It happens to everyone, but some people experience it constantly. You read a sentence. You reach the end. You have no idea what it said. So you go back. You read it again. This time you get part of it. You continue — and two sentences later, you're back to the top of the paragraph.
The usual explanation is distraction. Your mind wandered. But that's a description, not an explanation. Why did it wander? What broke the loop?
"Re-reading is your brain telling you the signal got lost. The question is where."
Three things that break the loop
First: line length. When a line extends beyond your comfortable peripheral span, your brain spends cognitive effort tracking your position on the line rather than processing its content. This is why print columns are narrower than they could be.
Second: ambient visual noise. Everything on the page that isn't the sentence you're on competes for your attention. Multiple columns, images, adjacent text, margin notes — all of it is processed peripherally, even when you're trying to focus.
Third: pace mismatch. If you're reading slower than your natural processing speed, your working memory has time to fill with irrelevant thoughts. If you're reading faster than your processing speed, the words pass before the meaning forms.
What happens in the right environment
All three of these problems are format problems. They're caused by the presentation of the text, not by your brain's capacity to understand it. RSVP eliminates line length as a variable. It eliminates peripheral visual noise. It allows you to calibrate pace precisely.
The re-reading stops. Not because you've trained yourself, but because the conditions that were causing it are no longer present. The loop stays intact because there's nothing to break it.
That's what PageBurn gives you. A closed loop. One word at a time. The signal doesn't get lost because there's no room for it to get lost.