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This seems to be the case even when I'm simply using my eyes to watch neighboring car wheels turn!


Do eyes all interpret at the same frequency or will some people arrive at the time frame where the wheel seems to be stationary while another still sees movement from the wheel?


@xTheBHox I think one difference between this slide and the case you said is that camera here is like an intermediate media, which has its own sampling rate. So the wagon wheel effect you see here is not exactly the same as what you see on the road.


This is an interesting problem. Inspired from this question, I am thinking about what makes a video more real to human


@xTheBHox I would bet that you've never seen this effect during the daytime: in daylight, you'll essentially perceive an image of the wheel integrated over some interval of time, which will just result in a blur. At nighttime (e.g,. when driving in a tunnel) you may see this effect because the lights themselves are on an AC current, which means they're oscillating brighter/darker at some fixed rate. When the rate of the wheel lines up with the oscillations of the light in just the right (or wrong!) way, you get aliasing. (An extreme version of this same phenomenon would be watching motion under a strobe light.)


@nrauen As mentioned to @xTheBHox, this particular phenomenon really has to do with synthetic lighting rather than the human eye. But certainly there are other important perceptual phenomena (such as color perception) that vary from individual to individual. We'll talk about this in our lecture on color.