TL;DR: Longer Sections of Text Increase Rates of Unintentional Mind-Wandering

The prevalence of the acronym tl;dr (“too long; didn’t read”) suggests that people intentionally disengage their attention from long sections of text. We studied this real-world phenomenon in an educational context by measuring rates of intentional and unintentional mind-wandering while undergraduate student participants (n = 80) read academic passages that were presented in either short sections of text (one sentence per screen) or relatively long sections (2–6 sentences per screen). We found that participants were significantly more likely to unintentionally disengage their attention while reading the longer sections of text, whereas intentional mind-wandering rates were equivalent across short and long sections of text. The difference in unintentional mind-wandering rates suggests that section length may serve as a cue that people use to assess the cost-benefit tradeoffs involved in attending to (or disengaging from) text. We conclude that instructors should avoid presenting electronic reading material in long sections of text.