University of Tartu Department of Penal Law Professor of Cognitive Psychology and Psychology of Law, two-time Laureate of the Republic of Estonia National Science Prize in Social Sciences, Editor-in-Chief of the international journal Consciousness and Cognition (Elsevier)
The sense of sight is one of the basic tools of successful human activity and well-being. Depending on the task and environmental conditions, visual perception can provide much or even most of our information. This information is carried by images that have become formed or been formatted into symbol-based, readable texts or analog pictures.
There are professions where the processing of visual information is central to the successful and healthy completion of one’s tasks: teachers, researchers, publishers, lawyers. For the latter, this is particularly true of legal professionals who deal with court proceedings, including working with court files. Therefore, we might question somewhat the inclusion of the blindfold as one of Justitia’s symbolic attributes (although we all get the idea very well).
The legibility of a text is the basis for understanding and recollection its premise. This is where the cognitive and mnestic functions of visual perception are manifested. The more effective the visual perception of a text, the more effectual is its comprehension, recollection, memorizing and use of the knowledge through recollection. Reading a text also causes changes in a person’s physiology, which affects his or her health and wellbeing both on the objective level of diagnosis as well as the subjective level of feeling well or satisfied by the activity. This is a manifestation of the occupational health function of visual perception.
These functions need to be understood and taken into account when assessing and predicting the success and healthiness of work activities. And we can also not ignore the ergonomic function: how does the presentation of a text affect the efficacy and comfort of working with it. A person not only looks at a text but also handles it by moving it, repositioning it, spreading it out, making notes in the margins, citing parts of the text, etc.
Throughout the history of civilization, readable texts and images that one might look at and try to understand have mostly been presented on paper: in books, journals, files, etc. But now, text and images are increasingly being presented digitally on computer screens, smart phones and e-readers. What does all this mean in terms of the efficiency and health of processing visual information? This very topical question remains unanswered at the moment. So should we replace paper tools with digital ones or not?
The goal of this text is to provide an overview of scientific research that compares the differences in the psycho-physiological processing of text presented on paper versus screens based on comprehensibility, memorability and the subjective likability and healthiness of text perception.
Differences in the Comprehensibility and Memorability of Text on Paper and Digital Text
This issue is relevant to planning developments in the educational, administrative, media, health care and other systems. Therefore, a considerable amount of research has been devoted to the comparative analysis of the psychological processing of text presented on paper and digital screens. At the forefront is a comparative analysis of cognitive and mnestic functions. Objective and subjective indicators of the effect of textual information processing have been studied.
The objective indicators include, for example, the speed of processing the information presented in a text, the specific factual accuracy of the knowledge gained, the general comprehension of a complex text, the amount and accuracy of reading. Subjective indicators include the likeability of the text medium and knowledge of different data carriers. Some works published in peer-reviewed, international, scientific journals present the results of the authors’ experimental and other empirical research. The rest provides us with the results of meta-analyses based on the observation of a number of other researchers’ empirical studies. What do these articles tell us, what are their conclusions?
Anne Mangen, a researcher at the Norwegian National Centre for Reading Education and Research, and her colleagues studied the level of reading comprehension depending on the text’s presentation using two samples of 15-16 year-old school students (36 vs. 36 participants with equal prior reading skills). A regression analysis of the results showed that reading comprehension was better with paper than with a pdf-format text on a 60 Hz LCD computer monitor. However, the reason for the difference may be the young age of the test group. Therefore, we must look at what such research says about adults.
Israeli researchers Ackerman and Lauterman conducted an experiment with a test group of university students where the average age was 25 (38 reading from screens vs. 38 reading from paper). Both test groups were asked to read a thousand character text and later answer factual and general comprehension questions about it. The time limit was changed within the sample groups: the reading assignment was to be completed within a time limit (7 minutes) or without a short-term limit. A chi-square analysis and dispersion analysis of the results showed higher scores (circa 5.12% higher) and better time efficiency among the paper sample group, especially when reading with a time limit.
