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Abstract:
Abstract: Evidence suggests there may be two different
attention mechanisms: one that selects locations and one that
selects objects. In 1994, Tipper et al. demonstrated that reflexive
orienting could be object-based. In order to distinguish cued
objects from cued locations, Tipper et al. non-predictively cued
one of two boxes as they traveled along an imaginary path around
the fixation point. Inhibition of return (IOR) was observed at the
cued object's new location, indicating object-based orienting.
However, the objects in these displays always maintained their
positions relative to one another. Thus, IOR may have appeared to
follow the cued object EITHER because attention was allocated to
the cued object, OR because attention was operating on relative
rather than absolute locations. In the present study, object-based
IOR was investigated within a similar paradigm that included
various types of motion. Cue and target positions were held
constant, but objects moved either as if they were linked or as if
they were separate. Displays containing "linked" objects (fixed
spatial relations) were compared to displays in which the spatial
relations among objects were not strictly maintained. When Tipper's
object-based IOR findings could be replicated, it appeared that IOR
was greater in displays in which the objects moved in a linked
fashion, thereby maintaining their relative positions as they
moved. The role of objects in defining spatial reference frames for
attention will be discussed with the results.
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