TEMPORARY MEMORY: SHORT-TERM AND WORKINGMEMORYLearning & MemoryArlo Clark-Foos, Ph.D.

INFORMATION PROCESSING MODELAtkinson & Shiffrin (1968)

SHORT-TERM MEMORY

Ability to store information in current consciousness without active rehearsal

Tasksn-backSerial Addition

PASAT

Working Memory?

DISTINCTIONS

Capacity

Forgetting

Components and Functions

Animal WM?

Neural representations of WM

HOW SHORT IS SHORT-TERM MEMORY?Sensory Memory

Iconic Partial Report Procedure (Sperling, 1960)< 1 sec

Echoic (Darwin et al., 1972)< 2-3 sec

SHORT-TERM MEMORY CAPACITY

Miller’s Magic Number 7 ± 2 (1956)Persecuted by a numberDigit Span

Other Span Tests (Reading, Sentence, O-Span, etc.)

Free RecallSerial Position Effects

PrimacyRecencyRole of long-term vs. short-term memory?

SERIAL POSITION EFFECTS

IMPROVING STM CAPACITY

Chunking

Ericcson, Chase, & Faloon (1980)

DURATION OF SHORT-TERM MEMORY

Brown-Peterson TaskBrown (1958) & Peterson and Peterson (1959)Forgetting CurveDecay?

FORGETTING CURVES

Different ModalitiesSimilar patterns

DURATION OF SHORT-TERM MEMORY

Proactive InterferenceKeppel & Underwood (1968)

ATKINSON & SHIFFRIN (1968): STS

SHORT-TERM VS. LONG-TERM

DistinctionsCapacityAnatomical (more later)Representational Coding

SimilarityInteractions (e.g., proactive interference)

REPRESENTATIONAL CODING

Kintsch & Buschke (1969)Serial Position & ErrorsSynonyms vs. HomophonesSemantic vs. Perceptual Similarity

ANATOMICAL DISTINCTIONS

Amnesics (Baddeley & Warrington, 1970)HippocampusH.M.Korsakoff’setc.

Temporoparietal Damage (Shallice & Warrington, 1970)No STM (recency of one), intact LTM

SHORT-TERM STORE VS. WORKING MEMORY

Baddeley (2000)

Baddeley & Hitch (1974)

Atkinson & Shiffrin (1968)

WORKING MEMORY

Baddeley & Hitch (1974)Central ExecutiveVisuospatial SketchpadPhonological Loop

Subvocal Rehearsal

Rehearsal RatesLanduer (1962)Ellis & Hennelly (1980)

Ode on WM (Keenan)

Quinn & McConnell (1996)

WORKING MEMORY

Properties of the Phonological LoopSalame & Baddeley (1987; 1989)

WORKING MEMORY

Properties of the Visuospatial SketchpadBaddeley et al. (1975)

DO ANIMALS HAVE WORKING MEMORY?Serial Probe Recognition Task (Wright et al. 1985)

NEUROLOGICAL BASIS OF WMPrefrontal Cortex (PFC)

SHORT-TERM MEMORY AND THE PFCJacobsen et al. (1937): Bilateral PFC Lesions

Delayed Response Task

FRONTAL PATIENTS

Perseverate (WCST; Roberts et al., 1996)

Proactive Interference (Shimamura et al., 1995)

Meta-Memory (underconfident JOL)

Source Memory (Dobbins et al. 2002)

Shimamura et al. (1995)

R.J. (Baddeley, 1986)ConfabulationDisexecutive Syndrome

Inability to contemplate current and recalled events or to interpret the validity and implications of those experiences to draw reasonable conclusions

PFC CONNECTIONS

InputDLPFC

SomatosensoryVisualspatial“Where”

LPFCAuditory, Olfactory, Taste, and Visual Pattern Information“What”

IT’S A BIG PFC AFTER ALL

Not just one big lump of grey matter…

Lateralized (Smith et al., 1996)n-back task (Spatial vs. Verbal)

SMITH ET AL.’S (1996) N-BACK TASKS

Baddeley & Hitch (1974)

Smith, Jonides, & Koeppe (1996)

Right Hemisphere

Left Hemisphere(Broca’s area?)

SHORT-TERM MEMORY AND THE PFCJacobsen et al. (1937): Bilateral PFC Lesions

Delayed Response Task

Lesion to ____ affected ______:

DLPFC Spatial WMLPFC Object MemoryOPFC Sensory Discriminations

~ in other species too (Kolb & Robbins, 2003)

TASK SWITCHING AND PRODUCTION RULES

Intra vs. Extradimensional Shifts (Dias et al. 1996)

Reward Contingencies

New Production Rule

DELAY CELLS

Fuster (1995)Goldman-Rakic (1995)

Occular motor delayed response taskDLPFC lesion

mnemonic scotoma

CATEGORICAL PERCEPTION (FREEDMAN ET AL., 2001)

Firing rate of cells in PFC

WORKING MEMORY LOAD

Cohen et al. (1997): n-back (0,1,2,3)

WORKING MEMORY LOAD

Cohen et al. (1997): n-back (0,1,2,3)

PFC: Active throughout delayVisual Area: Active late in delayBroca’s Area: Greatest activation for high load at high delay

PFC-HIPPOCAMPUS INTERACTIONS

PFC-HIPPOCAMPUS INTERACTIONS