The multi-store model of memory Flashcards
Types of memory
Short term memory- limited capacity memory store.
Long term memory- Permanent memory store.
Characteristics of memory
Capacity- how much information it holds.
Duration- how long information is held there.
Coding- how the information is processed and stored.
Capacity of STM
- Jacobs (1887) - measured digit span by given ppts a series of numbers to remember.
- Findings- adult STM capacity is 9.3 for digits and 7.3 for letters.
- Miller (1956) - the ‘magic’ number 7 +/- 2.
- We can improve the capacity of our STM.
- Chunking allows the STM to increase it’s capacity eg. shopping lists placed into categories.
Duration of STM
- Peterson and Peterson (1959) - used trigrams to illustrate how short the STM really is.
- Each ppt took part in 8 trials. Each trial involved them stopping counting backwards in 3’s, after a different number of seconds.
- Findings: suggested that the longer the interval between seeing the trigram and recalling it decreases the amount of correct responses.
(after three seconds -> 80%, after 18 seconds -> 15%) - Duration of STM is 0-18 seconds
Duration of LTM
- Bahrick (1975) - used 392 American ppts and their high school yearbooks. Ppts were aged between 17-74.
Photo recognition: 90% accurate after 15 years, 70% accurate after 48 years.
Free Recall: 60% accurate after 15 years, 30% accurate after 48 years. - suggests free recall is weaker than photo recognition, as accuracy is higher for both age groups. Accuracy of LTM declines over time. Tells us the duration is generally 30 years +, with prompting supporting LTM.
- the duration is a lifetime but the ability to recall all the info. accurately is not.
Strengths of Bahrick’s research
- High mundane realism:
- realistic study- yearbooks.
- high external validity- applies beyond research.
- compared to Jacobs, Peterson & Peterson. - Easily replicable:
- all US graduates have yearbooks
- allows accuracy of conclusions to be verified. - Quantitative data (can be used for other studies)
- % accuracy of recall and recognition.
- easy to analyse and form a conclusion.
Weaknesses of Bahrick’s research
- Biased research:
- Only Americans
- results cannot be generalised beyond the US. - Ppt variables (individual differences):
- social status in school/ friendship groups/ staying in touch.
- less accurate results (extraneous variables)
Research for coding
- Baddeley (1966)- got groups to remember words in 4 categories.
Acoustically similar: Cat, Cab, Canter
Acoustically dissimilar: Pit, Few, Deliver
Semantically similar: Great, Large, Ginormous
Semantically dissimilar: Excellent, Koala, Help - Findings: Acoustically similar words were worst recalled in short term- STM encodes info acoustically. Semantically similar words worst recalled in long term- LTM encodes semantically.
- Indicated by poorer recall = confusion in that sensory modality.
MSM: Outline the multi-store memory model (6 marks)
The multi-store memory model outlines the systems of memory in the human brain. The first, sensory registers, receives sensory information from a stimulus in the environment. This is a huge, short term store that processes this information either in iconic or echoic memory. The duration is less than half a second, but the capacity is huge when given attention. The STM is the next component where it received processed information from sensory registers; the duration isn’t very long (18-30 seconds) but through maintenance rehearsal information can enter the STM and through prolonged rehearsal can enter the LTM. LTM retains information forever but requires retrieval to be recalled by the STM. LTM info must be consciously retrieved, moved to STM and remembered by responding.
The case of HM
Underwent experimental neurosurgery to control seizures, resulted in extreme memory loss.
Supports the multi-store model as information could not be transferred from his STM to LTM as he cannot retrieve info. but passed a test for STM.
Structure of Multi-store memory model
Stimulus from the environment passes through sensory registers.
->
STM- limited capacity.
Response (remembering) Maintenance rehearsal (rehearsal loop)
->
Prolonged rehearsal -> LTM- permanent memory store.
LTM-STM= retrieval
Sensory register
- Stimulus from the environment will pass into sensory registers (senses).
- This part of memory is not one store but several- one for each of our senses.
- Main stores:
1. Iconic memory- visual info. coded visually.
2. Echoic memory- sound info. coded acoustically. - Info lasts briefly- duration is less than half a second.
- High capacity eg. over one hundred million cells in one eye, each storing data.
- Very little passes from this further into memory system- will if you pay attention to it (attention= key process)
STM
- known as limited capacity store because it can only contain a certain number of ‘things’.
- capacity on average between 5 and 9 items.
- info in STM is coded acoustically and lasts about 30 secs unless rehearsed.
- Maintenance rehearsal occurs when we rehearse material over and over.
LTM
- permanent memory store for info that’s been rehearsed for a prolonged time.
- Bahrick (1975) found many ppts could recognise names and faces of classmates 50 years after graduating.
- LTM tends to be coded semantically.
- Although material stored in LTM for a lifetime we have to use retrieval to transfer it back to the STM to recall it.
AO3: Challenging Research
- says there is more than one type of rehearsal.
- MSM says rehearsal is about the amount that you do. More you rehearse, more likely you are to transfer it to LTM.
- Craik and Watkins (1973) found type of rehearsal to be more important.
- discovered maintenance rehearsal that doesn’t transfer info to LTM.
- elaborative rehearsal required for long term storage- happens when you link to existing knowledge or meaning.
- research finding that cannot be explained by the model.
