The final set of points made by Mroczko-Wąsowicz concerns synesthesia, and in particular how the phenomenon presents an interesting complement to the sort of phenomenon we studied. When we were initially brainstorming the experiment we discussed what might happen if a synesthete were to wear the rotation gear. But that line of speculation never got past the brainstorming stage, since just doing it with ourselves proved enough of a challenge. While it has some significant differences from synesthesia, we did make an attempt to see whether the McCollough effect would adapt. But the subjective effect was very small, and didn’t last long enough into the protocol to get any data at the time when there might have been some adaptation.
Mroczko-Wąsowicz makes some fascinating points about how our study and synesthesia complement each other in interesting way that would be strong motivation for anyone following up on our study to try to include some synesthetes among the test subjects.