All right, I've been reading faster and faster due to dduck's suggestion (thank you, dduck). And I've come up with an analogy - tell me what you think.

Analogy:

I play the trombone. (Hopefully someone here is musical, and gets this.) On the trombone you can do a glissando or a slide where you play, and as you're playing you just let the slide of the trombone drop. You play all the notes that are in that slide (there are seven), but you don't distinguish any particular note. I think that reading fast is like doing a glissando: you read all the words, though you don't necessarily distinguish any one word. It just sort of blurs together, yet you understand the blur.

I hope this made sense. I just wanted to share.