More on knowledge representation
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Announcements
– Homework #4 on web; due 3/19
– Exam II in class on 3/21
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Plan for today
– More on how imagery is like perception
– But not exactly
– And what about verbal representations?
– Exam prep
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Kosslyn’s block letter task
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How Images are Like Percepts
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More complex images (G vs. L) produced
longer latencies
X’s in early-stroke positions produced shorter
latencies than X’s in late-stroke positions (e.g.,
top vs. bottom of G)
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Images can be transformed
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Cooper’s study
– First get people to do rotation task
– Estimate their rotation rates
– Give figure to be imaged
– Say “Start rotating NOW”
– Show test stimulus
• normal, mirror-reversed
• Rotated to the angle predicted, a different angle
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Test stimulus’s angle impact reaction time?
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Images are generated in parts
– Star, G
Images can be inspected
– Exercises, eye movements
Images can be transformed
– Mental rotation continuous
– Mental rotation has momentum
Images can be inspected
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Scanning experiments (remember last time?)
Build this image and then tell what it is…
– Imagine capital “y”
– Put a small circle at the bottom
– Add a horizontal line halfway up
– Now rotate the figure 180 degrees
You have to inspect this image (and see
emergent property) to answer correctly
Steps executed 60%; Figure id’d 60%, given
steps executed correctly
Memory for Type of Visual Information
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Mandler & Richey
Procedure.
– Subjects viewed a series of pictures, each for 10
sec.
– Recognition task with 3 types of items
• Same - Pictures that were viewed in Part 1
• Type - Physical alteration -> change in meaning
• Token - Physical alteration -> same meaning
Token 7
Recognition of Same, token & type pictures
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80
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% Selected
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50
40
Type
30
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10
0
Correct
Token
Type
Results
Retention of Detail of Verbal Information 9
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Procedure
– Subjects listened to a story containing critical
sentences ( The missionary shot the painter)
– Subjects then asked to identify:
2.4
Reaction Time (Sec)
• If any of a set of sentences followed logically from the story
– The painter was shot by the missionary
– The painter shot the missionary.
– The missionary was shot by the painter.
– The missionary shot the painter.
Independent Variable: Delay to task (0 vs 2 min)
Dependent Measure:
2.2
Different Voice:
active - passive
2.0
1.8
Same Voice: active - active
1.6
1.4
1.2
– Reaction Time to I dentify Sentence.
Immediate
What kind of Information do we store?
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For both pictures and verbal information,
research suggests that we maintain meaningbased representations
Although details of visual and verbal may be
available initially, over time the details are lost
and the meaning remains
Delay
Propositional Representations
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People remember the underlying meaning not
the surface structure of verbal information
G Propositions: Smallest unit of knowledge that is
a separate assertion.
G Example
– The girl broke the large window on the porch.
Prop 1. The girl broke the window.
Prop 2. The window was on the porch.
Prop 3. The window was large.
Example 2.
The old car pulling the trailer climbed the steep
hill.
The car was old.
The car pulled the trailer.
The car climbed the hill.
The hill was steep.
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The ants ate the sweet jelly which was on the table. 15
The ants in the kitchen ate the jelly.
The ants in the kitchen ate the jelly which was on the
table.
The jelly was sweet.
The corresponding propositions that describe these
sentences.
1. The
2. The
3. The
4. The
ants ate the jelly. (eat, ants, jelly, past)
jelly was sweet. (sweet, jelly, past)
jelly was on the table. (on, jelly, table, past)
ants were in the kitchen. (in, ants, kitchen, past)
What did you remember?
Result
– Subjects were not able to discriminate between
old and new when the new were combinations
of the old propositions.
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Bransford & Franks Study
Procedure
– Subjects studied 12 sentences, two sets of four
propositions
Second set of sentences
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The rock rolled down the mountain and crushed the
tiny hut.
G The rock rolled down the mountain and crushed the
hut beside the woods.
G The tiny hut was beside the woods.
Propositions are:
G The rock rolled down the mountain.
G The rock crushed the hut.
G The hut was tiny.
G The hut was beside the woods.
Implication?
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 The ants ate the sweet jelly.
 The sweet jelly was on the table.
1. The ants ate the jelly. (eat, ants, jelly, past)
2. The jelly was sweet. (sweet, jelly, past)
3. The jelly was on the table. (on, jelly, table, past)
4. The ants were in the kitchen. (in, ants, kitchen, past)
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Do we represent information in
propositions?
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What we represent are the simple propositions.
Don’t remember the specific combinations of
propositions
In-class Exam II Next Thursday 3/21/02
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Covers Chapters 4- 8; lectures 2/19 - 3/19
Format like last time
– Mult choice, short answer, essay (choice)
Emphasis on big ideas; less on memorization
Evidence means empirical evidence
In-class Exam II Next Thursday 3/21/02
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All the memory stuff (4-8)
– Traditional model of memory
• Sensory store, Short term, Long term memory
• Features of each and evidence s upporting
– Baddeley’s Working memory model
• What it is (components) & how it differs from above
• Evidence for it
– Decay versus interference theory
• What is decay? Evidence
In-class Exam II Next Thursday 3/21/02
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In-class Exam II Next Thursday 3/21/02
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More on memory
– Decay versus interference theory (cont’d)
• What is Proactive/Retroactive interference
– Memory loss in amnesia
Nodes have activation (focus is source)
Links propogate activation (more links, weaker)
More total received activation, stronger retrieval
Effect of related info & linking to what you know
• Anterograde vs. retrograde
• Relating to theory of consolidation
• Dif ficulties and preserved processes in amnesics
– Multiple memory systems
– Other memory effects (related to above model)
• What they are and evidence (see above)
• Not all evidence that strong
• Depth /elaborateness of processing-> better memory
• Match btn encoding & retrieval -> better memory
• Intention to learn does NOT -> better memory
In-class Exam II Next Thursday 3/21/02
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Chapter 8 (esp lectures; I covered more)
– Internal mental representations
– Verbal vs. visual representations
• Paivio’s dual code theory and evidence (interference)
– Imagery as analogous to visual perception
• What is the argument? Evidence from mental rotation,
image scaling, image scanning
– Imagery is like seeing (evidence, mostly today)
• Images are generated in parts
• Images can be inspected
• Images can be transformed (mental rotation)
More on memory
– PDP model of memory
• Main features & how does it work (interactive)
• Relating it to human memory effects
– Network of activation model
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In-class Exam II Next Thursday 3/21/02
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Chapter 8 (esp lectures; I covered more)
– Mental representations not exact pictures
• Visual scenes as schemas
• Verbal material represented as propositions
• Identify a proposition
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