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Abstract:
In previous experiments we tested detection of intrasaccadic
position changes for stationary and translating objects. Detection
was very high for displacements in translating in comparison to
stationary objects. One explanation we proposed for this 'moving
object superiority' was a mechanism with high temporal and spatial
resolution optimally adapted to keep track of translating objects
even across saccades. This description of the data was tested by
introducing a postsaccadic blank (objects were not visible for 220
ms after the saccade) for both types of objects. It was previously
found that blanking increases detection rates for static objects
(Deubel, Schneider, & Bridgeman, 1996). For translating objects
we expected the opposite, since we hypothesised that the immediate
postsaccadic presence of the translating object was crucial for
adequate sampling of spatial information and thus for high
detection. The data showed indeed that blanking (compared with
non-blanking) increased detection of position changes for static
objects, whereas detection for displacements for translating
objects deteriorated. Our data suggest that for transsaccadic
perception of spatial information different mechanisms are at work
for stationary and moving objects. Especially for a translating
object, fast postsaccadic access to object or motion information
seems vital for accurate detection of changes in its
motion-path.
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