Cognitive Effort & Pupillometry
during Narrative Comprehension
Jeremy G. Grant
Behavioral Neuroscience Program & Biology Department, Andrews University
Faculty Sponsor: Dr. Karl G. Bailey
INTRODUCTION
RESULTS
DISCUSSION
During the 5 seconds after the 6th sentence...
• Contrary to the predictions of previous research,
the average response times in the blocked-view
stories did not differ from those in the
unblocked-view scenarios (t = 0.09, p = 0.925)
METHODS
Average z-score
According to the perceptual availability hypothesis, an
A) Average pupil dilation activity increases in the stories
event within a story that blocks the protagonist’s view of a
where the protagonist’s view becomes blocked
salient object will decrease a reader’s ability to recall
B) Average pupil dilation activity decreases in the stories
information about that object when questioned. Recalling
where the protagonist’s view remains unblocked
information about an occluded object presumably extends
producing a significant difference (t = 2.59, p = 0.013)
response time because it involves increased cognitive load.
Pupillary responses are used to identify increases in
Blocked view
Unblocked view
cognitive effort during perceptual tasks. Using
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pupillometry, we sought to establish a timeline for the
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changes in cognitive effort that occur during visual
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occlusion, and thereby identify when perceptual availability
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impacts narrative comprehension.
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Average Z-score
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1. Forty-three undergraduate students listened to 16
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narrated stories while viewing an illustration of each
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story’s setting. Each story was 7 sentences long:
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Time (ms)
• The 4th sentence of each story mentioned a target detail
within the protagonist’s imaginary line of sight.
During the 5 seconds after the question…
• The 6th sentence mentioned an event that blocked the
C) Average pupil dilation activity increases in both the
protagonist’s view of the target detail in 4 stories, and
stories where the protagonist’s view becomes blocked
left the target detailed unblocked in 4 stories.
and the stories where the protagonist’s view remains
• 8 control stories did not contain an occlusion event.
unblocked; (t = 0.15, p = 0.879)
2. While listening to the stories, a head-fixed eye tracker
Blocked view
Unblocked view
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recorded the pupil dilations of each subject’s left eye.
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3. After each story, the subject answered a yes-or-no
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question about the target detail.
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CONCLUSIONS
• Pupil dilations increase when a listener
perceives an occlusion event in a story,
suggesting an increase in cognitive effort.
• Pupil dilations increase when retrieving
information about an object in the story—
regardless of changes to the protagonist’s view of
the object.
• According to previous literature, these results
suggest that the situational model is built
immediately during the narration.
• Unlike previous studies, this study introduced a
visual representation of the narrated stories;
subjects may have used the illustration as an
external aid in building and accessing the
situation model. This may explain the lack of
difference between blocked and unblocked
responses.
REFERENCES
Ferreira, F., Bailey, K. G., & Ferraro, V. (2002). Good-Enough
Representations in Language Comprehension. Current Directions in
Psychological Science, 11(1), 11-15.
Horton W. S., Rapp, D. N. (2003). Out of sight, out of mind:
Occlusion and the accessibility of information in narrative
comprehension. Psychonomic Bulletin & Review, 10(1), 104-110.
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Piquado, T., Isaacowitz, D., & Wingfield, A. (2010). Pupillometry as a
measure of cognitive effort in younger and older adults.
Psychophysiology, 47(3), 560–569.
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O'Regan, J.K. (1992). Solving the "real" mysteries of visual
perception: The world as an outside memory. Canadian Journal of
Psychology/Revue Canadienne de Psychologie, 46(3), 461-488.