[e-khadem]

> Otherwise I'd assume they are making it up post-hoc.

You are right, in that this test might not live up to the highest of standards. But then there are variations in the details. For example one of my friends who happened to be a soccer player said more details about the ball. Other people described familiar objects such as their own kitchen table. You can also tell if someone is starting to think about the answers vs. when they are recalling from memory.

Overall, this method is often (IMO) a better indicator than the typical "apple test" as the context is more natural. Anecdotally the difference between the aphantasia group (incl. those who didn't know this condition existed) and the average response is just too large to ignore.

[bonoboTP]

I'm not so sure. People also describe their visual experience such as if it was camera-like. A rectangle window out of their ead with colors, like a photo/painting.

Perception and experience are very hard to describe. We constantly automatically fill in things that weren't observed or explicitly imagined. It requires conscious effort to notice how foveation and saccades work, the blind spot, the less vivid color perception the further we are from the center etc.