I have aphantasia. The reason this experiment works is because someone with aphantasia will logically think about what they're being asked, but since they're not really "picturing" it, they won't have any answers about details. Color, type, and size of the ball? I have no idea, that information wasn't relevant to my mental checklist. For me, it really does work like a checklist. My brain supplies exactly zero imagery. For some people it's more like a spectrum, where they might be able to have a hazy picture with minimal details.
But aphantasia is 100% real. It's just hard for people to believe it because it's so foreign to the way they're used to thinking, in the same way it sounds unbelievably exhausting to me that regular people are constantly creating movies in their heads.
Sorry to be pedantic but the word is "precedent"