PSYCH; Short Term Memory

EXAM TIP; if asked to describe study (only include procedure) if asked what a study shows (only include findings/conc)

coding in STM

information is coded acoustically

investigated by Baddeley (1966)

procedure of Baddeley (1966)

gave different word lists to 4 groups of p’s to remember;

grp1 - acoustically similiar words (sounded similar)

grp2- acoustically dissimilar words (sounded different)

grp3 - semantically similiar words (similiar meanings)

grp4 - semantically dissimilar words (different meanings)

p’s were shown the words and asked to recall them in the correct order

findings of Baddely (1966)

• when they recalled immediately (testing STM);

worse recall with acousitcally similiar words

• when recalled 20 minutes later (testing LTM);

worse recall with semantically similiar words

conc; suggests information is coded acoustically in STM and semantically in LTM

capacity in STM

limited - between 5 and 9 items (7±2)

Miller 1956 suggested capacity can be improved via chucking method

Miller’s study on capacity in STM

made observations of everyday practice;

noted that things come in sevens e.g. 7 days of the week

suggested that the capacity of STM is 7±2 items

and noted that capacity can improved by chunking (grouping sets of digits/letters)

duration of STM

short - about 3-18 seconds;

investigated by Peterson (1959)

but info can be kept in STM longer via maintenance rehearsal

if released long enough can be passed into LTM

whats meant by maintenance rehearsal

when we repeat (rehearse) materials of info to ourselves over and over

to be kept longer in our STM or if rehearsed long enough can be passed onto LTM

procedure of Peterson’s study on duration of STM

tested 24 students in 8 trials;

on each trial the student was given a consonant syllable (e.g. YCG) to remember.

also given a 3 digit number

the student counted backwards from this number until told to stop (to prevent any mental rehearsal of the consonant syllable which could increase the duration of STM for the syllable)

on each trial were told to stop after different time intervals (retention interval)

findings/conc of Peterson’s study on duration of STM

after 3 seconds, average recall was approx 80%

after 18 seconds it was about 3%

conc; suggests STM duration is about 3-18 seconds without any rehearsal