The condition for being able to later meaningfully use information is transmission of that information to one’s semantic, meaning-creating memory. A study with 50 participants in England found that although the difference between the speed of learning a foreign text and the accuracy of direct memory was small between paper and electronic media, paper text later showed a significant advantage when it came to comprehensive memory. Other studies have also shown a lower level of comprehension of complicated textbook texts read on a laptop or e-reader versus on paper. However, there are studies that have found no difference in comprehension and memory with electronic and paper texts (especially in the comparison of e-readers and paper text), though some other differences favouring paper have emerged (which I will get into later.)
Meta-analyses that use the results of multiple empirical studies give us valuable, generalized knowledge. One recent analysis is based on two larger studies published from 2000-2017. One was based on studies that used an independent sampling method and the other on studies that compared the effects of two conditions on the same samples. The first analysis, based on the results of 56 studies, showed that reading comprehension with paper texts gave better results in 42 instances whereas electronic texts gave better results in 14 instances. The difference is clear. Using the same sample groups to compare 18 reading conditions, 14 showed preference for paper texts, three for electronic text and one remained “neutral”. The advantages of text on paper were most evident with time-sensitive tasks. Yiren Kong and colleagues ran a meta-analysis of 17 previously published studies. Their regression model also showed that comprehension was higher with text read on paper. They found no difference in speed of reading.
Work based on visual perception contains not just cognitive processing of written text, but may also requires the study and interpretation of graphs and diagrams. Taiwan researchers Lin et al. investigated visual-spatial problem solving capabilities and the effectiveness of visual-spatial short-term memory comparing the paper and pencil method to a touch-screen tablet computer. The results showed that the paper and pencil method gave 10% better memory test results and 20% faster answers. The spatial-visual problem solving was even 35% better than a tablet computer.
From the above, we see that the share of research that shows a comprehensive advantage for information presented on paper is not 100%. These kinds of results have come from perception studies of medical diagnosis texts, assessing the dependence of grades on printed textbooks versus screen versions, assessment of the comprehension of the news media, analyses of e-textbooks, etc.
And yet, the preferences of paper appear in other ways: 90% of medical professionals prefer paper to e-media; books motivate you to be more absorbed in learning than electronic devices; the sensory sensations of printed material are more pleasant; paper is more convenient or pleasant for making notes or adding comments; paper is more handy for navigating between different sections; material acquired equally well on paper may take more time to be acquired using electronic media; for some reason, paper conduces a higher level of focus; although tasks that only take a moment to complete may be equally successful with different types of carriers, the advantages of paper become evident with longer texts (NB! lawyers presumably work more with longer texts); e-tools are inferior in terms of the distribution and spatial marking of sections of a text; moving back and forth throughout the text is more convenient with tabs, bookmarks and fingers and using a bound or stapled book or folder; e-tools give an inferior sense for how far you are from the end of the text; e-tools tend to have a lot of technical defects and compatibility issues.
The results of research by Tuncer and Bahadir is particularly ironic. In their study, 156 university students were taking an introductory course on computers: half used paper texts, the other computer screens. The participants in the study were definitely interested in computers. And yet, they turned out to gain more knowledge from information presented on paper.
Often, work presented as text requires comparative analysis of information and movement between several pieces of information in different directions and repeatedly. Computer monitors and e-readers are less effective for this sort of multitasking than using separate or bound pieces of paper that one can view together, side-by-side, parallelly or during quickly alternating analysis. Understanding and comprehension are supported not only by deciphering the textual information presented as symbols, but also by the spatial design component: specific spatial schemes or layouts are a resource for successful memorizing and problem solving. Paper-pages-tabs-margin notes-markings are a more cognitively effective operational environment compared to consecutively viewed electronic screens.
To summarize the above, we can state that information conveyed on paper is generally more effective in ensuring sufficient comprehension and recollection especially with work that requires concentration.
