Memory psych

• Describe the multistore model of memory. (Atkinson & Shiffrin)

  - It explains how information flows through a series of storage systems, 3 permanent structures, SR, STM, LTM.

  - Each stage differs in terms of Capacity, how much info can be stored, Duration, how long information can be stored for, Coding, the form that information is stored in.
• What is stored in the sesnsory register?


  Information take in by our five senses is automatically stored in an unprocessed form in the SR.
• Which two stores are most studied in the SR?

  - The iconic store (visual info)

  - The echoic store (auditory info)
• Coding, Capacity and Duration in SR

  Coding: raw info is stored in different senses

  
  

  Capacity: Large and, can temporarily store all sensory info that we take in through senses. It is the amount of information stored in the different parts of memory

  
  

  Duration: approx. 250 milliseconds, although it varies between the 5 stores. It is the length of time the information is held in the memory for.
• Evaluation - Evidence for the SR.

  - Sperling, large capacity, he flashed a 3x4 grid of letters onto a screen for 1/20th of a second, and immediately sounded one of 3 different tones indicating which of the rows of letters the ppts. were to recall. Recall = consistently accurate.
• Coding in STM


  Baddeley...

  - Aim, to see whether coding in stm is acoustic or semantic

  - Procedure, 4 groups, each group heard a different set of words. A, acoustically similar. B, acoustically dissimilar. C, semantically similar. D, semantically dissimilar.

  - Findings, A = 10% accuracy. B, C & D = 60%-80% accuracy.

  - Conclusion, STM is primarily acoustic, A recall is significantly lower.

  - Evaluation, stm is mainly acoustic, some semantic coding, some visual coding.
• What did Posner and Keele find?

  Ppts. were faster to asses that two letters were the same when A was followed by A than when A was followed by a.
• Capacity of STM, Jacobs

  Aim, test the capacity of STM using the serial digit span method

  Procedure, ppts. were read a list of one syllable letters or digits to listen to and repeat immediately in the right order. The lists increased making the task harder. The list length at which a ppt. could only recall the list in the correct order 50% of the time was defined as their capacity or ids.
• Findings by Jacobs


  The capacity for numbers was 9 items and for letters 7 times.
• Jacob's conclusions


  - Limited capacity in STM.
• Miller


  Most people have a recall of 7+_2. Millers magic number. 'Chunking digigt' increases the number of digits recalled.
• Capacity of STM evaluation

  - age & practice can influence the capacity, the main limitation is due to processing limitations associated with attention.
• Duration of STM, Peterson&Peterson

  Aim, investigate duration of stm

  Procedure, trigrams, BDJ, and asked them to count backwards in 3s from a large 3 digit number for different amounts of time, then recall the trigram. Counting backwards is a distracter task.
• Findings of P&P


  approx 90% of trigrams were recalled correctly after 3 seconds of counting, fewer than 5% being recalled after 18 seconds of counting.
• P&P Evaluation


  - Flawed methodology due to variation in trigrams used in each trial may have caused interference between items, reducing recall

  - Nonsense trigrams lack mundane realism

  - Marsh et al, if ppts. weren't expecting to recall info the duration of stm was only 2-4 seconds. Suggests duration in stm by the amount of time taken to process.
• Define rehearsal


  Simply repetition of info, either aloud, or sub-vocal. If info in stm is rehearsed then that info will be maintained there. If it is sufficiently rehearsed or elaborate it will be coded into the LTM.
• Coding in LTM, Baddeley Procedure

  Same as the experiment into the coding in STM, except a 20 minute interval before the ppts. were asked to recall the words. Plus a distractor task.
• Coding in LTM findings

  C, 55% accuracy

  A, B & D, 70%-85% accuracy
• Coding in ltm conclusion

  Coding in ltm is mainly semantic rather than acoustic, as the meaning of the words had the greatest effect on the accuracy of recall.
• Evaluation of Coding in LTM

  - semantic coding for verbal material,

  - Frost gave ppts. 16 drawings in 4 catagories, differing in visual orientation. The order of recall items suggested some visual coding in LTM
• Capacity of LTM


  Seems to be limitless!!!!
• Evaluation of Capacity of LTM

  - Only limitless because research has not been able to determine a finite capacity

  - Limited capacity of LTM has been demonstrated in other species, evolutionary basis for our 'limitless' LTM

  - E.g. Fagot and Cooke, pigeons can memorise 1,200 picture response associations, while baboons still hadn't reached their capacity after three years of training, memorising 5,000 associations.
• Duration of LTM, Bahrick et al


  Aim, investigate duration of ltm

  Procedure, 400 ppts. aged between 17 and 74 were given several tasks requiring them to recall people that they were in their final year of high school with. Free recall and from pictures. Compared ppts. who had left high school in the last 15 years/48 years.
• Duration of LTM Findings

  Ppts within 15 years of graduation were about 90% accurate in identifying names and faces, but only 60% accurate in the free recall task.

