Sunday, March 11, 2012

Screen vs. Paper, some information and thoughts

I had assumed the 'retina' (eye can't detect individual pixels at the normal usage distance) display on the latest ipad was really about more impressive graphics, i.e. for games and video playback, but was very interested to see the comment that such displays would make a difference to simple reading.

It seems that the low quality of electronic displays has been postulated to result in significantly slower reading speeds with respect to paper, and the idea is that such vastly improved screens will overcome this. The article linked above says that reading is about half as fast on a standard resolution kindle versus paper, but also that there has not been a lot of recent research on the topic, and one of the most important references is a paper from as far back as 2001 (which suggested 10-30% speed differences).

This is a fascinating area which I think is of increasing importance as screen input becomes more and more the default mechanism, not just for offices, but for schools, colleges and even hobby reading at home.

The 'google scholar' service is an excellent resource for the layman (like myself) to search for related papers, for example those on screen and paper reading differences . What follows are the results from a brief investigation of the topic; however this is something I must return to again, and deal with in more detail.

What the studies say 
One (more) recent (2008) paper  ("Computer- vs. paper-based tasks: Are they equivalent?" provides a nice overview of the state of the literature at that time. According to this paper, pre-1991 many studies indeed resulted in some indication that paper reading was better in terms of reading speed, accuracy and comprehension, but there were also in all areas studies which found no significant differences. One major issue with these old studies is the display technology involved at the time, which for a fact resulted in more tiredness for the eyes, which obviously would have been an influencing factor. Similary the level of competence and experience of subjects in those days, when computer use was much less prevalent, is also something which needs to be considered. In my own view, changes in technology and usage question to some extent, but not completely, the relevance of these old studies.

Of the 10 studies listed :

  • 5 found reading slower on screen as compared to paper, 3 found no differences
  • 2 found comprehension worse when using a screen, 4 found no differences


The paper goes on to say though that since 1992 studies have been more aware of the need to preserve equivalence between the screen and paper versions of the testing task, and thus less reliance on partial performance indicators such as reading speed. However although now considered of less interest, differences in reading speed have been suggested even in studies using modern technology.

Modern studies pay more attention to other areas. For example there is the theory that using a computer involves more 'cognitive load' than reading from paper, with one study reporting "Although they found no significant difference in the comprehension scores or the overall workload scores for the two media, significantly more workload was reported on the effort dimension for the computer-based task. This finding is interesting, since it suggests that individuals need to put more effort into the computer task:"

Of the 20 post-1992 studies listed, if considered in light of a general 'which is better screen or paper' (speed, comprehnsion, accuracy etc.) half reported no difference, while 4 suggested benefits to the electronic method, and the same number , 4, suggested the opposite, that paper was more advantageous.

Beyond the effect on the individuals behaviour in pursuit of their own private or professional goals, one very important issue mentioned in this paper is the equivalence of paper based tests versus an electronic version. Given the amount of such electronic testing that is now performed, in all kinds of areas, and while many studies have found no differences, some have, and this means equivalence probably cannot always be simply assumed, but needs to be established. The paper concludes " total equivalence
is not possible to achieve, although developments in computer technology, more
sophisticated comparative measures and more positive user attitudes have resulted in a
continuing move towards achieving this goal."


Overall it seems the evidence is inconclusive, with a slight balance in favour of paper versus screen in certain simple areas, such as speed. However, balanced against this are many advantages of electronic formats, for example ease of retrieval and search mechanisms. So while the reading of one particular document might be better done from hard copy, the overall exploration of a volume of information is greatly facillitated by it being in electronic format.


More than just reading
Another important point I think is that studies cannot just focus on limited screen vs. paper tasks performed in isolation, but must consider as well our overall behaviour when it comes to the different media. This is raised in this interesting blog post  which references the point that 'materiality matters' made by an Anne Mangen, who agured in a journal article : "The reading experience includes manual activities and haptic perceptions (what the skin and muscles and joints register), and so as activities and perceptions of that kind are changed from one kind of reading experience to another because of the object, the reading experience, too, will change."

The point, which I consider a very valid one, is that reading on a screen means more than just considering it as electronic paper; the screen is part of a particular world in which we have certain general behaviours.

For example, I personally think that reading documents online is at risk of being contaminated by other online reading habits we have, habits which are adapted to dealing with a torrent of often un/semi-interesting or relevant information. We are so used to scanning webpages, search results, chain emails that I think we have developed mechanisms to skip through them, our hands contsantly on the mouse, scrolling incessantly. This approach is so different to the way we handle paper information, devoting our mind and body completely to it, with relatively little opportunity for distraction, and even physically reading in a different way - moving our eyes across it, and only turning the page occasionally, as opposed to our eyes staying fixed while we scroll the text past them.  Of course we can skim hard copies as well, but I think the brute physical stability of it results in a difference to how we handle webpages, and electronic documents. The point is not that electronic reading is necessarily of lower quality than of hard copy, but that we need to handle different types of information in different ways, and bad habits from one area might infect another. We use computers for many things, and so performing a task with them in reality is going to involve the general habits, attitudes and dispositions we have in dealing with electronic media, and this is something which might not be considered when testing individual tasks in isolation in a laboratory. If someone is used to skimming a newspaper every morning online, then this might affect how they read an important document later in the day when sitting at the same computer in the same environment. In contrast, reading a document as part of a study would be to do so in a completely different psychological setting, and might well be done differently.

Relevant to this is the result in the 'Computer- vs. paper-based tasks' paper above that people reported a higher workload for performing a task on a computer than on paper. Simply the fact of using a computer for the test had a psychological effect on the subjects, and this has to do with how we use computers in general, and not the particular task being tested. Hence only if such background behavioural information is also studied and understood, can it be effectively compensated for in any particular task test.

Beyond the medium being the message, the medium shapes us, and hence pinpointing the differences between media, is never going to be a simple task.




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