156 TUGboat, Volume 33 (2012), No. 2 Towards evidence-based typography: First results Boris Veytsman and Leyla Akhmadeeva At the previous T E X Users Group meeting we de- scribed a program to revisit the long-standing dicta of typography from the point of view of experimen- tal science [9]. Indeed, any practitioner of the art “knows” that serif fonts are better for continuous body copy, while sans serif fonts are better for the texts intended to be read in chunks, like advertisements, that optimal line sizes are based on the physiology of eye movement, etc. However, many traditional views about human organisms are not confirmed by rig- orous experiment: after all, a couple hundred years ago people also “knew” that profuse blood letting helps to cure a number of diseases including bubonic plague and the common cold [5]. Thus we started a long term program to study whether the traditional ideas of typography are confirmed by experiment. Recently Legge and Bigelow studied readabil- ity and legibility of text with different font sizes [7] which led them to the so-called ecological hypothesis : the print sizes actually used over the centuries in book making are in the “comfort zone” for a normal vision reader, and variations in the size are of low importance. A natural generalization of this hypoth- esis is that other typographic devices like serifs or their absence do not matter much if they have been used in typography for a long time. We decided to test this generalized hypothesis. In our experiments we asked the subject to read texts typeset differently and answer multiple choice questions about them. T E X allowed us to easily obtain high quality texts with controlled typographic features. In the first series of tests we studied the influence of serifs on reading and comprehension. The exper- iments with serif and sans serif fonts described in the literature [2–4,8] give controversial results: some studies show the advantage of serifs, while some in- dicate sans serif fonts are more legible. One should note that in these experiments (with the notable exception of [8]) the texts were typeset in different “superfamilies” (mostly Times and Helvetica), which may be a confounding factor: there are many dif- ferences between Times and Helvetica besides one being a serif font and another being a sans serif one. Therefore we chose for our experiments a pair of fonts from the same “superfamily”: PT Serif and PT Sans by Paratype [6] (see Figure 1; note the difference in the alphabet width of the fonts due to the serifs). Their shapes are very close, and thus we The quick brown fox jumps over the lazy dog. 01234567890 fi æ œ The quick brown fox jumps over the lazy dog. 01234567890 fi æ œ Figure 1: PT Serif and PT Sans fonts can assume that the presence or absence of serifs is the main difference between the fonts. The experi- ments with Cyrillic readers (n = 238) showed (see Figures 2 and 3) that there was no statistically sig- nificant difference between serif and sans serif fonts — neither in the speed of reading nor in the number of correct answers about the text [1]. 1 These results corroborate the generalized ecological hypothesis. Currently we are studying the influence of the line length (is it really necessary to do two-column typesetting in landscape orientation) and justifica- tion on reading speed and comprehension. Our pre- liminary results indicate that these factors also do not significantly influence the outcome. We are glad to acknowledge the support of TUG and the Federal Program of Russian Federation “Sci- entists and Science Teachers for Innovation in Rus- sia, 2009–2013”. We are grateful to Karl Berry, Charles Bigelow and the participants of TUG 2011 & TUG 2012 for valuable suggestions. Last, but not least, we would like to acknowledge our wonderful students Ilnar Tukhvatulin, Kamilla Mufteeva, Alla Borisova and Aliya Habiryanova. References [1] Leyla Akhmadeeva, Ilnar Tukhvatullin, and Boris Veytsman. Do serifs help in comprehension of printed text? An experiment with Cyrillic readers. Vision Research, 65:21–24, 2012. [2] A. Arditi and J. Cho. Do serifs enhance or diminish text legibility? Invest. Ophthalmol. Vis. Sci., 41(4, Suppl. S):S437, March 2000. [3] A. Arditi and J. Cho. Serifs and font legibility. Vision Res., 45(23):2926–2933, 2005. [4] M. L. Bernard, B. S. Chaparro, M. M. Mills, and C.G. Halcomb. Comparing the effects of text size and format on the readibility of computer-displayed Times New Roman and Arial text. Int. J. Hum.-Comput. Stud., 59(6):823–835, December 2003. [5] Thomas Dover. The Ancient Physician’s Legacy to his Country: Being what he has collected 1 A preprint of the paper is available at http://borisv. lk.net/publications/serif1 Boris Veytsman and Leyla Akhmadeeva