You'll find that movies and console games can run lower 24FPS and get away without being noticed, because of the distance and edge blur.
This is why monitors now all come with backlights, it greatly reduces this flickering effect. Depending on how smooth the edges of the animation is, the human brain will still register the previous few frames with the one it sees, calculating differences and ignoring slight variations. Mostly it's ignored by the human brain, cats and dogs for example would notice it more. It's the flickering effect which annoys the human eye, as the frame flips to the next.
Persistence of vision is the phenomenon of the eye by which an afterimage is thought to persist for approximately one twenty-fifth of a second on the retina. However, at the same time, a health young standard human eye can perceive and detect drops below 48 FPS and even noticable changes even up to 120 FPS.
The human eye doesn't see in FPS (Frames Per Second).
