Discourse Representation
in the Right Hemisphere
Now you see it…Now you don’t
Debra L. Long
Center for Mind and Brain
Departments of Psychology
University of California, Davis
University of Central Lancashire
The RH Syndrome
„
„
„
Tangential in conversation
Excessively literal
Integration deficit
– Failure to make inferences
– Poor use of structural cues in integration
– Failure to revise misinterpretations
Outline
„
„
Nature of discourse representation
Discourse representation in the two hemispheres
– Explicit text information
– Relevant semantic information
„
„
Item priming in recognition
Experiments
– Explicit text concepts
„
Experiments 1 & 2
– Relevant semantic information
„
Experiment 1
– Manipulations that change how discourse is represented
„
Experiments 3-6
Memory for Discourse
„
Propositional network (text base)
– Network of explicit ideas
– Concepts structured by means of
syntactic and semantic relations
„
Situation Model
– Referential
– Explicit information integrated with
relevant world knowledge
Discourse Representation
in the Hemispheres
„
„
Does memory for discourse in the two
hemispheres reflect the distinction between
a text base and a situation model?
Do the LH and RH represent
– The propositional structure of sentences?
– Semantic information relevant to the discourse
model?
„
„
Context-appropriate senses of ambiguous words?
Inferences about the topics of sentences?
Item Priming in
Recognition
„
Read a set of passages
– Round after round, the visitor tried to find his
opponent’s weakness. When the fencing
instructor blew his whistle, the visitor lowered
his foil.
„
Recognition test
–
–
–
–
–
garbage
fencing
instructor
foil/whistle
visitor
The townspeople were amazed...all the
buildings had collapsed except the mint…the
architect had foreseen the danger because the
structure withstood the natural disaster.
Condition
Prime
Target
Same-proposition
Different-proposition
disaster
danger
structure
structure
Appropriate-associate
Inappropriate-associate
buildings
buildings
money
candy
Appropriate-topic
Inappropriate-topic
structure
structure
earthquake
breath
Experiment 1
„
Goal
– Assess the nature of discourse representation in the two
hemispheres
„
Method
– Participants
„
Right-handed, native English, undergraduates
– Materials & Procedure
„
„
Two-sentence passages & priming pairs
Study-test trials
– Study set of passages, presented centrally
– Divided VF recognition test: priming pairs + fillers
„ Primes presented centrally
„ Targets presented in LVF or RVF
Long & Baynes (2002)
J. of Cognitive Neuroscience
Experiment 1: Propositional Priming
The townspeople ....building... mint. ... the architect had foreseen
the danger because the structure withstood the natural disaster.
RT (ms) to "No" Responses
1100
Same
1000
(disaster-structure)
900
Different
(danger-structure)
800
700
LVF/RH
RVF/LH
Visual Field
Long & Baynes (2002)
J. of Cognitive Neuroscience
Experiment 1: Associate Priming
The townspeople ....building... mint. ... the architect had foreseen
the danger because the structure withstood the natural disaster.
RT (ms) to "No" Responses
1100
Appropriate
1000
(buildings-money)
900
Inappropriate
(buildings-candy)
800
700
LVF/RH
RVF/LH
Visual Field
Long & Baynes (2002)
J. of Cognitive Neuroscience
Experiment 1: Topic Priming
The townspeople ....building... mint. ... the architect had foreseen
the danger because the structure withstood the natural disaster.
RT (ms) to "No" Responses
1100
Appropriate
1000
(structure-earthquake)
Inappropriate
900
(structure-breath)
800
700
LVF/RH
RVF/LH
Visual Field
Long & Baynes (2002)
J. of Cognitive Neuroscience
Experiment 2
„
The RH represented explicit text
concepts, but did not show intrasentential structure
– Is the RH sensitive to sentential
boundaries?
While the hunter (who was wearing an orange
vest) stalked the pheasant, the deer ate leaves
in the meadow. the birds sang as they roosted
in the trees and watched the creatures below.
Condition
Prime
Target
Same-proposition
pheasant
hunter
Different-proposition
deer
hunter
Different-sentence
birds
hunter
Different-passage
sight
hunter
Experiment 2
„
Goal
– Assess the organization of explicit text concepts
in the RH
„
Method
– Materials & Procedure
„
„
Two-sentence passages & priming pairs
Study-test trials
– Study set of passages
– Divided VF recognition test: priming pairs + fillers
„ primes presented centrally
„ targets presented in the LVF or RVF
Long, Baynes, & Prat (2005)
Brain & Language
Experiment 2: Propositional Distance
While the hunter (who was wearing an orange vest) stalked the
pheasant, the deer ate leaves in the meadow. The birds sang as
they roosted in the trees and watched the creatures below.
RT (ms) to "No" Responses
1000
Same
(pheasant-hunter)
900
Different
(deer-hunter)
800
Sentence
(birds-hunter)
700
Passage
600
LVF/RH
RVF/LH
(sight-hunter)
Visual Field
Long, Baynes, & Prat (2005)
Brain & Language
Summary
„
Only the LH has a representation with
propositional structure
– Consistent with the importance of syntax
in deriving propositions
„
Both hemispheres are sensitive to
context-appropriate semantic
information
Individual Differences in
Discourse Representation
„
Poor comprehenders construct
adequate sentence representations,
but poor situation models
– Fail to make elaborative inferences
– Fail to integrate ideas across sentences
– Show propositional and associate priming,
but no topic priming
Experiment 3
„
Goal
– Examine discourse representation in the
hemispheres as a function of
comprehension skill
„
Method
– Undergraduates received the NelsonDenny Reading Comprehension Test
– Materials & procedure from Long &
Baynes (2002)
Prat, Long, & Baynes (2006)
Brain & Language
The townspeople were amazed...all the
buildings had collapsed except the mint…the
architect had foreseen the danger because the
structure withstood the natural disaster.
