STM and LTM Flashcards
What is Capacity?
how much data can be held in a memory store
What is the capacity of STM?
Jacobs (1887)
Digits - 9.3 items
Letters - 7.3 items
What is the capacity of LTM?
Miller (1956)
7 +/- 2
What is duration of STM?
Peterson + Peterson (1959)
90% correct over 3 seconds
2% correct after 18 seconds
SO less than 18 secs
What is duration of LTM?
Bahrick et al (1975)
60% accuracy after 15 years
30% accuracy after 48 years
Evaluation Point 1 for Capacity
the size of chunks matter
Simon found that people had a shorter memory span for larger chunks
Evaluation Point 2 for Capacity
Individual Differences
capacity for STM is not the same for everyone
Jacobs found that recall increased with age.
8 year olds could remember an average of 6.6 digits whereas 19 year olds could remember of an average of 8.6 digits.
This could be because of changes in brain capacity OR because of development in strategies like chunking.
Evaluation Point 1 for Duration
Criticism of Peterson + Peterson’s study os that it did not measure what it was set out to measure.
This is because the ppts were counting the numbers in their STM
and this may displace the syllables to be remembered. So, Reitman used auditory tones instead and found duration of STM was longer.
What is coding?
the way information is changed so that it can be stored in memory
acoustic and semantic coding
Baddeley (1966)
Examples of acoustic coding?
can, cab, cat
Examples of semantic coding?
huge, big, massive
Evaluation 1 of coding
Since the study was standardised and can easily be replicated, it presents high reliability.
Evaluation 2 of coding
Given that it is a laboratory study, has low ecological validity; it is unlikely that the procedure is used in everyday life.
