On topic, though, I tried it, and changing what I'm focused on doesn't change my pupil size. But maybe I wasn't going far enough? I just looked in a mirror, focused on a spec of dust on the mirror, then changed focus to the image of something behind me, and my pupils didn't change at all.
I can do that.
Usually I ask a friend to count up to 3 and then on 3 I dilate the pupils immediately.
> For example, researchers already knew that just thinking about the sun could constrict the pupils and that thinking of a dark room or mentally calculating something could dilate them, […]
Apparently, it is about changing the pupil’s size without any physical or mental stimulus.
I can't walk while urinating. If I've started urinating and realize that I should be standing a little bit farther forward or back or to the side I have to stop, move, and restart.
I asked once on some other forum if others have the same restriction and everyone claimed they can easily walk while urinating.