Check out the linked articles below.
I thought using pupil dilation to confirm lack of mental visualization was cool and didn't see it on the discussion boards.
I asked my wife (has moderate ability to visualize) to cover her eyes then uncover them to get a sense of how much here eyes dilate from dark to light. Then I asked her to visualize looking at the sun then visualize entering a dark room (with her eyes open). She could dilate her eyes on command. And I could tell her when she was visualizing a sun and when she was in a dark room!
I've got Aphantasia (multisensory). We tried the same with me. No change as expected.
Its a really cool way to prove someone a lack of mental imagery.
Link 1:
https://www.unsw.edu.au/newsroom/news/2022/04/windows-to-the-soul-pupils-reveal-aphantasia-the-absence-of-visual-imagination#:~:text=The%20pupils%20of%20those%20with%20aphantasia%20dilated%20when%20they%20imagined,not%20in%20a%20visual%20way.%E2%80%9D
Link 2:
https://www.medicalnewstoday.com/articles/the-minds-eye-pupil-size-may-be-indicator-of-aphantasia
