Memory Flashcards
Define memory
The mental process used to encode, store and retrieve information. It is useful to distinguish between 2 types of memory- STM and LTM.
What is capacity
The amount of information that can be held in a memory store
What is the capacity of STM
7 +/- 2 units
What is the capacity of LTM
Impossible to test- unlimited
Which researchers investigated the capacity of STM
Jacobs (1887) and Miller (1956)
Describe the work of Jacobs on STM
Digit Span Technique:
- Laboratory experiment
- Ask Pp to remember and repeat lists of items in increasing length
- Pp had to recall lists of digits or letters in the same order they were presented- serial recall
- Pace matched to a metronome
Describe the findings/conclusions of Jacobs on STM
- average STM span was between 5 and 9 digits
- Digits recalled better than letters (9.3 items vs 7.3)
- digit span increased with age- 6.6 for 8-year-old children and 8.6 for 19-year-olds
- Capacity of STM is 7 +/- 2 units
- individual differences such as age increase digit span
Describe the work and findings of Miller on STM
- the amount of info STM can hold can be increased by chunking- organising items of information into groups to make most of STM
What are the limitations of research on the capacity of STM, include a counterargument
- Lab study- lacks ecological validity- artificial setting
- lacks mundane realism- not something we would do in everyday life
- Jacobs is an old study- could have been confounding variables distraction- however, findings confirmed by well-controlled studies later - repeatable- Eg. Bopp and Verhaegan 2005)
- Cowan (2001) reviewed other research and concluded STM capacity is only about 4 +/- 1 chunk- lower end more accurate?
Who investigated the duration of STM
Brown; Peterson and Peterson
What were the aims of Brown; Peterson and Petersons experiment
- To investigate the duration of STM and effects of rehearsal
- Used the Brown-Peterson technique- a method of measuring STM while reducing rehearsal
What was the procedure for Brown; Peterson and Petersons study
- PPs briefly shown a trigram of consonants, eg. VGT, FCN
- Then asked to count backwards in 3s from a given number
- after intervals of 3,6,9,12,15 or 18 seconds, participants were asked to recall trigram
What were the findings from Brown; Peterson and Petersons study
- PPs able to recall 80% of trigrams after 3-second interval
- 50% after 6 seconds
After 18 seconds dropped to under 10%
What were the conclusions from Brown; Peterson and Petersons study
- Info in STM is lost quickly if rehearsal is prevented
- Became known as Brown-Peterson effect- the rapid loss of info in STM if rehearsal is prevented
Explain 3 positives from Brown; Peterson and Petersons study
- Important practical applications- improve peoples memory from rehearsal- findings can be used to improve lives
- Adds support to their of two memory stores- as counting backwards prevents rehearsal and passing to LTM store- research important contribution to our understanding of memory
- Highly controlled- studies carried out in labs so extraneous variables controlled- reliable and valid
Explain limitations of Brown; Peterson and Petersons study
- Lacks ecological validity- lab study- cant generalise results to other situations
- Lacks mundane realism- not something you’d do in everyday life- lacks external validity
Who investigated the duration of LTM
Bahrick et al (1975)
What was the aim of Bahrick et al study
- measure duration of LTM
- Demonstrate the existence of very long term memory
- Testing memory of real-life information
What was the procedure of Bahrick et al study
-40- student Pp of different ages Using old school yearbook, Pp asked to: - Free recall of classmates - photo recognition - name recognition - name and photo matching
What was the findings of Bahrick et al study
- After up to 34 years, Pp could remember up to 90%
- After 48 years declined to 70%
- free recall less accurate- 60% after 15 years, 30% after 48 years
What was the conclusions of Bahrick et al study
- LTM has potential to last a lifetime
- People have very long term memories that are very accurate
What were the positives from Bahrick et als study
- good mundane realism- the recall of peoples names and faces something we do in everyday life- makes it possible to generalise findings to other situations- when meaningless recall results lower- eg. Shepard 1967
- adds support to the theory of 2 memory stores- people recalling the names from LTM which appears to have a long duration- good understanding of how human memory works
- highly controlled- lab setting- researcher could control variables- findings more likely to be reliable and valid
Define coding
- The way in which memory is changed and formatted to be stored in the various different memory stores
Who investigated coding
Baddeley (1966)
What was the aim of Baddelys investigation
To explore the effect of acoustic and semantic coding in STM and LTM
What was the procedure of Baddelys investigation
In STM study, Pp asked to immediately recall in serial order a list of 5 words taken from the following categories:
- acoustically similar
- acoustically different
- Semantically similar
- Semantically dissimilar
In LTM study each list extended to 10 and recall was tested after 20 mins
What were the findings of Baddelys investigation
- in STM acoustically similar harder than dissimilar, but semantics had little effect
- in LTM, recall of semantically similar words much worse than dissimilar, acoustics little effect
What were the conclusions of Baddelys investigation
- STM relies on acoustic coding
- LTM relies on semantic coding
Evaluate Baddelys study
- 20 mins- may not have been effectively testing LTM
- STM may not be exclusively acoustic- when Pp had visual task to complete an verbal rehearsal prevented, Pps were able to use visual codes to recall info (Brandimote et al 1992)
- meaningless stimuli- lacks mudane realism- not much learnt about coding for memory tasks in everyday life- eg. might actually use semantic STM
- However did identify clear difference between 2 memory stores- acoustic vs semnatic repeatable- helped lead to Multi store model of memory
what is the duration of STM
18-30 secs
What did Atkinson and Shiffrin (1968) conclude
Memory is made up of a series of stores and can be described memory as information flowing through a linear system. It can be described as an information processing model, with input, processing ad output.
