Only one person is known to be able to voluntarily change the size of their pupil

[Biscuit2021]

In a study published in the International Journal of Psychophysiology in 2021, researchers observed a man who can apparently change the size of his pupil on command. Currently, he is the only individual known to be able to do this.

 

[supermax_thelion1]

That’s mind-blowing! It makes you wonder what else the human body is capable of that we haven't even discovered yet. Imagine the level of control and focus it must take to consciously change something that’s usually automatic. Who knows, maybe this could lead to more discoveries about mind-body connections!