Article

Several lines of evidence show that visual perception is altered at the locus of
visual attention: detection is faster, performance better and spatial resolution
increased. It is however not known whether attention can affect visual perception
further away from its locus. In the present study, we specifically question
whether and how visual attention influences spatial perception away from its
locus, independently from any saccadic preparation. We use a landmark task in
which subjects have to estimate the location of a bisection stimulus relative to
two landmark stimuli 15 degrees apart, while fixating one of them. This task is
combined with a highly demanding discrimination task performed on one of the two
landmarks. This allows us to test for the effect of spatial attention allocation
on distance perception, as measured by the subject estimation of the landmarks
midpoint. We show that the estimated midpoint is displaced towards the
attentional locus, both when attention is instructed on the central landmark or
on the peripheral landmark. These results suggest an overrepresentation of space
around the attentional locus that can affect perception up to 8 degrees away, and
question the existence of an objective spatial representation. They are in line
with reports of spatial distortion in hemineglect patients while they strikingly
contrast with the spatial compression reported around the time of saccadic
execution.
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Langue : ANGLAIS