Please use this identifier to cite or link to this item: http://hdl.handle.net/2445/44177
Title: People favour imperfect catching by assuming a stable world
Author: López i Moliner, Joan
Keil, Matthias S.
Keywords: Percepció visual
Psicomotricitat
Temps de reacció (Psicologia)
Visual perception
Psychology of movement
Reaction time (Psychology)
Issue Date: Apr-2012
Publisher: Public Library of Science (PLoS)
Abstract: The visual angle that is projected by an object (e.g. a ball) on the retina depends on the object's size and distance. Without further information, however, the visual angle is ambiguous with respect to size and distance, because equal visual angles can be obtained from a big ball at a longer distance and a smaller one at a correspondingly shorter distance. Failure to recover the true 3D structure of the object (e.g. a ball's physical size) causing the ambiguous retinal image can lead to a timing error when catching the ball. Two opposing views are currently prevailing on how people resolve this ambiguity when estimating time to contact. One explanation challenges any inference about what causes the retinal image (i.e. the necessity to recover this 3D structure), and instead favors a direct analysis of optic flow. In contrast, the second view suggests that action timing could be rather based on obtaining an estimate of the 3D structure of the scene. With the latter, systematic errors will be predicted if our inference of the 3D structure fails to reveal the underlying cause of the retinal image. Here we show that hand closure in catching virtual balls is triggered by visual angle, using an assumption of a constant ball size. As a consequence of this assumption, hand closure starts when the ball is at similar distance across trials. From that distance on, the remaining arrival time, therefore, depends on ball's speed. In order to time the catch successfully, closing time was coupled with ball's speed during the motor phase. This strategy led to an increased precision in catching but at the cost of committing systematic errors.
Note: Reproducció del document publicat a: http://dx.doi.org/10.1371/journal.pone.0035705
It is part of: PLoS One, 2012, vol. 7, num. 4, p. 1-8
Related resource: http://dx.doi.org/10.1371/journal.pone.0035705
URI: http://hdl.handle.net/2445/44177
ISSN: 1932-6203
Appears in Collections:Articles publicats en revistes (Cognició, Desenvolupament i Psicologia de l'Educació)

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