| |
Abstract:
We investigated whether temporal aspects of orienting of
attention may affect a previously found hemispheric asymmetry in
the ability to ignore distractors in the unattended field
(Passarotti, Banich and Chaudhari,1998). On each trial participants
saw hierarchical figures and responded either to the global or to
the local aspects of a target figure. On unilateral trials only one
target was presented in one visual field, whereas on bilateral
trials a target and a distractor were presented simultaneously, one
in each visual field. The target visual field was cued either 0, 50
or 100 ms prior to the presentation of the figures. Confirming
previous results, we found that only for the right hemisphere
attentional demands modulate the degree of interference from
distractors in the unattended field. Interference was greater when
attentional demands were relatively high (i.e., when the target was
inconsistent at the global and local levels) than when attentional
demands were relatively low (i.e., when the target was consistent
at the global and local levels). Although temporal aspects of
cueing affected local processing, they did not affect the
hemispheric asymmetry in the ability to ignore distractors in the
unattended field. Furthermore, for both hemispheres, when global
processing was required, bilaterally redundant trials were as fast
as unilateral trials. But for local processing, bilaterally
redundant trials were slower than unilateral trials.
|
