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Abstract:
Physiological studies and behavioral dissociations between
object identification and object localization abilities in patients
have supported the notion of separate neuroanatomical pathways for
the processing of objects and locations in the visual system.
Accumulating evidence suggests that attention may be volitionally
allocated to locations and/or objects under different
circumstances. The role of objects in reflexive attention and the
distinction between location-mediated as opposed to pure
object-based attention mechanisms are less well understood. In the
past, Posner cueing paradigms with non-predictive cues have been
used to asses the reflexive orienting of attention to spatial
locations. Little concern, however, has been given to the objects
(usually empty boxes) that are used to mark potential target
locations in these paradigms. We have manipulated the shapes of
these location-markers in a standard cueing paradigm to examine the
influence of object identity on reflexive attentional orienting.
Object and location cueing effects were separately identified and a
significant interaction between object and location cueing was
observed. Interestingly, object shape influenced the inhibitory
component of reflexive orienting, but only when the cued shape was
present at the cued location supporting a view of object-based
attention that is location-mediated, at least for exogenous
attentional mechanisms.
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