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Abstract:
Using a Posner cueing paradigm and a perceptual illusion that
altered the perceived distance between locations within a scene,
Robertson, Kim and Barnes (1998) demonstrated that the facilitatory
components of attention are guided by perceived distance rather
than actual distance. The present study examines whether inhibitory
components of attention may also be guided by perceived space. On
each trial subjects were presented with a cartoon scene that
included a variant of the Muller-Lyer illusion. Within the scene
there were two parallel lines of equal length separated by a
distance equal to the length of the lines. Depth cues were used to
produce an illusion that one of the lines was longer than the
other. We randomly cued an end of one line using noninformative
exogenous cues, followed by a target that could appear at either
the same location as the cue (valid), at the uncued end of the cued
line (invalid-within) or at either end of the uncued line
(invalid-between and invalid across). Reaction times to the cued
location were slower than to the uncued locations and did not
differ with regard to the perceived length of the lines. These
results suggest that the inhibitory mechanisms of attention may be
guided more by space as it is measured on the screen, and not by
space as it is perceived.
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