short term and working memory Flashcards
(18 cards)
What is STM?
A limited-capacity store that represents the present moment and links sensory input with LTM.
What is the capacity and duration of STM?
Capacity: 7 ± 2 items
Duration: 15–30 seconds
What is maintenance rehearsal?
Repeating information using an “inner voice” to keep it active and transfer it to LTM.
What evidence supports rehearsal’s role in LTM transfer?
Primacy effect—early list items get rehearsed more and enter LTM.
How is STM capacity measured?
Digit-span task – recall increasing sequences of digits → average = 7 ± 2 items.
How is STM duration measured?
Brown-Peterson task – recall 3 consonants after counting backward.
What are the results of the Brown-Peterson task?
Recall:
50% after 3 seconds
20% after 9 seconds
Near 0% after 12–18 seconds
What is the serial position effect?
Better recall for early (primacy) and late (recency) list items.
What causes the primacy effect?
More rehearsal → transfer to LTM.
What causes the recency effect?
Items still active in STM.
What happens when rehearsal or STM is disrupted?
No recency effect with a retention interval
No primacy effect if rehearsal is blocked
What do these effects suggest?
STM and LTM are separate systems, and rehearsal mediates transfer.
What did Craik & Tulving (1975) test?
Depth of processing affects memory encoding.
What were the three processing levels?
Shallow (visual)
Intermediate (phonetic)
Deep (semantic)
What were the results?
Semantic processing led to best recall → challenges the idea that rehearsal alone enables LTM transfer.
What are the four components of working memory?
Phonological Loop – Verbal/auditory info (e.g., digit span)
Visuo-Spatial Sketchpad – Visual/spatial info (e.g., mental rotation)
Central Executive – Attentional control and planning
Episodic Buffer – Multimodal integration for conscious episodes
What is the neural basis for each component?
PL: Left fronto-temporal
VSS: Right occipital-parietal
CE: Prefrontal cortex
EB: Parietal cortex
How is WM different from STM?
Working memory is active, multi-component, and involved in reasoning—not just passive storage.
