> But as the twitter thread shows, lots of people can do that. Only seen a few videos there but they all seem to have a distinct-but-not-fully opening and clos

> But as the twitter thread shows, lots of people can do that. Only seen a few videos there but they all seem to have a distinct-but-not-fully opening and closing of the eyelids happening at the same time - when the eyelids close, the pupil grows; when they open, it shrinks. Which suggests a certain amount of autonomic reaction to changing light conditions rather than controlling the pupil itself? I guess you'd have to demonstrate it without any eyelid movement to control for that.