a Barplot shows % fixation duration on the relevant portion of the passage (normalized by height) when participants answered the factual question correctly vs. not. Error bars denote the mean ± s.e.m. (n = 53, 13 tasks for correct vs. wrong responses). b Example of fixation heatmap for easy factual task; c difficult factual task. d–f Scatterplots showing different metrics as a function of task difficulty. d Time to answer the question in seconds (includes time spent reading the question and the passage); e number of fixations on the passage; f percentage time on relevant region, computed as the % total fixation duration on the relevant portion of the passage (normalized by height). Statistical correlation reported is the Spearman’s rank correlation coefficient (n = 10 tasks); two-tailed one sample t-test. The confidence band represents the bootstrapped 68% confidence interval.