coding, capacity and duration ao1 Flashcards
Coding definition
The way in which information is changed to be in a format which is stored in memory eg semantic acoustic
Formats in which memory is stored in
Visual
Acoustic
Semantic (experience)
Who did research coding and when
Baddely
1966
Describe baddelys research into coding
4 groups
Group 1: acoustically similar - cat cab cab
Group 2: acoustically disimilar - pit few cow
Group 3: semantically sim - great large big
Group 4 : semantically disimilar - good huge hot
Participants were shown word lists and then asked to recall in correct order
They were asked to recall immediately (STM) and after 20 mins (LTM)
Findings from baddelys research
When asked to immediately recall (STM) ppts did worse acoustically similar - they had acoustic confusion
When asked to recall after 20 mins (LTM) ppts did worse w semantically sim words - had semantic confusion
Thus STM codes acoustically
LTM codes semantically
Capacity definition
The amount of info that can be held in a mem store
Who and when did research on capacity
Digit span - Jacobs 1887
Span of memory and chunking - George miller 1956
Describe Jacob’s stm capacity
He read out 3 digits and ppts recall these out loud if in the correct order another digit added until ppt cannot recall order correctly
This indicates individual digit span
Findings from Jacob’s study on stm capacity
Mean span for digits - 9.3
Mean span for letters - 7.3
Miller findings
Capacity of STM is 7+-2 items
Chunking - grouping sets of digits or letters into chunks or units
Who and when did Research on duration
Duration of STM - Peterson and Peterson 1959
Duration of LTM - Bahrick et al 1975
Describe Peterson and Peterson study on duration of STM
tested 24 students
In each trial ppt given consonant syllable ( trigram eg YDH) to remember . They were also given 3 digit number. Ppt asked to count backward from number until told to stop. This is to prevent rehersal of trigrams.
On each trial retention interval increased eg 3 sec 9 sec 12 sec 18 sec
Findings of Peterson and Peterson
After 3 sec = average recall was 80%
After 18 sec = average recall was 3%
So findings suggested that STM duration may be ab 18 - 30 sec unless info repeated over and over ( eg verbal reh)
Describe bahricks study on duration of LTM
392 American ppts aged bet 17-74 and tested recall using year books in one of 2 ways - photo recognition and free recall
Photo recognition- had to say names from pic
Free recall - no pics jsur name ppl
Findings from bahrick study - duration of Ltm
Ppts tested within 15 years of graduating had 90% accuracy in photo rec
After 48 years this fell to 70% for photo rec
Free recall was less accurate
After 15 years it was 60 % accuracy
after 48 years dropped to 30%
Shows that duration of LTM could be ulimited / last a lifetime
