Title
Differences in fixations between grasping and viewing objects
Author
Brouwer, A.M.
Franz, V.H.
Gegenfurtner, K.R.
TNO Defensie en Veiligheid
Publication year
2009
Abstract
Where exactly do people look when they grasp an object? An object is usually contacted at two locations, whereas the gaze can only be at one location at the time. We investigated participants' fixation locations when they grasp objects with the contact positions of both index finger and thumb being visible and compared these to fixation locations when they only viewed the objects. Participants grasped with the index finger at the top and the thumb at the bottom of a flat shape. The main difference between grasping and viewing was that after a saccade roughly directed to the object's center of gravity, participants saccaded more upward and more into the direction of a region that was difficult to contact during grasping. A control experiment indicated that it was not the upper part of the shape that attracted fixation, while the results were consistent with an attraction by the index finger. Participants did not try to fixate both contact locations. Fixations were closer to the object's center of gravity in the viewing than in the grasping task. In conclusion, participants adapt their eye movements to the need of the task, such as acquiring information about regions with high required contact precision in grasping, even with small (graspable) objects. We suggest that in grasping, the main function of fixations is to acquire visual feedback of the approaching digits. © ARVO.
Subject
Vision
Eye movements
Eye-hand coordination
Fixation locations
Grasping
Visuo-motor
adaptation
adaptive behavior
adult
comparative study
eye fixation
eye movement
female
finger
hand strength
human
male
physiology
psychomotor performance
thumb
time
vision
Adaptation, Physiological
Adult
Eye Movements
Feedback, Psychological
Female
Fingers
Fixation, Ocular
Hand Strength
Humans
Male
Psychomotor Performance
Thumb
Time Factors
Vision, Ocular
Young Adult
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DOI
https://doi.org/10.1167/9.1.18
TNO identifier
181254
ISSN
1534-7362
Source
Journal of Vision, 9 (1), 1-24
Article number
18
Document type
article