Evidence for distinction between LTM and STM

Question 1

Evidence that amount of rehearsal controlled the amount of info transferred to LTM

• Asked subjects to rehearse out loud. Rehearsal was tape recorded and analysed in conjuction with written recall data.
• Found that the more they rehearsed, the more was remembered. Primacy effect appears to be attributable to words at beginning of list being rehearsed more, as for a given amount of rehearsal, items from initial serial positions have no better recall than items from the middle of the list. Thus appears that the primacy effect derives from the additional rehearsal accorded to the initial list items.
• Recall probability was the same (.96) for all items present in the final rehearsal set (5 second period). This was the same as that observed for the final list item: suggesting that it is the presence of an iterm in rehearsal at the end of list study which gives rise to the recency effect.

Answer 1

Rundus 1971

Question 2

Made the distinction between primary & secondary memory stores:

• Primary memory: info remaining in consciousness after perception. “the psychological present”
• Secondary memory: info about events that have left consciousness: “the psychological past”
• • influenced Atkinson & Shiffren’s multi-store model, with its distinction between STM & LTM

Answer 2

James 1890

Question 3

Multi-store model proposed.

• attributed primacy effect to storage in LTM, because gerater processing is possible for earlier items (greater rehearsal is possible when relatively few items must be held in mind)
• attributed recency effect to last few items being in short term store from end of list

Answer 3

Atkinson & Shiffrin 1968

Question 4

• 10s filled delay eliminated the recency effect, but did not effect the primacy effect. No effect on recency seen with a 30s unfilled delay, suggesting that counting backwards was the crucial factor, hindering rehearsal and displacing the last few items held in STM
• Primacy effect was unaffected by even a 30s filled delay.

Answer 4

Glanzer Cunitz 196

Question 5

Word familiarity, presentation rate, age of participant etc influence long-term learning, and influence primacy, but nor recency effect.

Answer 5

Glanzer 1972

Question 6

• Asked participants to tell him how many of the words they could from the 10 lists they had already recalled, and plotted word recall according to original list serial position
• Resulting curve was lower overall, reflecting some forgetting
• A negative recency effect was observed: suggests that participants were relying on their short tem store for the last few items in each list during immediate recall- thus at final recall, only items transferred to the long-term store could be recalled, and the last few items in each list were forgotten.

Answer 6

Craik 1970

Question 7

Study 1: Reported patient HM: medial temporal damage

• Impaired long term memory, normal digit span
• Preserved recency effect but much reduced primacy effect.

Study 2: Reported patient KF: damage in left parieto-occipital region

• No problem with long term learning and recall- i.e intact long term memory.
• Digit span greatly impaired, and had recency effect of only 1 item
• Primacy effect was preserved, but no discernable recency effect.

Answer 7

1) Colville & Milner 1957
2) Shallice & Warrington 1970

Question 8

1) Reviewed evidence from 9 fMRI studies
* Reported activity in medial temporal lobe when patients were encoding/ retrieving evidence from long-term memory
2) Inferior frontal and parietal cortex activity associated with asking patients to retain information in short term storage.

Answer 8

1) Schater & Wagner 1999
2) Henson et al 2000