Subjective impressions do not mirror online reading effort: concurrent EEG-eyetracking evidence from the reading of books and digital media

Abstract

In the rapidly changing circumstances of our increasingly digital world, reading is also becoming an increasingly digital experience: electronic books (e-books) are now outselling print books in the United States and the United Kingdom. Nevertheless, many readers still view e-books as less readable than print books. The present study thus used combined EEG and eyetracking measures in order to test whether reading from digital media requires higher cognitive effort than reading conventional books. Young and elderly adults read short texts on three different reading devices: a paper page, an e-reader and a tablet computer and answered comprehension questions about them while their eye movements and EEG were recorded. The results of a debriefing questionnaire replicated previous findings in that participants overwhelmingly chose the paper page over the two electronic devices as their preferred reading medium. Online measures, by contrast, showed shorter mean fixation durations and lower EEG theta band voltage density--known to covary with memory encoding and retrieval--for the older adults when reading from a tablet computer in comparison to the other two devices. Young adults showed comparable fixation durations and theta activity for all three devices. Comprehension accuracy did not differ across the three media for either group. We argue that these results can be explained in terms of the better text discriminability (higher contrast) produced by the backlit display of the tablet computer. Contrast sensitivity decreases with age and degraded contrast conditions lead to longer reading times, thus supporting the conclusion that older readers may benefit particularly from the enhanced contrast of the tablet. Our findings thus indicate that people's subjective evaluation of digital reading media must be dissociated from the cognitive and neural effort expended in online information processing while reading from such devices.

Figure 1. Mean error rates (%) for the comprehension questions in the present study.

Error bars represent the standard error of the mean calculated for the within-participants factor MEDIUM according to the procedure outlined in .

Figure 2. Ratings for the pleasantness of reading (choice of preferred reading medium) in absolute numbers of answers.

Note that two participants were excluded from this analysis: one did not provide an answer, while the other chose two reading devices (tablet computer and book page).

Figure 3. Ratings for the best readability / legibility across the different reading media in absolute numbers of answers.

Note that three participants were excluded from this analysis: one did not provide an answer, while the other two chose two reading devices (tablet computer and book page).

Figure 4. Mean summed fixation durations per page of text (in seconds).

Error bars represent the standard error of the mean calculated for the within-participants factor MEDIUM according to the procedure outlined in .

Figure 5. Mean voltage density measures for the EEG theta band (μV/Hz) per page of text.

Error bars represent the standard error of the mean calculated for the within-participants factor MEDIUM according to the procedure outlined in .

Figure 6. Mean voltage density measures for the EEG theta band (μV/Hz) per page of text as a function of mean summed fixation durations (s) per page.

Regression lines represent the parameters of the minimal adequate mixed effects models for the two groups (see text for details)