Cognition: Human–Computer Communication - Foundations for Designing User-Centered Systems - page 203

Table 7.4 Easier to read text. This is semantically the same text as in Table 7.3 but with most of
the features that cause reading difficulties eliminated, and with the paragraphs indented
Fourscore and seven years ago our fathers brought forth on this continent a new nation, conceived
in liberty and dedicated to the proposition that all men are created equal. Now we are engaged
in a great civil war, testing whether that nation or any nation so conceived and so dedicated
can long endure
We are met on a great battlefield of that war. We have come to dedicate a portion of that field as a
final resting-place for those who here gave their lives that that nation might live. It is
altogether fitting and proper that we should do this. But in a larger sense, we cannot dedicate,
we cannot consecrate, we cannot hallow this ground. The brave men, living and dead who
struggled here have consecrated it far above our poor power to add or detract
The world will little note nor long remember what we say here, but it can never forget what they
did here. It is for us the living rather to be dedicated here to the unfinished work which they
who fought here have thus far so nobly advanced. It is rather for us to be here dedicated to the
great task remaining before us-that from these honored dead we take increased devotion to
that cause for which they gave the last full measure of devotion-that we here highly resolve
that these dead shall not have died in vain, that this nation under God shall have a new birth of
freedom, and that government of the people, by the people, for the people shall not perish
from the earth. —A. Lincoln, 1864
7.3.1 The Effects of Fonts
Reading also interacts with the choice of fonts. Figure 7.2 shows a menu from a
web site (it is the links section on the left hand side of the page, a common design),
where every item is in a different font, and one item even has different colors for
each letter. While there may sometimes be good esthetic reasons for using several
different fonts, that we do not think apply in this case, here it makes it harder to
read the text in the interface. A good rule of is to use no more than three different
fonts. If you are planning to use several different fonts, you should make sure that
you have a very good reason for doing so.
As another example of the significant effect of the use of fonts, Fig. 7.3 shows the
Clearview (also referred to as Clearview Hwy) font ( www.clearviewhwy.com ) .
This font was designed to aid readability and legibility for older drivers and has
been evaluated (Garvey et al. 1998 ). The design addressed each attribute of let-
terforms including stroke width, letter shape, the resulting inside and outside of each
letterform, and the proportional relationship of capital letter to lower case as well as
letter spacing to optimize readability when viewed at a distance. It illustrates how
the readability of fonts can differ. Research at Penn State has shown that the
improved font is 20% easier to read, which means that drivers at 60 mph (miles per
hour) can read the road signs 1-2 s earlier, which gives them more time to make
decisions or to read more of the sign. Another major effect—not shown here—is
that the font also works better at night, when the light used to read signs comes from
reflected headlights, which changes the contrast between the letters and background
(Garvey et al. 1998 ). Note, however, that the font works less well on negative
contrast road signs (dark text on a light background).