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Abstract:
Abstract: Lavie (1995) has recently demonstrated that
irrelevant visual distractors are nonetheless perceived under
situations of low perceptual load. Here we tested recent claims
that the efficiency of visual selection in such cases (i.e. the
extent to which target selection can be maintained despite having
perceived distractors) depends on the availability of frontal
control functions such as working memory (WM, e.g. Lavie, 2000). We
used fMRI to assess the extent to which WM load determined
processing of irrelevant face distractors. Participants had to
categorize target names, presented concurrently with distractor
faces (or with no distractor faces), whilst performing a WM task
with either high or low load. As predicted by Lavie for situations
of low perceptual load, distractor related activity was found in
the fusiform face area (ffa, see Kanwisher et al. 1997). Load in
the WM task had a main effect in inferior and medial frontal cortex
(area 9/47/46) as expected. More importantly, distractor related
activity in ffa was significantly greater in high vs low WM load.
These findings support our claim that the efficiency of visual
selection depends on frontal cognitive control functions such as
WM.
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