FASTER THAN THE EYE CAN SEE - BLUE CONES RESPOND TO RAPID FLICKER

Flickering lights that are detected by the blue cones of the human vis ual system fuse to yield a steady sensation at much lower rates of fli cker than do lights that are detected by the red or green cones. Yet, although blue-cone-detected lights flickering at 30-40 Hz appear to be steady, they are still able to interact with red- or green-cone-detec ted flickering lights to produce clearly detectable beats in the form of an amplitude modulation of the red-or green-cone flicker. Thus the blue cones produce a viable high-frequency flicker signal, as do the r ed and green cones, but one that is normally lost before it reaches se nsation.. The temporal-frequency response for the blue-cone beat inter action is similar in shape to the temporal-frequency response for dire ctly detected red- or green-cone flicker. When measured through the sa me pathway (which we identify as the luminance pathway, since it is ab le to transmit high-frequency flicker), the response of the blue cones seems to be as fast as that of the other cones.