coding, capacity and duration Flashcards
who researched coding?
Baddeley (1966)
outline Baddeley’s procedure
acoustically similar words ( cat, can, cab) or dissimilar (pit, few cow)
semantically similar words (big, large, huge) or dissimilar (good, huge, hot)
what were Baddeley’s findings
immediate recall was worse with acoustically similar words - STM is acoustic
recall after 20 mins was worse with semantically similar words - LTM is semantic
one strength of Baddeley’s research (coding)
-identified 2 memory stores
-led to the development of the multistore model
one limitation of Baddeley’s research (coding)
-artificial stimuli
-words had no personal meaning to the PPs so has limited application to everyday
who researched capacity? - digit span
Jacobs (1887)
outline Jacobs research
researcher reads 4 words and increases until the PP cant recall the order correctly final number= digit span
what were Jacobs findings?
mean span for numbers = 9.3
mean span for letters is = 7.3
one strength of Jacobs research
-replicated
- findings consistent with later studies
one limitation of Jacobs research
lacked adequate control of confounding variables ( pps getting distracted)
who researched capacity? (magic number)
Miller (1956)
outline Miller’s procedure
observed everyday practice and found things come in 7s
what were Miller’s findings?
span of STM is 7 items (+-2) but can be increased by chunking
one limitation of Miller’s study
-overestimates STM capacity
- Cowen (2001) - capacity is only 4 chunks
who researched the duration of STM
Peterson and Peterson (1959)
outline the Peterson’s procedure
24 students given a consonant syllable to recall and a 3 digit number to count back from to stop rehearsal - retention interval was varied
what were the Peterson’s findings
3 secs = 80%
18 secs = 3%
duration of STM is 18 secs with no rehearsal
one limitation of The Peterson’s study (duration)
-meaningless stimuli
recall of consonant syllables doesn’t reflect everyday tasks
-lacks external validity
who researched the duration of LTM ?
Bahrick et al (1975)
outline Bahrick’s procedure
- 392 americans aged 17-74
- 1) recognition test from 50 photos from yearbook
- 2) free recall test list names of their graduation clas
what were Bahrick’s findings?
- recognition test
15 years = 90%
48 years = 70% - free recall test
15 years = 60%
48 years = 30%
one strength of Bahrick’s study (duration)
-high external validity
- used meaningful memories
