Memory Flashcards
What is memory and what are the three processes in it?
Memory is the process of retaining learned info and accessing it when needed
Processes:
1. Coding - way info is changed so it can be stored in memory
2. Storage - keeping info within memory system until it is needed
3. Retrieval - recovering information stored in the memory system when it is required
What are the three memory stores?
Sensory register - contains unprocessed info received from senses (has separate stores, iconic store for visual and echoic store for auditory info)
STM- temporary store of info received from SR
LTM - permanent store holding limitless amount of info for a long time
What is capacity and duration?
Capacity - amount info that can be held in memory before new info displaces it
Duration - amount of time info held in memory store before it’s lost due to decay
How did Baddeley investigate coding in STM and LTM and evaluate the study?
STM - Baddeley (1966) gave pps 4 list of words to recall. A had similar sounding words, B had dissimilar sounding words, C had words with similar meanings and D didn’t. He argued STM is coded acoustically (how it sounds) as when tested pps performed worst with A than B, with no difference between C and D
LTM - repeated the experiment and tested pps recall after 20 mins to ensure info passed into LTM. Recall of C worse than D with no difference between A and B. Suggests LTM coded semantically (meaning)
Lab experiment so easy to replicate since controlled variables+ high reliability but has low ecological validity (words recalled artificial and would never happened IRL)
Study investigating capacity of STM (Jacobs)
Jacobs (1887) used digit span test, giving pps diff sequences of digits and letters and asked them to repeat each one straight after he gave it
Sequences got longer by one each time and he found span of STM is 7+-2 pieces of info. More than that means info is displaced.
+STM capacity increases with age
Study was a long time ago so validity has to be questioned
Repeated measures design - order effects
What is the capacity of SR and LTM
Unlimited
Duration of SR
250 milliseconds
Study investigating STM duration (Peterson and Peterson)
1959 Peterson x2 used nonsense trigrams (random 3 consonants) to test duration
- prevent pps from keeping info in stm using maintenance rehearsal pps were asked to count backwards from 100 in 3s
- after 3 seconds recall 90% accuracy
- after 9 seconds 20% accuracy
- after 18 seconds 2% accuracy
STM lasts 18-30 secs before decay happens
Good study as extraneous variables removed and there was a high level of control, standardised procedures used (noise and other factors limited)
Lack of mundane realism as it used artificial material which people don’t remember irl
The findings of this study may have been caused by interference rather than
by STM having a short duration. It is possible that earlier learnt trigrams
became confused with later ones.
Study of LTMs duration (bahrick)
Bahrick (1979) tested 400 pps of various ages on memory of classmates by showing them 50 people and asking if they were classmates or not
90% accuracy within 15 yrs
48 yrs 70% accuracy
Asked to recall names of classmates asw
Within 15 yrs 60% accurate, 30% after 48 yrs
LTM lasts a lifetime but have retrieval failure and need retrieval cues
High ecological validity but hard to control extraneous variables like keeping in touch
Independent groups design - pps variables can have an effect
What is the multi-store model of memory
The multi-store model of memory (MSM) was developed by Atkinson and Shiffrin (1968). It attempts to explain how information flows from one memory store to another. There are three permanent structures in the memory system: the sensory register (SR), short-term memory (STM) and long-term memory (LTM)
How does MSM explain SR
Environmental stimuli received through sense enters SR, which has an iconic store for visual info and echoic store for auditory info
Fraction of info from SR is attended to and selected for further processing in STM, otherwise info is lost to decay
How does MSM explain STM
If information in the SR is attended to it is acoustically coded into STM, so similar sounding material can be confused. STM is a temporary store for information received from the SR before it is transferred to LTM.
Info can be kept in STM using maintenance rehearsal known as a rehearsal loop. If there’s sufficient rehearsal or elaborative rehearsal (info organised in certain way) then info transferred to LTM
How does MSM explain LTM
If information is sufficiently rehearsed in STM then it is semantically coded into LTM. This is a permanent store holding vast amounts of information for long periods of time.
When information in LTM is needed it is retrieved by STM and then recalled. Sometimes we cannot access information from LTM because of retrieval failure and so we may need retrieval cues to help us access it.
Evaluation of MSM
PROS:
- NEUROBIOLOGICAL EVIDENCE. Scoville 1957 tried to treat HM’s epilepsy by removing areas of brain (hippocampus). Patient couldn’t code new LTM but STM was unaffected suggesting that they’re two separate things
Shallice and Warrington 1970 investigated patient KF who suffered motorbike accident and had reduced STM capacity of 1-2 digits yet LTM unaffected suggesting their two separate stores
- LAB experiments by Murdock 1962 where pps recalled words at beginning and end better than those in middle (serial position effect) support idea of separate STM and LTM
CONS:
Patient KF had poor STM for verbal tasks but not visual tasks suggesting STM has different types which MSM doesn’t show. Also, LTM was unaffected with KF but LTM is retrieved by STM in MSM so it also should be affected if the STM was damaged
The MSM is over simplified in assuming that there is only one type of STM and one type of LTM. Research studies indicate that there are several types of STM, such as one for verbal information (phonological loop) and another for non-verbal information (visuo-spatial sketchpad). Research also suggests that there are several types of LTM, we have episodic memory for life events, semantic memory for knowledge and facts and procedural memory for motor skills.
Baddeley and Hitch (1974) claimed that the MSM could not explain the ability to multi-task; if there is only one type of STM then multi-tasking would not be possible.
What is the working memory model
Baddeley and Hitch (1974) questioned the idea promoted by the multi-store model (MSM) of memory that people only have one type of short-term memory (STM). They also argued that STM is far more complex than simply being a temporary store for information
They instead saw STM as an active store holding several pieces of information while they are being worked on. They argued that LTM is the passive store that only holds previously learned material to be used by STM when needed.
What is the central executive
The central executive drives the whole working memory system and allocates data to the other components, known as slave systems. It also deals with cognitive tasks such as decision making, reasoning and problem solving.
Individuals have a limited attentional capacity, tasks that are automated make less attentional demands on the central executive and so leave us free to perform other tasks. This explains why we can multitask