Condition
Prime
Target
Same-proposition
Different-proposition
disaster
danger
structure
structure
Appropriate-associate
Inappropriate-associate
buildings
buildings
money
candy
Appropriate-topic
Inappropriate-topic
structure
structure
earthquake
breath
Experiment 3: Propositional Priming
The townspeople ....building... mint. ... the architect had foreseen
the danger because the structure withstood the natural disaster.
LVF/RH
RVF/LH
RT (ms) to “Yes” Responses
900
750
600
450
400
150
0
20
40
60
80
ND Score
Same (disaster-structure)
Different (danger-structure)
100
0
20
40
60
80
100
ND Score
Prat, Long, & Baynes (2006)
Brain & Language
Experiment 3: Associate Priming
The townspeople ....building... mint. ... the architect had foreseen
the danger because the structure withstood the natural disaster.
LVF/RH
RVF/LH
RT (ms) to “No” Responses
900
750
600
450
400
150
0
20
40
60
80
100
ND Score
Appropriate assoc. (buildings-money)
Inppropriate assoc. (buildings-candy)
0
20
40
60
80
100
ND Score
Prat, Long, & Baynes (2006)
Brain & Language
Experiment 3: Topic Priming
The townspeople ....building... mint. ... the architect had foreseen
the danger because the structure withstood the natural disaster.
LVF/RH
RVF/LH
RT (ms) to “No” Responses
900
750
600
450
400
150
0
20
40
60
80
100
ND Score
Appropriate topic (structure-earthquake)
Inappropriate topic (structure-breath)
0
20
40
60
80
100
ND Score
Prat, Long, & Baynes (2006)
Brain & Language
Experiment 4
„
Goal
– Assess the representation of explicit text
concepts in the RH as a function of
comprehension skill
„
Method
– Undergraduates received the NelsonDenny Comprehension Test
– Materials & procedure from Long, Baynes,
& Prat (2005)
While the hunter (who was wearing an orange
Vest) stalked the pheasant, the deer ate leaves
in the meadow. the birds sang as they roosted
in the trees and watched the creatures below.
Condition
Prime
Target
Same-proposition
pheasant
hunter
Different-proposition
deer
hunter
Different-sentence
birds
hunter
Different-passage
sight
hunter
Experiment 4: Propositional Distance
While the hunter (who was wearing an orange vest) stalked the
pheasant, the deer ate leaves in the meadow. The birds sang as
they roosted in the trees and watched the creatures below.
LVF/RH
RVF/LH
RT (ms) to “Yes” Responses
900
750
600
450
400
150 0
20
40
60
ND Score
80
Same prop (pheasant-hunter)
Different prop (deer-hunter)
100
0
20
40
60
ND Score
80
100
Different sent. (birds-hunter)
Different pass. (sight-hunter)
Prat, Long, & Baynes (2006)
Brain & Language
Summary
„
Discourse representation in the LH was
unaffected by comprehension skill
–
–
–
„
Propositional distance effect
Associate priming
Topic priming
Discourse representation in the RH was
related to skill
– Structured representation in poor
comprehenders
– Topic priming increased as comprehension skill
decreased
Experiment 5
„
Goal
– Examine discourse representation in the
hemispheres as a function of task difficulty
„
Method
– Materials & procedure from Long, Baynes, & Prat
(2005)
– Manipulated memory load during study trials
„
„
Low load Æ 1 digit
High load Æ 4 digits
– Digit recall followed by recognition test
Experiment 5: Propositional Distance
While the hunter (who was wearing an orange vest) stalked the
pheasant, the deer ate leaves in the meadow. The birds sang as
they roosted in the trees and watched the creatures below.
Low Load
High Load
1000
RT (ms) to "Yes" Responses
RT (ms) to "Yes" Responses
1000
900
800
700
600
900
800
700
600
LVF/RH
RVF/LH
Visual Field
Same prop (pheasant-hunter)
Different prop (deer-hunter)
LVF/RH
RVF/LH
Visual Field
Different sent. (birds-hunter)
Different pass. (sight-hunter)
Experiment 6
„
Goal
– To determine whether RH propositional priming
was enhanced by the influence of load at
encoding or emphasis on accuracy at retrieval
„
Method
– Materials & procedure from Long, Baynes, & Prat
(2005)
– Manipulated retrieval instructions
„
„
Equal emphasis on speed an accuracy
Accuracy emphasized more than speed
Experiment 6: Propositional Priming
While the hunter (who was wearing an orange vest) stalked the
pheasant, the deer ate leaves in the meadow. The birds sang as
they roosted in the trees and watched the creatures below.
Speed & Accuracy Emphasized
Accuracy Emphasized
1000
RT (ms) to "Yes" Responses
RT (ms) to "Yes" Responses
1000
900
800
700
600
900
800
700
600
LVF/RH
RVF/LH
Visual Field
Same prop (pheasant-hunter)
Different prop (deer-hunter)
LVF/RH
RVF/LH
Visual Field
Different sent. (birds-hunter)
Different pass. (sight-hunter)
Summary
„
„
LH discourse representation reliable
across materials, readers, tasks
RH discourse representation
– Has propositional structure in poor
comprehenders
– Less sensitive to topic information in good
than in poor comprehenders
– Strongly influenced by task demands
RH Variability
„
„
„
RH language processing is a weak
reflection of LH processing
RH provides added computational
power when comprehension is difficult
RH plays an important role in memory
and/or decision-related processes
involved in many tasks
Acknowledgements
„
„
„
„
Kathleen Baynes, Ph.D.
Chantel Prat, Ph.D.
Clinton Johns
Amy Lincoln
National Institutes of Health (NIDCD)
National Science Foundation