Filling-in of a vertical band with different colors. Figure 6 differs from the previous one only in having two colors. Well, I see the central portion of the band as being narrower and quite indistinct, filled-in more by the background than as a continuous band, just like Fig. 5. It seems to have a number of characteristics. It seems automatic, it occurs immediately, it is consistent from one presentation to another and it also seems consistent for different individuals.
Most people report the same perception for a given figure.
This suggests it does not depend on learning or individual idiosyncracies. That suggests it is not a higher-level cognitive process depending on our assumptions about the way things should look. Here, Ss report that the central dot disappears rather than being filled-in with a dot that preserves the pattern. Filling-in with an array of dots. Actually, what I see is that the central dot and the one below it disappear and are filled in with the background when fixating the X in Fig 7.