PSYCH 240 LEC 10 (WORKING MEMORY)

How thinking involves working memory: Raven's Progressive Matrices

• Task for IQ test

  • See 3×3 grid of abstract patterns with the last cell missing, pick the option that completes it, through looking across the rows and columns.

• Example of having crucial memory through

  • Storing then delay occurs

  • Retrieval

How thinking involves working memory: Mental arithmetic

• Solving multi-step math problems in your head

• Hold intermediate results and store in WM while you do the next step

Individual differences: measure of working memory span

• WM SPAM

  • Defined as the # of final words you can remember

• Task:

  • Read series of sentences

  • Recall Final word of each sentence in order

• Results:

  • Process sentence to deduce grammatical, store, retrieve words = not passive remembering

Individual differences: Raven's

1. Raven’s scores worse for older people

2. Raven’s scores better when WM is good

• Scores are worse when WM is bad (independent of age)

• Correlation of age and WM but not causational

Individual differences: aging

• Raven’s score worse in older population

• Raven’s score better in younger population

Individual differences: working memory

• Raven’s score better if WM is good

• Raven’s score worse if WM is bad

• HIGH WM = Better at text comprehension

Interference: random number generation and syllogistic reasoning

Task done simultaneously

• Categorical Syllogism

  • 2 premises and a conclusion, each stating a relationship between categories using “all,” “some,” or “no,” such as “All A are B; all B are C; therefore all A are C.” If premise true must see if conclusion is T or F

• Random Number Generation (WM task)

  • No repeating #s too

Result: WM interferes with reasoning, they cannot do these tasks simultaneously

Interference: Reading comprehension

Task

• Read sewer as sewer the first time

• Then reinterpret based on surrounding words

Result

• HIGH WM = Better at text comprehension

Evidence for WM/LTM distinction: Dissociations

• Double Dissociations

• Lesion Studies

  • Lesions in Area A (K.F.) → System A (WM) → Task 1 depends on WM

  • Lesions in Area B (H.M.) → System A (LTM) → Task 1 depends on LTM

• Tasks depend on it’s specific system

Anterograde amnesia (LTM disorder) vs. working memory disorder

• H.M = Anterograde Amnesia

  • Cannot remember events after brain injury

  • Common damage = Hippocampus

• K.F. = Working Memory Disorder

  • Normal LTM

  • Impaired WM

Evidence for WM/LTM distinction: Serial position curve

• U-Shaped Curve

• Try to remember as much words as possible

Sig:

• Helps infer they are separate systems

Serial position curve: primacy effect vs. recency effect

Primacy Effect

• Start of the list

• Test after 30 sec delay suggest is LTM

  • Maintained

• Slower rate of presentation

  • Increases

  • Due to repeated rehearsal

Recency Effect

• End of the list

• Test after 30 sec delay suggest is STM

  • Decreases

Double dissociation logic: as applied to lesions

Double dissociation logic: behavioral dissociations

Double dissociation logic: and neuroimaging

Phonological loop: buffer and rehearsal

• Baddeley's 3-part model

• 
  

Visuospatial sketch-pad

Baddeley's 3-part model

• WM component devoted to visual imagery and spatial processing

• Info. can enter buffer via

  • Direct visual perception

  • From LTM

• Info treated as precept (to be scanned, rotated, enlarged)

Central Executive

• Chief Executive Officer (CEO)

• Baddeley's 3-part model

  • Supervises attention

  • Planning/Coordination

  • Monitoring

Phonological loop evidence: Phonological coding: acoustic confusion (acoustic similarity effect)

Phonological loop evidence: what about visual similarity or similarity in meaning?)

Phonological loop evidence: Articulatory suppression

Phonological loop evidence: Phonological storage capacity: chunks

Phonological loop evidence: Time effects: word length

Phonological loop evidence: speed of speech

Speed of speech: WM span is large for: words that are pronounced quickly

Speed of speech: people who speak quickly

Speed of speech: and languages where words can be pronounced quickly

Phonological loop PET evidence: rehearsal process activates left hemisphere (Broca's area) and not right frontal

Visuospatial sketchpad: Behavioral double dissociation: Brooks letter-scanning task or sentence task coupled with pointing responses or vocal responses

Visuospatial sketchpad: Pattern of interference

Visuospatial sketchpad (PET evidence): PET evidence: visuospatial WM activates right frontal lobe and not left

Visuospatial sketchpad (PET evidence): PET double dissociation between phonological loop and visuospatial sketch-pad

Central executive: frontal lobe syndrome: perseveration

Central executive: distractibility