memory: coding, capacity and duration

Question 1

research on coding

Answer 1

Baddeley - gave different lists of words to four groups of ppts to remember: Group 1 - acoustically similar (eg cat, cab, can), Group 2 - acoustically disimilar (eg pit, few, cow), Group 3 - semantically similar (eg great, large, big), Group 4 - semantically dissimilar (eg good, huge, hot)
when recalling from STM they tended to do worse with acoustically similar words, but when they were recalling from LTM they tended to do worse in the semantically similar words
This research shows that info in STM is coded acoustically and semantically for LTM.

Question 2

Research on capacity

Answer 2

Jacobs - found out how much info STM can hold by measuring digit span
the researcher read out 4 digits + ppt recalls out loud in correct order then 5 digits and so on.
found the mean span of digits for digits across ppts was 9.3 items.

Question 3

research on STM duration

Answer 3

peterson and peterson - 24 students in 8 trials/tests. each trial ppt was given consonant syllable (eg. YGD) to remember and also a 3 digit number.
the student was to count backwards from this number, to prevent mental rehearsal of the syllable, then stop when asked
on each trial they were asked to stop after varying intervals: 3, 6, 9, 12 etc.
the finding showed at 3s econds recall was at 80% and after 18 seconds it was about 3%
research shows STM’s duration is about 18 seconds

Question 4

research on LTM duration

Answer 4

Bahrick - studied 392 ppts aged between 17 and 74
it included the ppts recalling in various ways from their highschool yearbooks including: 1. photo-recognition test of 50 photos, 2. free recall test everyone from their graduating class
ppts who graduated within 15 yrs 90% accurate in photo recognistion, 48 yrs - 70%
free recall less accurate, 60% after 15 yrs and 30% after 48.
shows LTM can last a lifetime