Memory Flashcards
Definition of coding
The format in which information is stored in the various memory stores
Definition of capacity
The amount of information that can be held in a memory store
Definition of duration
The length of time information can be held in memory
Coding of short term memory?
Mainly acoustic (sounds)
Capacity of short term memory?
Between 5 and 9 items (average)
Duration of short term memory?
Between 18 and 30 seconds
Coding of long term memory?
Mainly semantic (meaning)
Capacity of long term memory?
Unlimited
Duration of long term memory?
Up to a lifetime
When did Alan Baddeley conduct his research?
1966
What was Alan Baddeley’s research looking at?
Coding
Alan Baddeley Research Procedure:
Gave different lists of words to four groups of participants to remember:
- Group 1 (acoustically similar): words sounded similar (e.g. cat, cab, can)
- Group 2 (acoustically dissimilar): words sounded different (e.g. pit, few, cow)
- Group 3 (semantically similar): words with similar meanings (e.g. great, large, big)
- Group 4 (semantically dissimilar): words that all had different meanings (e.g. good, huge, hot)
Participants shown original words and asked to recall them in the correct order
Alan Baddeley Research Findings/conclusion?
When the participants did the recall task immediately after hearing the words (STM recall), they did worse with acoustically similar words
When the participants did the recall task after 20 mins (LTM recall), they did worse with semantically similar words
Suggests info is coded semantically in LTM
What piece of research looks at coding?
Alan Baddeley (recall of different groups of words)
What is a limitation of Baddeley’s study?
- Artificial stimuli rather than meaningful material
- Word list had no meaning to participants
- Findings may have limited application (more meaningful info may use semantic coding even for STM tasks)
What pieces of research looks at capacity?
Joseph Jacobs (1887) - see how many digits one can remember
George Millie (1956) - things come in 7s
Joseph Jacobs Research Procedure:
- Researcher gives (e.g.) 4 digits and participant asked to recall in correct order aloud
- If correct, researcher reads out 5 digits and so on until participant cannot recall order correctly
- Determines their digit span
When did Joseph Jacobs do his research?
1887
What was Joseph Jacobs research looking at?
Capacity/ digit span
Jacob Joseph Research Findings:
Mean span for digits across all participants was 9.3 items
Mean span for letters was 7.3
What is a limitation of Jacob Josephs study?
Lacks validity
- conducted a long time ago (early research often lacked adequate control)
- May be confounding variable that were not controlled
(although results have been confirmed in other research supporting validity)
What did George Miller research into?
Span of memory (capacity) of STM and chunking
What was George Miller’s observations and suggestions?
- Observations of everyday practice
- That things came in 7s (musical notes, days of week, 7 deadly sins…)
- Suggests that the capacity of STM is 7 (+ or - 2)
- People can recall 5 words as well as they can recall 5 letters due to chunking (grouping sets of digits or letters into units or chunks)
What is chunking (George Miller)?
Group sets of digits or letters into units or chunks
What is a limitation of George Miller’s research?
Research Support:
- Overestimated the capacity of STM
- Cowan (2001) reviewed other research and concluded that the capacity of STM was only about 4 chunks
- Suggests that the lower end of Miller’s lower end of Miller’s estimate (5 items) is more appropriate than 7 items
What was Margaret and Lloyd Peterson research looking at?
Duration of STM
What piece of research looks at duration of STM?
Margaret and Lloyd Peterson (remembering a consonant syllable/trigram - e.g. YCG)
What year did Margaret and Lloyd Peterson conduct research?
1959
Margaret and Lloyd Peterson Research Procedure:
- 24 undergraduate students
- 8 trials
- Each trial, student given consonant syllable/trigram (e.g. YCG) to remember and also given three digit number
- Asked to count backwards from the 3-digit number (prevents mental rehearsal of trigram)
- Each trial, told to stop after different amount of time (3,6,9,12,15,18seconds - called retention interval)
Margaret and Lloyd Peterson Research Findings:
- As the retention interval increases, % of correct responses decrease
- Suggests STM has short duration unless repeated over and over again (verbal rehearsal)
What is a limitation of Margaret and Lloyd Peterson’s study?
- Stimulus material was artificial
- Memorising consonant syllables does not reflect most real-life memory activities where what we are trying to remember is meaningful
- Low external validity
- Although, do have to remember meaningless things e.g. phone numbers
What research looks at duration of LTM?
Harry Bahrick et al.
What does Harry Bahrick et al. research look at?
Duration of LTM
What year did Harry Bahrick et al. do his research?
1975
What participants took part in Harry Bahrick et al. research?
- 392 participants from Ohio
- Aged between 17 and 74
Bahrick et al research procedure:
- High school yearbooks obtained from participants or from some schools
- Photo-recognition recall test of 50 photos
- Free recall test where participants recalled all names of their graduating class
Bahrick et al. research findings:
- After 15 years of graduation 90% accurate for photo recognition
- After 48 years of graduation 70% accurate for photo recognition
- After 15 years of graduation 60% accurate for free recall
- After 48 years of graduation 30% accurate for free recall
- LTM lasts very long time
Strength of Bahrick et al. study?
- High external validity
- Real life meaningful memories
Limitation of Bahrick et al. study?
- Due to being such real-life research, confounding variables not controlled
- E.g. Bahrick’s participants may have looked at their yearbook photos and rehearsed their memory over the years
What is the sensory register?
Memory stores for each of our 5 senses
Who made multi-store model? When?
Richard Atkinson and Richard Shiffrin (1968, 1971)
What are the three stores in the multi-store model?
Sensory register, STM and LTM
What are the two main stores in the sensory register? How are they coded?
Iconic memory (visual information is coded visually)
Echoic memory (sound/auditory information is coded acoustically)
What is the duration of the sensory register?
Less than half a second
What is the capacity of sensory register?
Very high
How does information get further than the sensory register?
Paying attention to it
Does much information make is past the sensory register?
No, very little
How is information in the STM coded? How long does it last?
- Acoustically
- Lasts about 30 seconds unless rehearsed
What is maintenance rehearsal?
When we repeat and rehearse material to ourselves over and over again
How does info stay in the STM and go into LTM?
By rehearsing it, it stays in the STM
By rehearsing it long enough, it passes into LTM