Although mind wandering during reading is known to be affected by text difficulty, the nature of this relationship is not yet fully understood. To examine this issue, we conducted an experiment in which participants read non-fiction texts that varied along five levels of difficulty under naturalistic conditions. Difficulty levels were determined based on Flesch–Kincaid Grade Levels and verified with Coh–Metrix indices. Mind wandering was measured with thought probes. We predicted that text difficulty and mind wandering have a U-shaped (i.e., quadratic) relationship. Contrary to our expectations, but in line with some prior studies, mind wandering linearly increased with text difficulty. Additionally, text interest moderated the effect of text difficulty on mind wandering. Finally, mind wandering was associated with worse performance on a comprehension test. Together, our findings extend previous work by showing that (a) a linear relationship between difficulty and mind wandering exists during common page-by-page reading of pre-existing texts and that (b) this relationship holds across a broad range of difficulty levels.

虽然已知阅读过程中的走神会受到文本难度的影响，但这种关系的性质尚未完全理解。为了检验这个问题，我们进行了一项实验，参与者在自然条件下阅读不同难度级别的非小说文本。难度级别根据 Flesch-Kincaid 等级水平确定，并使用 Coh-Metrix 指数进行验证。走神是用思想探针测量的。我们预测文本难度和走神有一个 U 形（即二次）的关系。与我们的预期相反，但与之前的一些研究一致，思维游荡随着文本难度线性增加。此外，文本兴趣缓和了文本难度对走神的影响。最后，走神与在理解测试中表现较差有关。总之，我们的研究结果扩展了以前的工作，表明（a）在对预先存在的文本进行常见的逐页阅读过程中存在难度和走神之间的线性关系，并且（b）这种关系适用于广泛的难度级别.