Go flash blinking lights at printed text right now

  1. Install a strobe light app on your phone (I used “strobe light tachometer” on ios.)

  2. Get some printed text like a nutrition label or a paper book

  3. Try to read the text with the light blinking at 5, 6, 7, 8, 9, 10, 11, 12, and 13 hz

  4. Report results. Was reading with one frequency much easier than the others? Easier than with normal constant light? Were they all terrible?


I just tried this and my eyes totally glazed over for everything except 12! I was feeling kinda tired and unfocused when I started and 12 was easier than baseline for me. Although annoying. I have incandescent lights in my kitchen. I did not turn them off. The phone light was brighter than the incandescent light.

Framerate stuff:

  • Phone flashlights are not meant to blink really fast (and max frequency is not documented) but the app seemed to work ok. I did notice an irregularity here and there but I don’t think that 12 being an even divisor of the flashlight frequency or something mattered.

  • If you have a 60hz monitor, then your screen can do a strobe light with 12, 10, 8.6, 7.5, or 6.7 hz. This is not very good resolution. A 120hz monitor should be good enough.

  • Would be better to test with a dedicated strobe light so this is not an issue.

More info about this experiment on first item here