CONTRAST DISCRIMINATION FUNCTION - SPATIAL CUEING EFFECTS

The effects of spatial cuing were measured for discriminating between an increment and a decrement on a target's pedestal contrast. Discrimi nation thresholds measured in the absence of a spatial cue were always higher than corresponding thresholds measured in the presence of a sp atial cue, except when pedestal contrast was near zero. Uncued discrim ination thresholds rose monotonically with pedestal contrast; cued dis crimination thresholds formed a dipper function of pedestal contrast. A spatial-uncertainty model incorporating a nonlinear transducer produ ced similar results. (C) 1997 Optical Society of America.