It's also worth mentioning the most basic phenomenon of the movies: the reason why 24 still frames (or more) sequentially presented to the eye over a period of 1 second, are interpreted by the mind as motion.

wiki: Persistence of Vision.

The phrase covers several phenomena, and the jury is still out as to which is the actual 'cause'. The Phi  phenomenon, Beta Movement or the 3 phenomena that are part of the Lilac Chaser, are all part of the PoV.

Frame rates as low as 10 - 12 frames per second can also be interpreted as continuous motion - depending on  the  time that the frame is held stable in vision and the 'blank' time it is being exchanged for the next frame.

Frames rates lower than 10 - 12 start to be seen as individual images or rather as 'jerkiness'. Frame rates in the 6 - 8 can trigger epilepsy (strobe lights or the sun flashing hrough tres while speeding on a motorway can do the same). Alpha waves are electromagnetic oscillations in the brain of 8 - 12 Hz. (there's a neuronal pacemaker). Beta rhythms in the brain are from 12 - 30 Hz, Gamma waves average about 40 Hz (but range from 25 - 100 Hz. Theta waves are 6 - 10 Hz.

Strangely, the early 20th C audiences for e.g. Charlie Chaplin movies never saw the speeded up motion that is now iconic for 'silent movies'. The lack of standards at the time for filming and projections speeds (until the mid '20s the cameras and projected were hand-cranked), along with the cost of early nitrate film stock, meant that shooting speeds of 12 frames per second were common - and the projectionists would attempt to match these speeds in showing the film. As motors were added, a frame rate of 16 fps became standard.

By the time the 'silent movies' were revisited, the technology for presenting the movies at their original frame rates were no longer generally available. Thus they were run at faster frame rates of fixed speed projectors.

You can't be me, I'm taken