Seeing Through Your Eyelids -- Spreading Motion
When I close my eyes and wave my hand before my face, I seem to see motion. I think this isn't just the caver illusion (the sense people sometimes have, in complete darkness, that they can see their hands move), because the effect seems much stronger when I face toward a light source, and I can see a friend's hand in the same way. In some sense, I am seeing through my eyelids. This shouldn't be too surprising: Most people report being able to see the sun through their eyelids. Such a thin band of flesh is easily penetrated by light. I discussed this stuff a bit in a May post.
Although I was pretty confused in my May post, I'm finding more consistency now with directional and occlusion effects. If I move my hand slowly from one side to the other, I can locate the position of the movement as to the right or the left. If I face a bright light source and move my head, I can track the rough direction of the source. If I raise an occluding object between my face and my moving hand -- a newspaper, say, held eight inches before my face -- the impression of movement is much lessened. (Any sense of motion that remains might really be just the caver illusion.)
The oddest effect is when I slightly lower the occluding object, so that the tips of my fingers are not occluded, but the rest of my hand and arm is. Once again I have a vivid experience of motion -- but not as though located just at the top of the visual field. The motion seems to spread down the field, almost to the bottom, as though the newspaper were entirely removed, but somewhat less vivid. In fact, it seems to me that the primary effect of moving the newspaper up and down is increasing and decreasing the vividness of the sense of motion. The change in the visual extent of the motion experience appears relatively minor.
As far as I'm aware, this spreading of perceived motion when the eyes are closed has never been remarked on in the perception and consciousness literature. I wonder if others experience the same thing...?