COLOR FROM INVISIBLE FLICKER - A FAILURE OF THE TALBOT-PLATEAU LAW CAUSED BY AN EARLY HARD SATURATING NONLINEARITY USED TO PARTITION THE HUMAN SHORT-WAVE CONE PATHWAY

The Talbot-Plateau law fails for flicker detected by the short-wavelen gth-sensitive (S) cones: a 30-40 Hz target, flickering too fast for th e flicker to be resolved, looks more yellow than a steady target of th e same average intensity. The color change, which is produced by disto rtion at an early compressive nonlinearity, was used to reveal a sligh tly bandpass S-cone temporal response before the distortion site and a lowpass response after it. The nonlinearity is probably a 'hard' nonl inearity that arises because the S-cone signal is limited by a respons e ceiling, which the mean signal level approaches and exceeds as the S -cone adaptation level increases. The nonlinearity precedes the combin ation of flicker signals from all three cone types. (C) 1998 Elsevier Science Ltd. All rights reserved.