Earlier quoted context omitted.
I think I've read the article differently to you. It does not say that the afterimage is a test . In fact it calls it an illusion. > This afterimage illusion, while a product of perception, serves as a bridge to understanding visualization The way that illusion works is simple. You expose your eye to green light without moving your gaze (stare at the dot). The green receptors in your eye become tired in the receptor…
In a sense I agree with you that this is the intent of the article. I find this kind of laughable because I do not consider myself to have aphantasia (I can visualize things just fine) but the afterimage test is not even vaguely representative of how I visualize things. But you can see people on this very thread claiming that they in fact do perceive visualization that way, and can overlay it on their physical vision…
> Can you superimpose onto your actual visual field an arbitrary imagined image? Not just imagine what it would look like, but see it
This is your only question. No I cannot is my answer.
I don't know if its because I am aphantasic (which I definitely am) or not or if a phantasic would be able to do that either. Just because they can see something in their minds does not mean that they could superimpose it over the visual world they were seeing. I can only guess at this, but 'minds eye' is like another dimension. You can imagine things there, and your brain can simply focus on them instead of the signals you are getting from your optic nerves, or your auditory sensations, or the feelings from your butt as you sit on the chair.
I do not see things in my minds eye but I can conceptualise them perfectly well. I basically never remember if I have any dreams, perhaps I do not, but I do remember waking as if from a dream and realising that I had had a significant recognition moment, as if I had experienced a thing before. Perhaps I had a non-visual dream.