Simple reaction time to chromatic changes along L&M‐constant and S‐constant cone axes

Abstract

The present study uses simple reaction time (RT) to examine the temporal response to chromatic changes of the red-green (L-2M) and yellow-blue (S-(LϩM

Postreceptoral chromatic-adaptation mechanisms in the red-green and blue-yellow systems using simple reaction times

“…8,21,22,[24][25][26][28][29][30] Both subjects had normal color vision (according to the Ishihara test, Pickford-Nicholson anomaloscopy, and Dichotomique Farnsworth 15D test) and normal stereopsis (according to stereo-fly tests). Observer MC was inexperienced while observer JA was highly experienced in VRT experiments.…”

“…To produce the stimuli with particular CIE-1931 coordinates and luminance, we used a modified calibration method of Post and Calhoun. 21,36,37 Observers were seated 70 cm from the CRT in a dark room and used a chin rest for head stabilization.…”

“…Simple reaction times, defined as the time that elapses from stimulus presentation until an observer's response is registered 19,20 (e.g., by pressing a key), offer the noteworthy possibility of exploring the relationship between visual latencies and their underlying physiological background for the whole eye-brain-hand system at suprathreshold conditions. 8,[19][20][21][22][23] Previous works have found that chromatic adaptation influences perceived contrast, producing selectivity changes along cardinal and intermediate color axes on the isoluminant plane. 8 Thus, it was found that mean visual-reaction times (VRTs) for contrast changes are sensitive to the chromatic-adaptation level evaluated in terms of Stiles's mechanisms or for both cardinal and noncardinal color axes on the isoluminance plane.…”

“…8 Thus, it was found that mean visual-reaction times (VRTs) for contrast changes are sensitive to the chromatic-adaptation level evaluated in terms of Stiles's mechanisms or for both cardinal and noncardinal color axes on the isoluminance plane. 8,21,22,24 In the present study, we use simple visual-reaction times (VRTs) as an alternative technique to study the temporal process in contrast detection after chromatic adaptation. We develop two levels of analysis.…”

“…Taking into account Piéron's law in terms of the RMS cone contrast scaled in threshold units, mean reaction times increased as the RMS cone contrast decreased. 19,21,22 Thus, if a single function account for all the data in the red-green direction under different adapting conditions, contrast detection will not be affected by the level of chromatic adaptation adopted, so that we can assume the existence of a single adaptive stage in the LϪM-cone system, presumably at the photoreceptor level. In the contrary case, if a single function fit each LϪM axis better under each adapting condition, contrast detection is influenced by the level of chromatic adaptation, and thus first-and secondsite adaptive processes should be considered within the red-green chromatic-opponent mechanism, the latter presumably associated at the postreceptoral level (analogously for the S-cone system).…”