Describe the transfers and stores of the multistore model of memory
Input –> SENSORY REGISTER
- -Attention/transfer–> STM
- -rehearsal (maintenance loop to keep, prolonged to transfer)–> LTM
- -retrieval–> STM
- -Response–> leave (remembering)
What is the capacity, duration and coding of the sensory register
- unlimited
- 250 milliseconds
- Modality specific
What is the capacity, duration and coding of STM
- 7 +/- 2 units
- 18- 30 secs
- Acoustic
What is the capacity, duration and coding of LTM
- Unlimited
- potential for lifetime
- semantic
Define the multi-store model of memory
A representation of how memory works in terms of 3 stores- sensory register, STM and LTM. Also describes how info is transferred from one store to another, what makes some memories and some disappear
Describe the use and coding of the sensory register
- all stimuli from the environment pass into the sensory register
- composes of several registers- one for each of the 5 senses
Modality specific coding- eg. visual = iconic memory, sound = echoic-n others for touch, taste and smell
Describe maintenance rehearsal
Occurs when we repeat material to ourselves over and over again- we can keep info in our STM if we repeat it over and over if long enough, transferred to LTM
What is elaborative rehearsal
Involves more meaningful analysis, (eg. images, thinking, associations) of info and leads to better recall- eg. giving words meaning or linking with previous knowledge.
Who studies the sensory memory for vision
Sperling (1960)
Describe Sperlings Studies
- studied the iconic store in sensory memory using a tachistoscope- can flash pictoral stimuli onto a blank screen for very brief instances
- Asked Pp to remember as many letters as they could from grid of 12 symbols displayed for 50 ms
- could only recall around 4 before grid faded from sensory memory, but reported seeing more than had time to report
How did Sperling use his study to measure capacity
- devised partial report technique
- trained Pps to distinguish between 3 tones- high, medium or low tone
- then exposed grid for same amount of time, when disappeared a tone corresponded to row of 4 letters- top high tone etc
- In the partial report condition, recall was on average just over 3 out of 4 symbols from any row
- suggests iconic store can retain approximately 76% of all data recieved
How did Sperling use his study to measure duration
If there was a delay between the presentation of the grid and tone, more and more info was lost- only 50% available after 0.3 sec delay, only 33% after 1 sec
What is an example of research to support the MSM
Glanzer & Cunitz
What was the procedure and findings of Glanzer & Cunitz
Procedure:
- Pp presented with list of words and asked to immediately recall
Findings:
- Words at beginning of list are recalled (primacy effects)
- Words at end of list also recalled (recency effect)
- Words in middle forgotten (asymtote)
Explain the findings of Glanzer & Cunitz in terms of the MSM
- pay attention ar first - SR-STM- and have a chance to rehearse -LTM
- by middle, capacity slots in STM filled- can’t remember any more without time to rehearse previous
- at end, still in STM
Evaluate the MSM
Strengths: -research indicates differnce between STM and LTM- different in terms of capacity, duration and encoding- 7+- 2 units vs unlimited (Jacobs)- empirical support for muti stire model adding wider academic credibility, however studies differentiating lack mundane realism- we recall names, faces, stories etc all the time- studies used things with no meaning- not applicable to real life?
Case of HM
Weakness- Model is too simplistic in that other models of both STM and LTM propose that both STM and LTM may be provided in to a number of different stores- working memory model (Baddeley and Hitch 1974) suggests STM more accurately represented using series of different stores which handle different modalities (acoustic and visual), Tulving (1985) suggests LTM divided into episodic, semantic and procedural memory- MSM doesn’t provide complete explanation
Cases of KF and Clive Wearing
Describe the case study of HM
Henry Molasion
- very severe epileptic
- brain surgeon removed hippocampi to try and control seizures- controlled epilepsy but left him with severe memory impairment
- global amnesia for new material- lost ability to form any new LTMs- names, songs, places
- still remembered things before the surgery
- however could learn new motor skills- tracing star in mirror improve, using a walking frame- however subconscious level
Relate the case study of HM to the MSM
- supports 2 types of memory- has STM but no LTM- shows different duration, capacities etc
- however, shows simplistic- shows different procedural vs episodic LTM- MSM doesn’t account for motor memory
Describe the case study of Clive Wearing
- Viral encephalitis affected the hippocampus
- lost all LTM- only has STM- sees only what’s in front of him then forgets
relate Clive Wearing to the MSM
- for- 2 separate stores
- against- can still play music, sing an conduct- procedural memory still intact
Describe the case study of KF
Shallice and Warrington (1970)
- difficulties processing verbal information, but normal ability to process visual information- amnesia- couldn’t recall digits when read out loud, but could when read himself