Subjective Likability and Healthiness of Information Present on Paper versus E-media
The majority of work that compares the impact of different types of information carriers on the accuracy of information processing and the quality of acquisition also measures the attitudes of the participants towards using the different carriers. When it comes to subjective preference and likability, paper predominates. The end of the previous section lists several such preference factors.
It’s clear that the effectiveness of working with texts depends not only on perceptual and comprehension level and efficiency but also on how motivated someone is to work with different texts. Of course, more pleasant information carriers are preferred and generally lead to a larger volume of work (done well). However, we must also remember aspects tied to the health of the workers. Even if some factors of work speed and comprehension are equal between paper and e-tools (and some factors show clear advantages for e-tools, such as text editing and making corrections), a critical comparison must also be made of which method of presenting information is healthier for the perceiver.
In general, the e-tools used to do work can be divided into the following types of information presentation tools: 1) text or image presented on a screen as frames flickering on the phosphor of a computer screen by means of cathode ray tubes (“the traditional computer screen”); 2) frame switching technology that uses LED technology (“modern computer screens” on desktops and laptops); 3) tablet computers; 4) e-readers; 5) the display technology of smart phones.
The characteristics and conditions of use for these visual aids greatly influence the visual perception and the perceiver’s mental and physiological state: the intensity of the emitted or reflected luminous flux, the ratio of emitted light to reflected light, the brightness and colour contrast of the image, the spatial resolution of image details (details such as pixels per degree of view), the image alternation rate (frequency measured in Hertz, Hz; e.g. typical flashing frequencies are 60 Hz, 80 Hz, 100Hz), the spectrum of display colours, light scatter on the screen, the size of the screen and the image (elements) displayed on it, the viewing angle of the screen, distance from the screen, (convenience of) handling the data carrier, etc.
Unfortunately, we must admit that most of these factors show images (text and graphics) presented on paper to be more comfortable and healthier for the perceiver. Among many reasons, we might note that the visual system has evolutionarily adapted to receiving light reflected off of natural sources and practical operations using the help of vision have developed humans’ ability to influence the objects and sings that they see using their hands and bodily positions. Evolution also didn’t shape our visual system to observe nearby images continuously and in a static position (your eye “rests” the best when looking into the distance and during active movement). In that sense, modern technology is unnatural and puts more strain on our senses, the nervous system and our entire organism.
Computer vision syndrome is widespread throughout the world. The main symptoms of this problem are: eye tension and tiredness, headaches, dry eyes, neck or back pain. Factors related to digital displays that can be detrimental to well-being and health include: predominance of emitted light over reflected light, flashing light in many cases, often the image is too high or it is awkward to move or change the position of a desktop or laptop and the impractically small size of the screen on an e-reader or smart phone.
Although technological advances have led to better solutions, they have not been sufficient to eliminate or adequately mitigate many adverse health effects. In addition to traditional computer screens, we now also use tablets and e-readers. We can point out the following when comparing them: an e-reader’s screen won’t irritate the eyes as much as traditional computer screens or tablets; it’s better to read off of those screens because it resembles a regular book and the “e-ink” technology makes the text comparable to printed text; compared to tablets and other computers, a smaller and lighter e-reader is easier and more comfortable to handle (distance, viewing angle).
The downsides are: the screen is too small for many visual tasks; limited functionality and installation capability; light is emitted (not reflected); the image is dim and black and white. Among other problems, a tablet has the following downsides: the screen irritates eyes (flashing, radiation) during prolonged use; it’s more inconvenient to change the viewing angle and slant; weighs more than smart phones and e-readers. But the problems of smart phones are notably bigger because the screen and images on it are very small and they also emit radiation.
Despite advocating e-readers, their use cannot be recommended for most everyday work because their functionality (including communication options, variety and type of material and compatibility) is limited and their use does not mean an end to eye irritation or tension. For example, in a study with 44 participants who read study materials for one hour, those with e-readers experienced more eye strain and irritation. These readers experienced almost five times more disturbingly severe eye strain. Of course, carefully composed comparative studies – like Chu and colleagues – equate all other conditions of reading on paper vs electronic devices, such as the text used, viewing distance, size of image, contrast and luminous flux.
