Persuasive Advertising - J. Scott Armstrong [180]
High-involvement print ads with paragraphs separated by first-line indents for paragraphs had higher recall than the use of blank lines. Our WAPB analysis found 34 pairs of print ads for high-involvement products, in which one ad used blank-line space between paragraphs while the other used first-line indentations. Recall of ads with first-line indents was 1.14 times better than for ads with blank-line spacing between paragraphs.
9.4.5. Consider justification for moderate to long lines of text
Justification (also called “total justification” or “full justification”) means that the text is flush on both the left and right margins, as this paragraph illustrates. It gives a strong clue as to the end of a paragraph. However, one might argue that the different inter-word spaces might confuse less proficient readers.
Medieval European scribes made great efforts to achieve justification. The advent of the Gutenberg press in 1445 simplified their job. Full justification was used in the first known print ad, which was written by William Caxton around 1480 in an advertisement for a book. Advertisers continue to justify text for long copy, as you can see by examining print ads in nearly any media except the Internet.
Centered text and ragged left are impractical when the objective is to communicate, although they might be useful as part of a distraction strategy.
The evidence on justification shows that the benefits are weak. My suggestion is that when it is easy to do and when it looks good, you might as well do it. For example, it does not look good in books with large fonts such as children’s books. In addition, given the complexities of displays for websites, it makes little sense to try to justify anything other than files that people want to print (e.g., PDF files).
Evidence on the effects of text justification
Justification is slightly better suited to fast readers, judging from on-screen reading experiments. Less proficient readers seem to have difficulties when the spacing between words is uneven (Baker 2005).
Experiments with college students found that comprehension was about 5 percent greater with justified text than ragged right (Hartley and Burnhill 1971). However, other research provides little support for full justification (Jamison 1998).
9.4.6. Squeeze inter-letter spacing gently
Squeezing the inter-letter spacing can help in layout design; for example, it can keep a headline or subtitle on a single line. It particular, it helps to improve appearance when presenting text in columns. Finally, smaller character spacing can reduce media costs by up to 30 percent.
In addition to squeezing inter-letter spacing, consider selecting a condensed font—letters that are normal in form and height, but narrower than the standard. Many typefaces are designed with a condensed form, such as: This is regular Arial type; this is condensed Arial type. Some fonts have ultra-condensed versions.
Do not reduce spacing below 70 percent of normal, although this depends on the fonts that are used. And, when reducing spacing, read the text carefully. Some letters, such as “r” and “n,” might be problematic; for example, in reading “Use this product on burns!” in condensed fonts, some readers might see “burns” as “bums.”
Changes in inter-letter spacing affect readability. This is because people read words rather than letters; in doing so, they seem to depend on the length of a word and on its first and last letters (as well as context, of course). Wider spacing makes it difficult to know where one word ends and another begins.
Evidence on inter-letter spacing
Evidence on this principle is mostly based on received wisdom. However, Wheildon (1995, p. 113) asked 500 subjects to read many print styles. The subjects reported that headlines squeezed between 70 percent and 90 percent were easier to read than normal spacing.
9.4.7. Use phrase spacing for informative text
Spacing can be used to guide readers. The list format, in which