Coding, Capacity and Duration Flashcards
What is coding in memory
The format in which information is stored in the various memory stores.
What is capacity in memory?
The amount of information that can be held in a memory store.
What is duration in memory?
The length of time information can be held in a memory store.
What are the features of STM?
- Coding: Mainly acoustic
- Capacity: 5–9 items (Miller’s magic number 7 ± 2)
- Duration: 18–30 seconds
What did Peterson & Peterson (1959) find about STM duration?
Without rehearsal, STM lasts about 18–30 seconds. Performance declined rapidly over increasing retention intervals.
How did Peterson & Peterson test STM duration?
Participants had to remember trigrams (e.g., YCG) while counting backwards to prevent rehearsal. They recalled fewer as retention interval increased.
What are the features of LTM?
- Coding: Mainly semantic
- Capacity: Unlimited
- Duration: Up to a lifetime
What did Bahrick et al. (1975) find about LTM duration?
- Photo recognition: 90% accurate within 15 years, 70% after 48 years
- Free recall: 60% accurate within 15 years, 30% after 48 years
What did Jacobs (1887) find about digit span?
Mean span for digits was 9.3; for letters, it was 7.3 items.
What did Baddeley (1966) discover about coding?
- STM is coded acoustically (confused similar-sounding words)
- LTM is coded semantically (confused similar-meaning words)
What did Miller (1956) suggest about STM capacity?
STM capacity is about 7 ± 2 items. We chunk information to remember more.
What is chunking in memory?
Grouping digits or letters into meaningful units to increase STM capacity.
What is a limitation of Baddeley’s study?
Used artificial stimuli (word lists), so lacks ecological validity and may not apply to everyday memory.
What is a limitation of Jacobs’ digit span study?
Lacked control due to being an early study – participants may have been distracted, affecting validity. But findings confirmed by later studies.
What is a limitation of Miller’s STM capacity theory?
Cowan (2001) suggested STM capacity is only about 4 chunks, so Miller may have overestimated it.
What is a limitation of the Peterson & Peterson study?
Used meaningless trigrams – lacks ecological validity as real-life memory usually involves meaningful information.
What is a possible alternative explanation for forgetting in their study?
Displacement – new information (e.g. counting backwards) may have pushed old information out of STM, not just decay.
What is a strength of Bahrick’s study?
High external validity – tested real-life, meaningful memories like names and faces.
What is a limitation of Bahrick’s study?
Confounding variables – participants may have looked at yearbooks or rehearsed names over the years.
What trend is shown in the graph for STM retention?
% correct responses decreased as retention interval increased, supporting the idea that STM has a short duration.
How could counting backwards cause displacement in STM?
Counting introduces new information into STM, potentially replacing the trigrams due to limited STM capacity.
