Magnocellular involvement in flanked-letter identification relates to the allocation of attention

To verify the hypothesis that the magnocellular system is important to flanked-letter identification [Neuropsychologia 40 (2002) 1881] because it subserves attention allocation, we conducted three letter-naming experiments in which we manipulated magnocellular involvement (colour vs. luminance contrast) and prior information regarding target-letter location. Location information was provided through constant presentation at the same location (Experiment 1) or through auditory precueing (Experiments 2 and 3). In control conditions, either no (Experiments 1 and 3) or invalid (Experiment 2) location information was given. In line with the hypothesis, magnocellular input helped flanked-letter identification only when no prior location information was given. (C) 2004 Elsevier Ltd. All rights reserved.