coding, capacity and duration of memory Flashcards
what is the research on coding
baddeley-gave different lists of words to 4 groups of pps to remember
group 1- acoustically similar
group2-acoustically dissimilar
group 3-semantically similar
group 4-semantically dissimilar
pps shown original words and asked to recall them in correct order
when done immediately recalling from short term memory tended to do worse with acoustically similar words
when recalled after time of 20mins long term memory they did worse with semantically similar words
info coded acoustically stm and semantically in ltm
what is the research on digit span (capacity)
jacobs- measured digit span
researcher reads out 4 digits and pps recalls out loud in correct order
if correct research reads out five digits and so on until pps cant recall order correctly
indicates individuals digit span
mean span for digits- 9.3 items
mean span for letters was 7.3
what is research on span of memory and chunking (capacity)
miller-observations of everyday practice
things come in sevens
iller thought span is 7 items plus or minus 2
people can recall five words as easily as five letters
do this through chunking- grouping sets of digits or letters into units or chunks
what is research on duration of stm (duration)
peterson and peterson-tested 24 students in 8 trials
on each trial student given consonant syllable and three digit number
student counted backwards from number until told to stop
counting backwards prevented mental rehearsal of consonant syllable
on each trial-told to stop after varying periods of time- 3 6 9 12 15 or 18secs
after 3secs- avg recall 80% after 18secs avg recall 3%
suggested stm duration may be 18secs unless repeat info over and over
what is duration of ltm (duration)
bahrick-392 american pps aged 17-74
high school yearbooks obtained from pps or directly from some schools
recal tested in various ways- photo recognition testing 50photos some from pps high school yearbooks and free recall test where pps recalled all names of graduating class
tested within 15years graduation were 90% accurate in phot recognition
tested after 48yrs recall declined 70% for photo recognition
after 15yrs 60% free recall and 30% after 48yrs
ltm may last lifetime for some material
what is separate memory stores (braddleys eval)
identified clear difference between two memory stores
some exceptions to baddeleys findings
idea stm uses acoustic coding and ltm semantic has stood test of time
important step in understanding memory system led to multi store model
what is artificial stimuli (baddeley eval)
used artificial stimuli rather than meaningful material
word list had no personal meaning to pps
findings may not tell us much about coding in different kinds of memory tasks in everyday life
when processing more meaningful info people may use semantic coding even for stm tasks
suggests findings from study have limited application
what is a valid study (jacobs eval)
replicated
old study and early research lacked adequate controls
some pps digit spans might have been underestimated because they were distracted during testing
jacobs findings have been confirmed by other better controlled studies since
jacobs study valid test of digit span in stm
what is not so many chunks (miller eval)
may have overestimated stm capacity
cowan-reviweed other research and concluded that cpaacity of stm is only about 4 plus or minus 1 chunk
suggests lower end millers estimate is more appropriate than seven items
what is meaningless stimuli in stm study (peterson and peterson eval)
stimulus material artificial
study not irrelevant because we sometimes try to remember fairly meaningless material
recalling consonant syllables does not reflect most everyday memory activities where what we are trying to remember is meaningful
study lacked external validity
what is high external validity (bahrick eval)
high external validity
researchers investigated meaningful memories
studies ltm conducted with meaningless pictures to be remembered recall rates lower- shepard
bahricks findings reflect more real estimate of duration of ltm
