Coding, Capacity & Duration (STM, LTM) Flashcards
Coding in the SR is modality specific. This means…
That each sensory store (e.g. iconic for visual information) codes information differently
How did Baddeley (1966) investigate coding in the STM
- he gave participants 4 lists of words to recall:
-> List A contained similar sounding words, while List B didn’t.
-> List C contained words with similar meanings while List D didn’t.
-> participants performed worse with list A than B, and with no difference between C & D
After his experiment, what did Baddeley theorise
That STM is coded acoustically, meaning it organises information according to how it sounds, so similar sounding words can become muddled.
How did Baddeley (1966) test the coding of LTM
-> he tested the participants recall of the lists from the STM experiment, after a 20 minute delay to ensure that information had passed into the LTM
What were Baddeley’s LTM test results
-> participant recall of list C was worse than list D, and there was no difference between lists A and B.
-> this meant that LTM was coded semantically (organised according to meaning, so similar meaning words could be confused)
Pro and Con of Baddeley’s STM & LTM experiment
- lab experiment and therefore easy to replicate as variables would have been closely controlled (so reliability can be assessed)
- findings have low ecological validity
What’s the capacity of the SR
Unlimited
What was Jacobs (1887)’s test
- digit span test to determine the capacity of STM:
-> he gave participants several sequences of digits, asking them to repeat each sequence right after, in the correct order, with the list getting longer by 1 each time
What did Jacob’s find out
That on average we can hold 9.3 digits and 7.3 letters
That STM capacity gradually improves with age
(But this study was a long time ago, so validity is in question as it may not have been done as scientifically rigorous)
What did Miller (1956) do and conclude
- reviewed psychological research studies, finding that the span of STM is 7 (+/-) 2.
-> otherwise, new incoming info displaces the old stuff
-> that chunking (grouping large amounts of info into smaller groups) helps us remember more (as people remember 5 letters and 5 words the same)
What is the capacity of LTM
Unlimited
How did Peterson & Peterson (1959) use nonsense trigrams to test STM duration
- to prevent participants keeping the information in STM using maintenance rehearsal, they were asked to count backwards from 100 in threes:
-> after 3 seconds, recall was accurate 90% of the time, but after 9 seconds, it dropped to 20% and then after 18 seconds, 2% of the time
What did Peterson & Peterson (1959) conclude about the STM
That information in the STM lasts for 18-30 seconds without rehearsal, before it is lost to decay
Evaluation of Peterson & Peterson’s (1959) STM study
-> research can be said to have a high level of control, as it used standardised procedures & used fixed timings, whilst eliminating noise & other factors which could have influenced memory
-> findings could have been caused by interference, rather that the STM having a short duration (as different trigrams may have gotten confused)
Duration of the SR
250 milliseconds
