1. Things you think are happening now could actually have happened up to 80 milliseconds ago.
Your brain basically edits the world around you to make simultaneous events appear simultaneous, even though the actual signals take different amounts of time to reach your brain.
3. As long as two related things happen within 80 milliseconds of each other, your brain can match them up.
For example, if the soundtrack of a film matches the pictures within 80 milliseconds, you’ll perceive them as being in sync. If its over 80 milliseconds out, though, you’ll notice.
This isn’t because your brain can’t tell time to that precision. It can, it just chooses not to, and by doing so helps you make sense of the world.
4. We know this thanks to a series of experiments conducted by neuroscientist David Eagleman and his lab that show how your brain puts events together.
In one illusion, called the flash-lag effect, a flash of light and a moving object appear to be offset from each other, yet are actually in the exact same place. This is because when your brain tries to match perception with reality, sometimes it gets it wrong.
A 2000 paper by Eagleman and neuroscientist Terrence Sejnowski, published in the journal Science, proposed an explanation for the flash-lag effect which says whatever happens in the 80 milliseconds after the flash determines how you perceive it.