Research into Features of Memory

theory that investigates the capacity of STM?


Miller's 1956 Magic Number (7±2)

what is Miller's theory based on?


Jacob's (1887) Digit Span Research (empirical study); used systematic review and meta-analysis of existing research to formulate his theory

aim of Miller's theory?


investigate the capacity of STM and the use of chunking as a method to increase capacity

findings/conclusions of Miller's theory?


conclusions-->

• capacity of STM is 7±2 items (between 5 and 9)

• People can increase memory capacity by organising items, bits of data/info together into meaningful, memorable units (concept= 'chunking')

research that evidences the capacity of STM?


Jacob's (1887) Digit Span

procedure of Jacob's Digit Span?

• used digit span test with every letter in alphabet, excluding "w" and all numbers, excluding "7" (two or more syllables/control EVs-pronunciation length)

• sequence of numbers and letters increased in length until ppts. could no longer recall them correctly

findings of Jacob's Digit Span?

average span for letters 7.3

average span for numbers 9.3

findings of Jacob's Digit Span?

capacity for STM is limited, also ppl find it easier to recall numbers rather than letters

study that evidences duration of STM?


Peterson & Peterson (1959)

aim of Peterson and Peterson study?

to investigate how long information is retained in STM without rehearsal

procedure of Peterson and Peterson study?


• sample of 24 Psychology students were each given a consonant syllable (e.g.

GWN) and a 3-digit number (e.g. 138) .

• then asked to count backwards from the 3-digit number (distraction task) until they were told to stop

• after they had to recall the syllable/trigram.

• Participants were then asked to recall the syllables at increasing, predetermined time intervals (3,6,9,12,15 and 18 seconds) .

findings of Peterson and Peterson study?

results showed after 3 seconds, average recall was 80%

after 18 seconds, average recall was 3%

(longer delay, less info recalled)