Coding Capacity and Duration of Memory Flashcards
Short-term memory.
The limited-capacity memory store.
Capacity - Between 5 and 9 items.
Coding - Acoustic (sounds).
Duration - 18 seconds.
Long-term memory.
The permanent memory store.
Capacity - Unlimited.
Coding - Semantic.
Duration - Lifetime.
Define the term coding.
The format in which information is stored in the various memory stores.
What were the procedures of Baddeley’s research on coding?
Gave different lists of words to four groups of participants. Group 1 acoustically similar. Group 2 acoustically dissimilar. Group 3 semantically similar. Group 4 semantically dissimilar.
What were the findings of Baddeley’s research on coding?
When recalling from short-term memory, they tended to do worse with acoustically similar words.
When recalling from long-term, they did worse with the semantically similar words.
Information is coded acoustically in STM and semantically in LTM.
What is a strength of research on coding?
Identified a clear difference between two memory stores
What is a limitation of research on coding?
Used artificial stimuli rather than meaningful material.
Word list had no personal meaning to participants so Baddeley’s findings may not tell us about coding in everyday life.
When processing more meaningful information, people may use semantic coding even for STM tasks.
Define the term capacity.
The amount of information is stored in the various memory stores.
Explain Jacobs study linking to the capacity of short term memory.
Jacobs in 1887 – digit span.
The researcher reads out four digits and the participant recalls these out loud in the correct order if correct researcher adds one more digit until the participant can’t recall the order correctly showing participants digit span.
Jacobs found that the mean digit span across all participants was 9.3 items.
The mean span for letters was 7.3.
Explain Miller’s study linking to the capacity of short term memory.
Miller (1956) - span of memory and chunking
Made observations of everyday practice.
And concluded that the capacity of STM is 7 plus or minus 2 ‘bits’ of information. He also noted that in order to increase this capacity, people ‘chunk’ information together.
What are the strengths of research on capacity?
Jacobs’ study has been replicated.
Old research that lacked adequate controls.
Despite this, Jacobs’ findings have been confirmed by other, better controlled studies since.
This suggests Jacobs’ study is valid.
What are the limitations of research on capacity?
Overestimated STM capacity.
Cowan (2001) reviewed other research and concluded that the capacity of STM is only 4 +/- 1 chunks.
Lower end of Miller’s estimate 5 is more appropriate.
Define the term duration.
The length of time information can be held in memory.
What is the study linking to the duration of short term memory?
Margaret and Peterson (1959)
Tested 24 students in 8 trials.
Given consonant syllable and 3-digit number to remember.
Students counted backwards to prevent mental rehearsal.
Each trial they were told to stop varying times 3,6,9, etc seconds.
Findings: 3 secs recall was 80%, 18 secs recall was 3%
STM duration 18 seconds unless we repeat.
What is the study linking to the duration of long term memory?
Bahrick et al. (1975).
Studied 392 American participants aged between 17 and 74 were required to identify schoolmates from their high school yearbook, name them in a free recall test, or match photos to names.
Participants who left school within 15 years were very accurate with photo recognition (90%),
After 40 years was 70% accurate. Older participants were less good at free recall, but nearly as good as younger participants in the matching task. The conclusion was that the duration of LTM is potentially lifelong.
