When you watch a film, for example, projected on film, you're watching 24 frames, which are still images every second. And your brain is looking effectively at still images. And then you're using the persistence of vision to stitch those still images together to create the illusion of motion. And this activates beta cycles in your brain. Whereas video was using refresh rates and scan lines. And this activated alpha cycles in your brain, which is why people were able to absorb hours and hours of television very easily.