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Abstract:
Abstract: Using event-related brain potentials, we examined
whether individual differences in hemispheric utilization bias
influence the degree and manner in which a hemisphere is biased to
attend to contralateral space. Studies of hemi-neglect patients
have suggested that the cerebral hemispheres have competing biases
to direct attention to contralateral space, with the left
hemisphere (LH) having a stronger bias than the right hemisphere
(RH). Additionally, individuals have characteristic biases to
utilize a particular hemisphere for processing information, which
can also bias attention contralaterally. We predicted that these
effects would jointly influence hemispheric control of spatial
attention, such that LH-biased compared to RH-biased individuals
would display a stronger rightward attentional bias. Participants
made choice responses to target stimuli presented to one hemisphere
while distractors were simultaneously presented to the opposite
hemisphere. In Experiment 1, LH-biased subjects had larger N2pc
effects in Attend-LVF than Attend-RVF, consistent with a rightward
attentional bias. LH-biased subjects also had larger P1 attention
effects in Attend-LVF than Attend-RVF, suggesting that they
employed an early selection strategy to compensate for their
rightward attentional bias. Experiment 2 replicated these findings
and found that LH-biased subjects modified their early selection
strategy on a trial-by-trial basis. We conclude that hemispheric
utilization bias enhances a hemisphere's intrinsic contralateral
attentional bias, which individuals may attempt to modulate when it
is detrimental to task performance.
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