Attention-referenced visual representations: Evidence from impaired visuallocalization

Spatial representations in the visual system were probed in 4 experiments i nvolving A. ii., a woman with a developmental deficit in localizing Visual stimuli. Previous research (M. McCloskey et al., 1995) has shown that A. H. 's localization errors take the form of reflections across a central vertic al or horizontal axis (e.g., a stimulus 30 degrees to her left localized to a position 30 degrees to her right). The present experiments demonstrate t hat A. H.'s errors vary systematically as a function of where her attention is focused, independent of how her eyes, head, or body are oriented, or wh at potential reference points are present in the visual field. These result s suggest that the normal visual system constructs attention-referenced spa tial representations, in which the focus of attention defines the origin of a spatial coordinate system. A more general implication is that some of th e brain's spatial representations take the form of coordinate systems.