Short-wavelength cones contribute to achromatic sensitivity.

Visual thresholds for flicker detection and light detection were measured for white and yellow flickering targets superposed on a white adapting field. The flicker frequency was set so that flicker detection thresholds always exceeded the light detection thresholds. The difference between the two types of thresholds was found to be smaller for yellow targets than for white targets. The most likely explanation of this result is that short-wavelength cones contribute to achromatic sensitivity at low temperal frequencies.