  PPts who had graduated 48 years ago or longer were 70-80% accurate on the recognition tasks but only 30% accurate in the free recall task
• Conclusion Bahrick et al


  Memory for most people is long-lasting, potentially a life time.

  Sometimes a trigger is needed in order to access them
• Evaluation of LTM


  Appears tp be lost, but just a problem with accessing, B et al better in recognition tasks than face recall
• MSM EVALUATION


  Murdock, separate STM and LTM

  Procedure, list 10-40 words and free recall. Each word was presented for one to two seconds

  - He found that recalling any word depends on its position in the list. Words presented wither early in the list or at the end were more often recalled. Ones in the middle were more often forgotten. The serial position effect.

  - beginning = primacy effect, end of list = recency effect.
• Murdock conclusions


  - he suggested that early in the list were out into LTM because the person has time to rehearse each word acoustically.

  - Words from the end went into STM, about 7 items.

  - Words in the middle of the list had been there too long to be held in STM (due to displacement), and not long enough to be put into LTM.
• Criticisms of the MSM

  - the model focuses too much on the structures and doesn't explain the processes involved in enough detail.

  - Also the model suggests info only enters LTM through rehearsal.
• The working memory model


  (Logie) Visuo spatial scatchpad should be divided into, the visual cache, the inner scribe.

  The phonological loop is divided into, the primary acoustic store, the articulatory process

  Each component has a limited capacity

  
• What is the central executive?


  - determines which info received from the sense organs is and isn't attended to.

  - no storage capacity, limited processing capacity, only cope with one strand of info at a time

  - CE is selective in order to create a balance between tasks, allows us to switch attention from one input of info to another
• Explain the role of the phonological loop.

  - deals with auditory info, order of info.

  - subdivided into the primary acoustic store and the articulatory process. PAS = stores words recently heard and the AP keeps info in the PL through sub-vocal repetition, linked to speech production

  - similar to rehearsal system of the msm, limited capacity.
• VSS


  - a temporary store for visual and spatial items, and info about the relationship between them

  - helps us find our way around, interact with physical environment

  - info is coded and rehearsed through the use of mental pictures

  - Logie suggests a visual cache (form and colour) and inner scribe (spatial relationships)

  - VSS rehearses and transfers info in the visual cache to the CE
• Episodic buffer (added by Baddeley in 2000)

  - temporarily stores info combined together form the CE, the PL, the VSS and LTM.

  - since the PL and the VSS have limited capacity and the CE has no storage capacity.
• Evaluation of the WMM

  Dual-task studies:

  Baddeley, ppts. struggled to carry out two simultaneous and complex tasks. Supports the suggestion that the CE has limited capacity and so can only cope with one task at a time.

  Brain scanning studies:

  fMRI scans, pre-frontal cortex activated when verbal and spatial tasks performed simultaneously than a visual and a spatial tasks. Supports a separate visual chache and inner scribe within the VSS.
• Criticisms of the WMM

  - lacks sufficient detail on how the CE works and what exactly the capacity of each individual component is, and so isn't possible to disprove it with research evidence.

  - dual task studies lack realism as they are not like the sort of processing our wmm does in everyday life
• What is the episodic LTM?

  - a type of explicit or declarative memory

  - an autobiographical record of personal experiences

  - a strength of these mems. is influenced by emotions associated with the experience and the degree of processing at coding

  - they may help us distinguish between real and imagined events
• What is the Semantic LTM?


  - a type of explicit or declarative memory

  - contains all the knowledge we have learned

  - the strength of these mems. is influenced by the degree of processing at coding

  - Episodic underpins semantic as new knowledge tends to be learned from experiences. Over time there is a gradual shift from e. to s. as the knowledge becomes increasingly divorced from the event or experience it was learned from
• What is Procedural LTM?

  - a type of implicit or non-declarative memory

  - allows us to perform learned tasks with little conscious thought. Also, people can simultaneously use procedural memory & perform other cognitive tasks that require attention

  - most memories occur in early life and involve motor skills

  - P. and s. memories often work together, e.g. in forming sentences in a language
• Give research evidence for separate declarative and non-declarative (procedural) LTM

  - Case study of HM (Milner)

  - He suffered from anterograde amnesia, as his hippocampus was removed to treat epileptic seizures, Milner demonstrated that he could gain new procedural LTM although he was unaware of it