief periods
− It consists of two parts:
→ Phonological/primary acoustic store (inner ear) – stores acoustically coded items e.g. words recently heard
→ Articulatory process (inner voice) – allows sub-vocal repetition (rehearsal) of items stored in the phonological store
The working memory model: Visuo-spatial sketchpad
− Stores/processes visual + spatial information (inner eye) + the relationship bet. them i.e. what items are+ where they are located
− It helps individuals to navigate around + interact with their environment
− It manipulated mental images
− It has a limited capacity
− Visual cache – stores information about form + colour
− Inner scribe – deals with spatial + movement information e.g. body movements + rehearses + transfers information in the visual cache to the central executive
The working memory model: Episodic buffer
− As addition storage system
− It binds together information from the different components into chucks/episodes including information from LTM e.g. recalling a scene from a movie (visual + verbal information)
− It has limited capacity BUT can potentially hold more than each of the two slave systems
The working memory model: The processing of visual + verbal tasks
− Baddeley proposed that because the STM consists of several different components that are able to work independently of one another that is therefore possible to complete a visual + verbal task simultaneously e.g. watching a film/TV which would tie up different slave systems
The working memory model research: Baddeley et al :)
− Baddeley et al
→ Procedure: ppts had to track a moving stop of light whilst either imagining the letter ‘F’ + classifying the angles (yes = include bottom/top line of letter, no = if it did not) or completing a verbal task – they therefore compared ppts doing two visual tasks against those doing a visual + verbal task
→ Findings: ppts found it more difficult to track the spot of light whilst classifying the angles of the letter ‘F’ because both tasks involved the visuo-spatial sketchpad which has a limited capacity – however those doing the visual + verbal task found it less difficult to complete both simultaneously because they involved both the VSS + PL therefore suggesting the VSS is a separate slave system
The working memory model research: Brain damage patients :)
→ KF – damage to phonological loop following a motorcycle accident led to difficulty processing auditory information BUT not visual information
→ LH – performed better on spatial then visual imagery tasks supporting the view that there are separate visual + spatial systems
→ They provided evidence for the existence of the two main slave systems as well as the sub-systems within the visuo-spatial sketchpad
→ :( The process of brain injury is traumatic which may in itself change behaviour causing a person to perform worse in certain tasks – this therefore makes it difficult to generalise the findings to others because of the unique characteristics of each individual (they lack population validity)
The working memory model research: PET scans
− PET scans show that different areas of the brain activated when doing verbal + visual tasks which suggests that the phonological loop + visuo-spatial sketchpad are separate store as reflected in the biology of the brain – PET scans have also shown activation in the left hemisphere of the brain with visual tasks + activation in the right hemisphere with spatial information which supports the existence of the visual cache + inner scribe
Evaluation of the working memory model: Benefits over the multi store model of memory :)
− One advantage of the WMM compared to the MSM is that it explains how it is easier to do two tasks that are different (e.g. verbal + visual – tested using the dual-task technique) than two tasks that are similar (e.g. two verbal tasks)
→ Each slave system had a limited capacity so there is only so much information they can process at any one time
→ Two similar tasks would place too many demands on the same slaves system thus making it more difficult to process the information resulting in a slower processing speed
Evaluation of the working memory model: The central executive is a vague concept :(
− Central executive – a vague concept
→ There are problems in specifying the precise function of the central executive – it isn’t clear what it is or how it works
→ Research into this component is lack despite it supposedly being the most important component
→ Critics dispute the idea of a single central executive +instead argue that there are probably several components
→ The central executive is perhaps better understood as a component controlling the focus of attention rather than a memory store like the PL + VSS
Evaluation of the working memory model: Only concerns STM :(
Working memory only concerns STM so it is not a comprehensive model of memory (as it does not include SM or LTM)
Types of LTM
− Just as the working memory model demonstrates different type of short-term memory research also indicates that existence of different types of long-term memory each with a different function + a different area of the brain associated with its use
Types of LTM: Episodic LTM
− This is the types of memory that provide us with an autobiographical record of our person experiences e.g. birthdays, wedding etc.
− The strength of episodic memories is influenced by the emotions present at the time a memory is coded e.g. traumatic events are often recalled well due to their high emotional content
− The strength of these memories is also influenced by the degree of processing of information at coding – highly processed episodic events are recalled more easily
− It is thought that this type of memory helps individuals to distinguish the difference bet. real + imagined events
− Episodic memories are associated with several areas of the brain:
→ The prefrontal cortex is associated with the initial coding of episodic memories
→ Consolidation (strengthening) of these memories is associated with the neocortex
→ Memories of different parts of an event are located in the different visual, auditory, olfactory etc. areas of the brain but are connected together in the hippocampus to create memory of an episodic rather than its remaining a collection of separate sensory memories
Types of LTM: Episodic LTM - Tulving
− Procedure:
→ 6 volunteers were injected with small amounts of radioactive gold + scanned to detect its location with a gamma ray detector
→ Each ppts performed 8 successive trails each lasting 80 secs, involving 4 semantic + 4 episodic topics in randomised order
→ Individual trails were separated by 2 mins of rest each – a ppts would lie face up on a couch with their eyes closed + indulge in either episodic or semantic LTM retrieval, the retrievals involved silent mental thought rather than physical stimulation or recording of behaviour, ppts decided what topics they would think about
→ At a signal from a researcher a ppts would start thinking about a topic
− Findings:
→ 3 ppts produced inconclusive data
→ Ppts showed consistent differences in cortical blood flow patterns bet. semantic + episodic thinking – there was greater activation in the frontal lobes activation in the frontal lobes of the cortex during thinking about episodic memories + greater activation in the presterior region when retrieving semantic information
− Conclusion:
→ Episodic + semantic LTMs appear to involve different brain areas + thus are separate forms of LTM
→ The fact that episodic + sematic memories involves different brain areas suggests a biological bias to difference in LTM
Evaluation of Episodic LTM (types of LTM): Unclear difference bet. episodic + semantic LTM :(
P: The extent to which episodic + semantic memory systems differ in unclear – although different brain areas are involved there is also a lot of overlap bet. the two systems
E: Semantic memories often clearly originate in episodic memory (e.g. your memory of being taught something is episodic but what you learn may be semantic)
C: It may be the case that an episodic memory can transform into a semantic memory however we cannot be certain whether this is what occurs
Evaluation of Episodic LTM (types of LTM): Scientific techniques :)
Research often uses advanced scientific techniques e.g. brain scans which are objective therefore increasing the reliability