alt Hacker NewsIf I listen to 100 NDEs and in 50 they travel through a tunnel like this or somehow go through space, and in 2 from stone age cultures they travel in a manner apt to their everyday experience and it has those things in common I think it's a fine hypothesis that what they have in common is the nature of what's happening. And in 48 they didn't experience this stage.
Have you read any pop neuroscience book? There are common experiences that can be generated by one or another kind of brain-wrong. You sort of acknowledged this already when you mentioned DMT. If you poke somebody in specific parts of the brain you can get illusions of changing size, shadowy figures, mirth, and other delightful errors. We also interpret things very eagerly, like the "night hag" phenomenon where being unable to sense one's own breathing turns into an illusion of something sitting on your chest. That's another worldwide cross-cultural concept, by the way, but there is no night hag, there's just human physiology.
So, bright lights and tunnels. Shared human visual neurological glitches. Heard of "tunnel vision"? That's a real medical condition, which can be caused by blood loss, adrenaline, or low oxygen.