Chromatic: Chromatic Thresholds across the Life Span

Description Usage Format Details References Examples


Thresholds for equiluminant chromatic differences as a function of age along 3 axes in the CIE xy chromaticiy diagram. Data were obtained using a spatial, two-alternative forced-choice paradigm. Responses were obtained from preverbal observers using forced-choice preferential looking.




A data frame with 511 observations on the following 4 variables.


a numeric vector giving the log base 2 age of each observer


a numeric vector giving the age of each observer in years


a numeric vector giving the threshold modulation in distance along the axis from the ‘white’ point in CIE xy space along the axis being tested


a factor with levels Deutan Protan Tritan giving the nominal axis in CIE xy space along which the threshold was measured. The terms refer to the confusion lines through the ‘white’ for each of three types of congentially dichromatic observer. In the CIE xy-plane, these correspond to projections of axes that isolate modulations in each class of human cone photoreceptor.


Equiluminant modulations along the ‘Protan’ and ‘Deutan’ axes projected in the CIE xy-plane are not cone-isolating. However, in the experiment, the chromatic modulations were presented mixed with dynamic, random luminance noise that had been shown to mask luminance components of the stimulus, thus favoring detection by chromatic pathways.


Knoblauch, K, Vital-Durand, F, Barbur, JL (2001). Variation of chromatic sensitivity across the life span. Vision Research., 41, 1:23–36.



MPDiR documentation built on May 2, 2019, 5:54 p.m.