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  • I'm looking at this on my phone in a dark room, and if I zoom in or out, the text moves faster than the background. Spooky.

    • Same thing happens with those old alarm clocks with LED 7 segment displays.

      I think it's the difference between rods and cones on the retina. Rods are more sensitive to light but do not see colour. That's what you use in the dark. I suspect they are also slower to react to light (probably because they need to gather enough over time to make an image). So since the lighter text is bright enough to be seen by the cones, the reaction time is quicker so it looks like it's moving independently.

      Anyway that's my theory and I'm sticking to it. :P

      • That similar effect happens with some 7-segment displays because they actually flicker very fast (either didn’t bother to add an AC rectifier if it’s wall power, or it uses PWM to regulate the brightness). You can see it if you point a camera at them. The visual cortex makes it appear like it’s a continuous light but that illusion is destroyed as soon as the light moves. (Pretty sure this is the same effect which makes a moving image on CRT monitors appear smoother at low frame rate than LCD monitors.)

        I don’t know for sure but I don’t think there’s any significant reaction time difference between rods and cones in different light levels. There is a difference in how long they take to adjust to different light conditions (IIRC rods take longer to adjust to darkness but can achieve much higher sensitivity in darkness).

    • Does your phone have an OLED display? My old phone had noticeably slow reaction time on dark pixels when the brightness was turned all the way down IIRC. Might be what’s happening here.

    • ...uh...static input moving is a sign of being on the schizophrenia spectrum, otherwise known as visual hallucinations...

11 comments