A non-informative cue (C) elicits an inhibition of manual reaction time (MRT) to a visual target (T). We report an experiment to examine if the spatial distribution of this inhibitory effect follows Polar or Cartesian coordinate systems. C appeared at one out of 8 isoeccentric (7o ) positions, the C-T angular distances (in polar coordinates) were 0º or multiples of 45º and ISI were 100 or 800ms. Our main findings were: (a) MRT was maximal when C- T distance was 0o and minimal when C-T distance was 180o and (b) besides an angular distance effect, there is a meridian effect. When C and T occurred in the same quadrant, MRT was longer than when T and C occurred at the same distance (45o ) but on different sides of vertical or horizontal meridians. The latter finding indicates that the spatial distribution of the cue inhibitory effects is based on a Cartesian coordinate system.

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