SHORT TERM (WORKING) MEMORY

• The phenomenology of STM

• Information-Processing models

– Broadbent’s “p-system” (1958)

– Waugh & Norman’s primary memory (1965) (borrowing James’ term)

– Atkinson & Shiffrin’s multistore model (1968)

MEMORY STRUCTURES AND PROCESSES IN

THE “MODAL MODEL”(Atkinson & Shiffrin, 1968)

SENSORY REGISTERSsensoryinputs

SHORT-TERM STORE (STS)temporary, working memory

LONG-TERM STORE (LTS)

permanent memory store

visual auditory

control processes: - rehearsal - coding - decisions - retrieval strategies

tactile

• Characteristics of the short-term store: the classic period– Brief duration

• (Peterson & Peterson 1959)– Limited capacity

• (Miller, 1956)– Dominance of speech-like codes

• (Conrad, 1964; Baddeley 1966)– Serial “retrieval” process

• (Sternberg 1966)– STM Rehearsal consolidates LTM

• (Rundus & Atkinson 1971)– Forgetting through decay

• (Peterson & Peterson 1959)– Or displacement

• (Waugh & Norman 1965)

SUPPORT AND PROBLEMS FOR THE CLASSIC VIEW

• Dissociations in amnesia– HM, others show STM LTM failure– But PV, others learn despite poor STM

• Recency effects in free recall– Distraction after last word eliminates it

(Glanzer & Cunitz, 1965)– But distraction after every word doesn’t

(Bjork & Whitten, 1974)

• Primacy effects in free recall– Strong correlation between rehearsal

and recall (Fischler & Rundus, 1970)– But this can be decoupled by

‘maintenance” rehearsal (Craik & Watkins, 1975)

• STM capacity and speech– Impact of speech on capacity, errors

(e.g., Baddeley, 1966)– But visual, semantic codes may also

play a role in “STM” tasks (e.g., Baddeley & Hitch, 1974)

Brain activity and theSTM-LTM distinction

• Talmi, et al. (2005)– 12-word lists shown visually– Test for recognition early vs. late in seq– BOLD response (fMRI) contrasted

Earlyvs Late:

EarlyvsControl:

So:LTM retrievalactivates MTL;STM retrievaldoes not