1. THE “WORKING MEMORY” APPROACH Baddeley & Hitch (1974) –Use articulatory suppression to interfere with some tasks, not others B doesn’t precede AB A –Develop “Working Memory” model: Desk-top metaphor for STM Process & storage tradeoff –(e.g., Posner & Rossman 1965) Multicomponent structure

2. COMPONENTS OF WORKING MEMORY (Baddeley, 1990) Central executive (attentional control) Phonological store Visual-spatial sketchpad (Random letter generation) (Repetitive articulation) (Repetitive keying)

3. Concurrent Articulation and the Phonological Store (Peterson & Johnson, 1971)

4. WORKING MEMORY AND CHESS (Robbins, 1996) Primary task: recall of chess piece positions Secondary tasks: N None P articulate “the, the..” V execute 4x4 key pattern CE generate random letters Mean correct recall N P V CE

5. Instances of selective interference (e.g., Brooks, 1968) Imaging evidence (Jonides, 1995) –The n-back task 2-back: verbal: match letter identity Spatial: match location of dot in array Dorsolateral Prefrontal lights up: Left side for verbal task Right side for spatial task DISSOCIATING THE SKETCHPAD FROM THE LOOP MPFP + +

6. Prefrontal Activity Varies with Memory Demand Rypma, et al. (2002) 1, 3 or 6 letters in memory set

7. Low memory-demand activity limited to Ventrolateral Prefrontal Cortex High memory-demand also activates Dorsolateral Prefrontal cortex Differences are largest for high- performance subjects

8. WM ACTIVITY and LTM ENCODING Greater fMRI activity during WM trial correlated with: – better WM performance (Pessoa, et al. 2002 –Memory load for good performers (Rypma, et a., 2002) –Better subsequent LTM (Brewer, et al. 1988) Integrative WM tasks (e.g., item x location) correlated with: –Greater “remember” judgments –Specific areas of “coupling” of PFC and other cortical areas –Greater memory-contingent PFC effect for associative than item memory (Howland, 2005) –Baddeley’s “Episodic Buffer”?

9. WORKING MEMORY SPAN AND COGNITIVE PERFORMANCE Daneman & Carpenter (1980) –Reading Span, not digit span, correlates with reading comprehension The witness examined by the attorney… The evidence examined by the attorney… Engle et al. (1995) –Develop other “spans” (Operation Span) –Argue it’s not “capacity” but skill at controlling tasks and codes, inhibition, etc. –James’ “span of consciousness?”

10. Some Baddeley & Hitch 1974 trials A doesn’t follow BA B D precedes GG D X follows YX Y N doesn’t precede RR N Repeat 2,5,8,3 rapidly

11. Posner & Rossman 65 Demonstration Set 1: write down last two digits, and add one ARAP, e.g. 91/92/93 –2 6 4 5 7 3 8 1 –7 5 2 4 8 6 1 9 –1 3 2 4 5 7 6 8 Set 2: write down last two digits, and subtract 3 ARAP e.g. 91/88/85 –5 4 7 2 3 1 6 9 –7 1 2 8 9 4 3 5 –6 5 3 8 2 1 4 7 should be greater errors in Set 2, as difficulty of “work” in WM makes storage/refreshing of PL harder

12. N-back demo 0-back series (target is “S” –E D T W S V D D S G H R S 1-BACK (REPETITION) –N K Q Q F T L C C W T S S Q 2-BACK (LAG OF 2) –Q X F X W T T W T J L J N