Coming Up:
Read:
The Lost Mariner by Oliver Sachs
Repressed Memories by Elizabeth
Loftus
Overview of Memory
• Atkinson-Shiffrin Model
RETRIEVAL
ATTENTION
Sensory
Signals
Sensory
Memory
Short-Term
Memory
Long-Term
Memory
REHEARSAL
Recap: Short-Term memory
• Span of “seven plus or minus two” must be
qualified by rate of speech
• Primacy and recency effects influence which
items are best recalled
• Interference depends in part on semantic
meaning
Coding in STM
• How is information coded in STM? What is the
“file format”?
Coding in STM
• Clues about coding in STM:
– # of items stored in STM depends on rate of speech
Coding in STM
• Clues about coding in STM:
– # of items stored in STM depends on rate of speech
– phonological similarity effect: similar sounding words
are harder to store/recall than different sounding
words
Coding in STM
• Clues about coding in STM:
– # of items stored in STM depends on rate of speech
– phonological similarity effect: similar sounding words
are harder to store/recall than different sounding
words
– “counting backwards” prevents mental rehearsal
Coding in STM
• Clues about coding in STM:
– # of items stored in STM depends on rate of speech
– phonological similarity effect: similar sounding words
are harder to store/recall than different sounding
words
– “counting backwards” prevents mental rehearsal
What does this suggest about the “format” of STM?
Coding in STM
• It seems that information can be stored in a
linguistic or phonological form
Coding in STM
• It seems that information can be stored in a
linguistic or phonological form
Must it be stored this way?
Delayed Match-To-Sample
Remember the locations of the letters
Delayed Match-To-Sample
A
Q
P
Delayed Match-To-Sample
Delayed Match-To-Sample
Was there a letter at the location of the star?
Coding in STM
• It is also possible to “keep in mind” nonverbal information, such as a map
Are there two different STM systems?
A Modular Approach to STM
Central
Executive
Articulatory
Loop
Visuospatial
Sketchpad
Introduces the notion of “Working Memory”
because emphasis is on performing mental
operations on the information encoded
A Modular Approach to STM
Central
Executive
Articulatory
Loop
Visuospatial
Sketchpad
Experiment 1 in the article by Lee Brooks
demonstrates a double dissociation between
Articulatory Loop and Visuospatial Sketchpad
Working Memory “Modules”
• Lee Brooks: interference between different
representations in STM (Experiment 1)
– Memory Representation
• verbal task: categorize words in a sentence
• spatial task: categorize corners in a block letter
– Response Modality
• verbal response: say “yes” or “no”
• spatial response: point to “yes” or “no”
Working Memory “Modules”
• Verbal Task: indicate if each word is or is not a
noun
– “I went to the store to buy a loaf of bread.”
–N N N N Y N N N Y N Y
Working Memory “Modules”
• Spatial Task: indicate if each corner points
outside
Y
Y
F
Y
N
Working Memory “Modules”
• In both tasks the information needed must be
maintained (represented) in working memory
Working Memory “Modules”
• Response Modalities:
Verbal
Say: “yes” “no” “no”
Spatial
Point to: Y or N
Y
Y
Y
Y
Y
N
N
N
N
N
Working Memory “Modules”
• Both response modalities also engage working
memory
Working Memory “Modules”
• Prediction:
– There should be interference when response
modality and task representation engage the same
module
– if there is only one kind of module, then there should
be interference between every pairing of
representation to response
Working Memory “Modules”
• result: a cross-over interaction (double dissociation)
Performance
Verbal Representation
(categorize words)
Spatial Representation
(categorize corners)
Spatial
Verbal
Response Modality
Working Memory “Modules”
• Interpretation:
– supports notion of modularity in Working Memory
(visuospatial sketchpad / articulatory loop work
independent of each other)