After twenty-minute reading sessions, 30 participants were asked to rate the level of discomfort when reading on paper versus a computer screen. There was a lot more visual discomfort when reading off of a screen: blurred vision, problems focusing the image, eye irritation, dry eyes, eye strain, headache, increased sensitivity to bright light. It must be noted that, compared to LCD-readers, e-ink technology causes significantly less of the above-mentioned vulnerability symptoms. A touch-screen tablet computer causes much more visual fatigue during spatial problem solving than paper.
In conclusion, from the point of view of subjective likability and preference as well as health and well-being, the mental processing of information presented on paper ensures more favourable results, especially as compared to desktops, laptops, tablets and smart phones. In many respects, E-ink technology is more comfortable for the eye than other technologies, but its low functionality, rather limited spatial organization as compared to paper, and limited commenting ability still force a preference for paper.
Additional Commentary and Conclusion
Based on the above, it could be stated that the transmission of visual information (e.g. a written text or graphically presented task) on paper usually ensures better immediate understanding of the information, learning, more effective later use, a subjectively more pleasant experience with better health benefits compared to information displayed on e-technology devices. One can argue against that with the presumption that the inferiority of e-technology comes from extraneous factors such as prior knowledge or attitudes towards different type of media, different levels of experience using them, social myths, etc. Nevertheless, studies that account for such factors show that the advantages of paper persist.
In fact, there are other arguments that speak to presenting information on paper (instead of electronically) other than visual perception and its cognitive processes. A short list includes: 1) electronic media or their storage and transmission is more disruptive and more easily hacked or destroyed than paper information stored on multiple copies; 2) e-technology is more conducive to malicious distortion and counterfeiting (which is harder to detect and less transparent) than files and volumes; 3) in the event of natural, catastrophic or military force majeure, our technological environment and its capabilities may be severely limited or damaged. But legal documents need to be eternal, unsinkable, incombustible and usable even in case of technological disaster. A power outage, hacker activity or pressing the wrong key on a keyboard are only the first buds. The problem in full bloom may be much more unfathomable.
 A. Mangen, B. R. Walgermo, K. Brønnick. Reading Linear Texts on Paper Versus Computer Screen: Effects on Reading Comprehension. – International Journal of Educational Research 2013/58, pp. 61–68.
 R. Ackerman, T. Lauterman, Taking Reading Comprehension Exams on Screen or on Paper? A Metacognitive Analysis of Learning Texts Under Time Pressure. – Computers in Human Behavior 2012/28(5), pp. 1816–1828.
 J. M. Noyes, K. J. Garland, VDT Versus Paper-Based Text: Reply to Mayes, Sims and Koonce. International Journal of Industrial Ergonomics 2003/31(6), pp. 411–423.
 J. Stoop, P. G. Kreutzer, J. Kircz, Reading and Learning from Screens versus Print: a Study in Changing Habits: Part 2–Comparing Different Text Structures on Paper and on Screen. – New Library World 2013/30, pp. 371–383.
 A. Dillon, Reading From Paper versus Screens: A Critical Review of the Empirical Literature. –Ergonomics 1992/35(10), pp. 1297–1326; G. Walsh, Screen and Paper Reading Research – A Literature Review. – Australian Academic & Research Libraries 2016/47(3), pp. 160–173; Y. Kong, Y. S. Seo, L. Zhai, Comparison of Reading Performance on Screen and on Paper: A Meta-Analysis. –Computers & Education 2018/123, pp. 138–149;
P. Delgado, C. Vargas, R. Ackerman, L. Salmerón, Don’t Throw Away Your Printed Books: A Meta-Analysis on the Effects of Reading Media on Reading Comprehension. – Educational Research Review 2018/25, pp. 23–38.
