Nieves J L, Valero E M, Garcia J A, Romero J, 1999, "Do chromatic sensitivity thresholds reveal red - green dominance in grating-detection tasks?" Perception 28 ECVP Abstract Supplement
Do chromatic sensitivity thresholds reveal red - green dominance in grating-detection tasks?
J L Nieves, E M Valero, J A Garcia, J Romero
We have tested the influence of colour vision mechanisms in chromatic-grating detection thresholds. The stimuli were isoluminant red - green (r/g) or blue - yellow (b/y) sine-wave gratings generated on a CRT colour monitor. Chromatic contrast values were selected along the r/g axis (deutan line) or y/b axis (tritan line) according to Boynton's model; in addition, two intermediate axes were selected by adding the same r/g and y/b contrast values. Along each axis, we measured the threshold contrast for sixteen spatial frequencies from 1.0 to 4.0 cycles deg-1. Each threshold was the mean of two measurements obtained with a three-interleaved 2AFC staircase procedure. The test stimulus appeared in one of two time intervals and the other interval was blank. On one hand, the results showed a significant increase of b/y sensitivity for both intermediate axes. This apparently indicates a strong dominance of the r/g mechanism over this range of spatial conditions. On the other hand, the results derived from r/g sensitivity were also in agreement with the aforementioned r/g dominance. For one of the observers, this dominance seemed to be so strong that the addition of some amount of b/y contrast to the r/g contrast did not modify the r/g sensitivity threshold.
These web-based abstracts are provided for ease of seaching and access, but certain aspects (such as as mathematics) may not appear in their optimum form. For the final published version of this abstract, please see
ECVP 1999 Abstract Supplement (complete) size: 1478 Kb