[docfort]

There is research on humans showing that we can perceive at 500 Hz. There are devices that try to simulate a color by modulating a single LED (no color filter) and they don’t work on humans until you go past around 1 kHz.

https://www.nature.com/articles/srep07861

[svara]

Yes, that's what I was referring to. If you have an edge flickering at a high frequency and perform a saccade (fast eye movement) over the edge, your retina will be exposed to the edge at regularly spaced intervals. So the motion will not appear smooth. That's what they call a 'flicker artifact' and I called a 'stroboscope-like effect'.

Importantly though, this is not us humans detecting 500 Hz flicker itself, quite the opposite -- the reason the artifact is visible is that our retina is not sensitive to fast motion, it integrates over a period of time in which the edge appears to be in multiple locations.