 P. Delgado et al. (cit. 5).
 Y. Kong et al. (cit. 5).
 C. L. Lin, M. J. Wang, Y. Y. Kang, The Evaluation of Visuospatial Performance Between Screen and Paper. – Displays 2015/39, pp. 26–32.
 A. Holzinger, M. Baernthaler, W. Pammer, H. Katz, V. Bjelic-Radisic, M. Ziefle, Investigating Paper vs. Screen in Real-Life Hospital Workflows: Performance Contradicts Perceived Superiority of Paper in the User Experience. – International Journal of Human-Computer Studies 2011/69(9), pp. 563–570; A. J. Rockinson-Szapkiw, J. Courduff, K. Carter, D. Bennett, Electronic Versus Traditional Print Textbooks: A Comparison Study on the Influence of University Students’ Learning. – Computers & Education 2013/63, pp. 259–266; J. Young, A Study of Print and Computer-Based Reading to Measure and Compare Rates of Comprehension and Retention. – New Library World 2014/115(7/8), pp. 376–393; D. B. Daniel, W. D. Woody, E-Textbooks at What Cost? Performance and Use of Electronic v. Print Texts. – Computers & Education 2013/62, pp. 18–23; Y. Sidi, Y. Ophir, R. Ackerman, Generalizing Screen Inferiority-Does the Medium, Screen Versus Paper, Affect Performance Even With Brief Tasks?. – Metacognition and Learning 2016/11(1), pp. 15–33; C. Myrberg, N. Wiberg, Screen vs. Paper: What is the Difference for Reading and Learning?. – Insights 2015/28(2), pp. 49–54.
 M. Tuncer, F. Bahadir, Effect of Screen Reading and Reading from Printed Out Material on Student Success and Permanency in Introduction to Computer Lesson. – Turkish Online Journal of Educational Technology-TOJET 2014/13(3), pp. 41–49.
 See A. Holzinger et al. op. cit., Y. Sidi et al. op. cit., C. Myrberg ja N. Wiberg op. cit., G. Walsh op. cit.; see also D. W. Chen, R. Catrambone, Paper vs. Screen: Effects on Reading Comprehension, Metacognition, and Reader Behavior. – In Proceedings of the Human Factors and Ergonomics Society Annual Meeting 2015 Sep (Vol. 59, No. 1), pp. 332–336, Sage CA: Los Angeles, CA: SAGE Publications; see also Y. Ramalingam, R. S. Naidu, G. Hariish, J. P. Naidoo, Screen Reading vs Paper Reading: An Experimental Study on the Impact of Different Reading Materials on Recall and Comprehension Among Students. – American Journal of Educational Science 2018/4(4), pp. 136–143.
 Z. Yan, L. Hu, H. Chen, F. Lu, Computer Vision Syndrome: A Widely Spreading but Largely Unknown Epidemic Among Computer Users. – Computers in Human Behavior 2008/24(5), pp. 2026–2042.
 Z. Yan et al. (cit. 12); J. R. Anshel, Visual Ergonomics in the Workplace. Aaohn Journal 2007/55(10), pp. 414–420.
 M. M. Maducdoc, A. Haider, A. Nalbandian, J. H. Youm, P. V. Morgan, R. W. Crow, Visual Consequences of Electronic Reader Use: A Pilot Study. International Ophthalmology 2017/37(2), pp. 433–439.
 C. Chu, M. Rosenfield, J. K. Portello, J. A. Benzoni, J. D. Collier, A Comparison of Symptoms After Viewing Text on a Computer Screen and Hardcopy. – Ophthalmic and Physiological Optics 2011/31(1), pp. 29–32.
 S. Benedetto, V. Drai-Zerbib, M. Pedrotti, G. Tissier, T. Baccino, E-readers and Visual Fatigue. PloS one 2013/8(12): e83676.
 C. L. Lin et al. (cit. 8).
 V. Halamish, E. Elbaz, Children’s Reading Comprehension and Metacomprehension on Screen Versus on Paper. – Computers & Education 2020/145: 103737.