Eye Gaze Behavior at Turn Transition: How Aphasic Patients Process Speakers' Turns during Video Observation
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
The human turn-taking system regulates the smooth and precise exchange of speaking turns during face-to-face interaction. Recent studies investigated the processing of ongoing turns during conversation by measuring the eye movements of noninvolved observers. The findings suggest that humans shift their gaze in anticipation to the next speaker before the start of the next turn. Moreover, there is evidence that the ability to timely detect turn transitions mainly relies on the lexico-syntactic content provided by the conversation. Consequently, patients with aphasia, who often experience deficits in both semantic and syntactic processing, might encounter difficulties to detect and timely shift their gaze at turn transitions. To test this assumption, we presented video vignettes of natural conversations to aphasic patients and healthy controls, while their eye movements were measured. The frequency and latency of event-related gaze shifts, with respect to the end of the current turn in the videos, were compared between the two groups. Our results suggest that, compared with healthy controls, aphasic patients have a reduced probability to shift their gaze at turn transitions but do not show significantly increased gaze shift latencies. In healthy controls, but not in aphasic patients, the probability to shift the gaze at turn transition was increased when the video content of the current turn had a higher lexico-syntactic complexity. Furthermore, the results from voxel-based lesion symptom mapping indicate that the association between lexico-syntactic complexity and gaze shift latency in aphasic patients is predicted by brain lesions located in the posterior branch of the left arcuate fasciculus. Higher lexico-syntactic processing demands seem to lead to a reduced gaze shift probability in aphasic patients. This finding may represent missed opportunities for patients to place their contributions during everyday conversation.
Date Issued
2016-08-31
Date Acceptance
2016-08-31
Citation
Journal of Cognitive Neuroscience, 2016, 28 (10), pp.1613-1624
ISSN
0898-929X
Publisher
Massachusetts Institute of Technology Press (MIT Press)
Start Page
1613
End Page
1624
Journal / Book Title
Journal of Cognitive Neuroscience
Volume
28
Issue
10
Copyright Statement
© 2016 Massachusetts Institute of Technology
Subjects
Experimental Psychology
1109 Neurosciences
1701 Psychology
1702 Cognitive Science
Publication Status
Published