  As noted in the previous subsection, there are more perceptually distinguishable shades between red and blue than there are between green and yellow, which would make red-green inversion behaviorally  detectable.[16]  And there are yet further asymmetries. Dark yellow is brown (qualitatively different from yellow), whereas dark blue is blue (see figure 6). Similarly, desaturated bluish-red is pink (qualitatively different from saturated bluish-red), whereas desaturated greenish-yellow is similar to saturated greenish-yellow. Again, red is a “warm” color, whereas blue is “cool”—and perhaps this is not a matter of learned associations with temperature (see Hardin 1997, 297–7). In any event, there is clearly scope to resist the claim that one of Palmer’s three inversions would be behaviorally  undetectable.[17]