There is another interesting effect that becomes apparent in
Figure 8b. In this experiment, the results obtained by both the human observers and CIWaM observer do not lie on the line joining the reference ring color and the first inducer color. A priori we would expect the final test color to move toward the first inducer color (as in the previous condition) and the results to lie on the line joining these two colors. However, for all configurations, the results are shifted to the right of the test-inducer triangle, in the direction of the positive
l channel. These results (and the model's behavior) were initially unexpected by the authors, who anticipated the colored points of the plot to be aligned toward the 1st inducer, not to be shifted toward the right side. However, it is possible to qualitatively explain these results again bearing in mind
Assumption 3. In the
s chromatic channel, the reference ring has high surround contrast energy because of the different
s values between the 1st and 2nd inducer rings. However, in the
l chromatic channel, the first and second inducer rings have the same value, which means that the reference ring is on a uniform “
l” background (see image next to the
l channel). A uniform background on the
l channel yields null surround contrast energy for the reference ring in that channel, which by means of
Assumption 3 implies that on the
l channel contrast is high (i.e., it shifts away from the first inducer) and assimilation is low (i.e., it shifts toward the first inducer). Because of that, the
l chromaticity value of the reference ring moves away from that of the first inducer (it has a higher
l value). On the other hand, on the
s channel the surround contrast energy is high, inducing assimilation (i.e., the reference–test rings move toward the 1st inducer). The combined effects on both channels is that the resulting reference ring chromaticity becomes higher on the
l channel
and on the
s channel (i.e., it shifts toward the top right corner of the figure), which is different to what was expected from the previous results.