The cone weightings obtained under the dark viewing conditions are shown as a function of age. The L,M,S cone weightings (columns 1–3) of the four chromatic mechanisms (YBR, YBG, RGY, RGB) that are silenced by unique red (row 1), green (row 2), yellow (row 3), and blue (row 4) are plotted as open symbols (see Eq 1–4 for details). Dashed lines (OBS) indicate the best fitting straight line to the data; solid lines (PRED) are the predictions based on the lens model (see Experimental Procedures). None of the observed slopes differs significantly from zero (p<0.05), indicating that the unique hue settings do not change with age. All slopes predicted from the lens model, however, differ from zero (p<0.001).