| |
Abstract:
Spatial repetition blindness is a failure to detect a
simultaneous repetition of a to-be-reported feature (Kanwisher,
Driver, & Machado, 1995, Cognitive Psychology). Patient R.M.,
who has Balint's Syndrome as a consequence of bilateral
occipital-parietal lesions, showed a severe deficit in detecting
repetitions of stimuli that differed in color. R.M. viewed
nine-element search arrays that contained blue distractors with
either a single odd-colored target (red or green) or two
odd-colored targets (both red, both green, or one of each color).
His task was to report the number of targets present in the
display. When a single target was present, he responded correctly
98% of the time. When two targets were present he responded
correctly 93% of the time when the two targets were red and green,
but only 6% of the time when both targets were the same color. The
same pattern was observed when R.M. was asked to report what he saw
rather than the number of targets. In light of R.M.'s other
deficits (Robertson, Treisman, Friedman-Hill and Grabowecky, 1997,
Journal of Cognitive Neuroscience), this failure to detect
simultaneous repetition appears to stem from his inability to bind
features to a spatial location. The relationship between these
results and other reports of repetition blindness in patients and
neurologically healthy individuals will be discussed.
|
