research on coding, capacity, duration Flashcards
what is coding
process of converting information between different forms of
—> format in which information is stored in various memory stores
what was the research on coding
Alan Baddley gave different lists of words to 4 groups to remember
Group 1 acoustically similar (sounded similar
Group 2 acoustically dissimilar
Group 3 semantically similar (similar meanings)
Group 4 semantically dissimilar
—> ppts showing original words and asked to recall them in correct order
—> when did task immediately (STM) they did worse with acoustically similar words and when recorded list after 20 mins (LTM) they did worse with semantically similar words
—> suggests info is coded acoustically in LTM and semantically in STM
eval of research in coding
- it identified a clear different between 2 memories stores and their ideas of STM and LTM have stood a long time —> was imoortnat steps in our understanding of multi store model and memory system
- artificial stimuli (word lists) had no personal meaning to ppts= findings don’t tell us much on coding in different memory tasks = limited application
what is capacity
how much info that can be held in memory store
what was the first research on capacity
DIGIT SPAN
- Joseph Jacobs
- he read out 4 digits and ppt recalls these out loud, if correct researcher reads out 5 digits and so on until ppt cant recall order correctly = indicates individuals digit span
—> Jacobs found mean span for digits across ppts= 9.3 items and a mean span for letter= 7.3
eval on Jospeh Jacob’s research
- study was replicated and has high validity BUT lacks control e.g. same ppts digit span could be underestimated cause they may have been distracted etc (confounding variables )
BUT
other studies like Bopp had similar findings= more validity
research on capacity number 2
SPAN OF MEMORY AND CHUNKING
- Miller
- made observations of everyday practice e.g. noted things come in sevens (7 days of week etc) —> Miller though capacity of STM is about 7 +/- 2
But also noted ppl recall 5 words easier than 5 letters—> we do this by chunking
what is chunking
- grouping sets of digits of letters into chunks
eval of Millers research
- he may have overestimated STM capacity —> Cowan suggested STM= around 4 +/- 1 chunks
what is duration?
length of time info is held in the memory
what was the research into the duration of STM?
- Margaret and Peterson tested 24 students in 8 trials each
—> each trial student = given consonant syllable to remember and a 3 digit number
—> student counted back from this number until told to stop (to prevent mental rehearsal of the consonant syllable)
—> each trial ppts asked to stop after ever varying periods of time
—> after 3 secs avg recall was around 80% after 18 secs about 3%
—> Oeterson and Peterson findings= suggested STM duration may be about 18 secs unless we repeated the info over and over (verbal rehearsal)
eval of the research into duration of STM
- stimuli= artificial
BUT
study not completely irrelevant as we do try to remember fairly meaningless things e.g. phone numbers
—> arguably the task was still meaningless and doesn’t reflect everyday activities = lack external validity
what was the research into duration of STM?
Bahrick et al studied 392 American ppts (aged 17-74)
—> high school yearbooks were obtained from ppts and recall was tested in various ways
—> photo recognition test, free recall test (recall names of ppl in class etc)
—> ppts tested within 15 years of graduation = 90% accurate in photo recognition
—> after 48 years recall dropped to 70% for photo recognition
—> free recall is less accurate (60% after 15 years and 30% after 48 years)
—> shows LTM may last up to a lifetime for some material
research into STM duration eval
- high external validity
—> researchers investigated meaningful memories —> studies in LTM conducted with meaningless pics to be remembered = recall rates lower (Shepard) —> suggests Bahricks findings = more real estimate of duration of LTM
