Serif vs Sans Serif

There are plenty of studies that show no difference between the legibility of serif and sans serif typefaces ( Tinker, 1932 ; Zachrisson, 1965 ; Bernard et al., 2001 ; Tullis et al., 1995 ;De Lange et al., 1993 ; Moriarty & Scheiner, 1984 ; Poulton, 1965 ; Coghill, 1980 ).

There are some high profile studies which claim to show the superiority of serif typefaces (Robinson et al., 1983 ; Burt, 1959 ; Weildon, 1995 ) but these have been soundly criticised on points of methodology. ( Lund, 1997, 1998, 1999 ). See this post for a more detailed critique of Weildon’s research.

Particularly interesting is the case of Sir Cyril Burt, well known in psychology circles for being accused of fabricating his results. It turns out that he is likely to have continued this deceptive behaviour in his typographical work ( Hartley & Rooum, 1983 ).

Unfortunately, many researchers, typographers and graphic designers continue to cite Burt and Weildon uncritically, meaning that many of the informal resources on typography found on the web today continues to propagate unsubstantiated claims on the utility of serifs.

Most disappointing however, is that in more than one hundred years of legibility research, researchers have failed to form a concrete body of theoretical knowledge on the part that serifs may play in legibility ( Lund, 1999 ). Nor have they managed to make their work sufficiently known in the typographic community ( Spencer, 1968, p.6 ).

Arguments in favour of serif typefaces

Serifs are used to guide the horizontal “flow” of the eyes; The lack of serifs is said to contribute to a vertical stress in sans serifs, which is supposed to compete with the horizontal flow of reading ( De Lange et al., 1993 )

These are the most common claims when trying to make a case for the utility of serifs. However, serifs cannot in any way be said to “guide the eye”. In 1878 Professor Emile Javal of the University of Paris established that the eyes did not move along a line of text in one smooth sweep but in a series of quick jerks which he called saccadic movements (Spencer, 1968, p. 13 ; Rayner & Pollatsek, 1989, pp. 113-123 ). Unfortunately many graphic designers and typographers continue to use this rationale for the existence of serifs, due to a lack of communication and cooperation with the research community.

Serifs are used to increase spacing between letters and words to aid legibility

Serifs are not required to control letter and word spacing – in fact, serifs would be woefully inadequate for this purpose. In traditional letterpress systems, spacing is achieved with small pieces of metal inserted between the letters, and by the spacing between the letter form and the edge of the print block. Spacing is even easier to manipulate with modern computerised typesetting equipment. ( Sassoon, 1993 ; Rubinstein, 1988 )

Serifs are used to increase contrast (and irregularity) between different letters to improve identification

Well established research has shown that whole words can be recognised just as quickly as letters during an eye fixation and that single letters can be identified quicker when embedded in a word. Such a ‘Word superiority effect’ would indicate that serifs are not needed for distinguishing between single letters ( Reynolds, 1979 ).

Serifs are used to bind characters into cohesive ‘word wholes’

The simple Gestalt created by spaces between words would be enough to bind letters into ‘wholes’. Furthermore, other features such as character ascenders and descenders should have a much greater effect on word recognition than serifs ( Poulton, 1965 ).

Readers prefer body text set in serif typefaces, so they must be more legible

Many studies conducted in the past did indeed find a preference for serif typefaces (Tinker, 1963 ; Zachrisson, 1965 ). However, Tinker commented that perceived legibility was due to a great extent to familiarity with the typeface. 40 years ago sans serif typefaces were not as common as they are now, and if these studies were repeated, it would not be surprising to find completely different results. Indeed, more recent studies have shown that computer users prefer sans serif typefaces for body text online ( Boyarski et al., 1998 ,Bernard et al., 2000-2001 , Tullis et al., 1995 , Reynolds, 1979 ).

What is important to bear in mind is that in almost all legibility studies, reader preference or perceived legibility tends to be inconsistent with user performance ( Lund, 1999 ).

Serifs are used for body text because sans serif causes fatigue

It is often claimed that reading large amounts of body text set in sans serif causes fatigue, but there is no evidence to support this, as measuring fatigue has not been a concern in the vast majority of legibility research comparing serif and sans serif typefaces.

Furthermore, “no satisfactory objective method of measurement has been devised. Subjective assessments of fatigue are subject to modification by a great many factors which may be totally unrelated to the experimental situation”. ( Reynolds 1979, p313 )

Arguments in favour of sans serif typefaces

Serifs are just an historical artefact

This could be true to a great extent, especially since claims attempting to justify serifs in retrospect have been less than convincing.

Many researchers attribute the origin of serifs to the Romans, some claiming that “Roman masons … terminated each stroke in a slab of stone with a serif to correct the uneven appearance made by their tools”. ( Craig, 1980; in Bix, 2002 ). Others state that “design by brush before execution in stone gave rise to … tapering serifs at the terminals of many strokes”. ( Bigelow, 1981; in Rubinstein, 1988, p10 ).

What ever their origin, serifs have been around for so long that perceived legibility is very likely to have been affected by familiarity – readers tend to rate as more legible the typefaces they are most used to ( Tinker, 1963 ; Zachrisson, 1965 ).

Sans serif are better on the web

Although studies of screen reading show no difference between reading from screen and from paper ( Dillon, 1992 ; Bernard, 2001 ), there could be some validity to this argument.

When typefaces are digitised for use on computers, the letter forms have to fit within a relatively small pixel grid, often leading to what are called the “jaggies” ( Rubinstein, 1988 ). Many web professionals such as graphic designers claim that this relatively low resolution cannot render effectively enough the fine finishing strokes of serif typefaces, and that sans serif typefaces lend themselves more naturally to being digitised, and come out cleaner and thus more legible.