The dispute about sans serif versus serif fonts: An interaction between the variables of serif and stroke contrast

Aim: It is a long-lasting dispute whether serif or sans serif fonts are more legible. However, different fonts vary on
numerous visual parameters, not just serifs. We investigated whether a difference in word identification can be
attributed to the presence or absence of serifs or to the contrast of the letter stroke.
Method: Participants performed a word-recognition two-interval, forced-choice task (Exp. 1) and a classic lexical
decision task (Exp. 2). In both experiments the word stimuli were set with four new fonts, which were developed
to isolate the stylistic features of serif and letter-stroke contrast. Two measures (i.e., font-size threshold &
sensitivity) were analysed.
Results: The threshold measure of both experiments yielded a single significant main effect of stroke contrast such
that low stroke contrast elicited lower than high stroke contrast. The sensitivity measure of Experiment 1 yielded
a single significant effect of the interaction between serifs and stroke contrast. Specifically, at the sans-serif level,
low stroke contrast revealed better sensitivity, relative to high stroke contrast. At the serif level, the opposite
stroke contrast pattern was observed.
Conclusion: Sans serif fonts with low stroke contrast yield better performance and if a serif font is used, high
stroke contrast yields better performance than low stroke contrast. Limitations and future directions are
discussed.