This exact issue is why we ended up replacing our old toilet.

I think this happens because of words sounding similar: charteuse (yellow green) sounds like puce (dusty pinky red) which looks a lot like mauve (dusty purply pink). Then the brain decides that all three are green, because the first word in the chain of words & meanings dominates.

I think that the humidity level in my house would indicate otherwise. We have a dehumidifier that runs if the humidity goes over 60 percent and it doesn't run at all when the heat is on in winter, even with 2 small humidifiers running on low to prevent dangerous levels of dryness (without humidifiers we get nosebleeds, cracked lips and severely dry, chapped skin).

True, but with forced air or electric heat, you're also drying the air. Running a small humidifier on a low setting can make a huge difference in perceived warmth while the relative humidity is still quite low.