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Abstract:
Lou (Perception 28, 519-526, 1999) reported that in a display
with disks of two colors, presented away from fixation, directing
attention to disks of one color facilitated their filling-in by a
gray background, compared to unattended disks of another color. The
goal of our study was to test whether this effect would hold for
other stimulus-types and attentional manipulations, using
psychophysical methods. In a first experiment, human subjects
fixated away from a gray square surrounded by dynamic texture.
Attention was directed towards the square by having subjects
perform a Vernier task on line segments inside the square.
Attention was directed away from the square by performing the
Vernier task elsewhere in the visual field. No effects of attention
on filling-in were observed (N=4). We then replicated and expanded
Lou's findings, using figures presented on a dynamic texture
background. Attentional selection of a set of figures by their
color or shape facilitated their filling-in. We conclude that while
Lou's findings may not depend on stimulus attributes, the method
used to direct attention may be critical. In our experiments,
attention was directed to a single figure rather than a set of
figures, and attention was directed using a Vernier task. We are
exploring these and other differences between Lou's and our
experiments to enhance our understanding of interactions between
attention and filling-in.
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