News is better "24/7" than "twenty-four/seven"

People often rely on numeric information to make better decisions. But are numbers always used in a deliberative manner? In preregistered studies, we demonstrated that the presence vs. absence of at least one Arabic integer in A/B tests of headlines increased decisions to click-through from a headline to an article by 3.6% for the Washington Post (7,371 experiments, 19,926 headlines) and 5.2% for Upworthy (22,664 experiments and 105,551 headlines) after controlling for other factors known to increase such engagement. A preregistered within- and between-participant experiment (N=765) further revealed that the presence of at least one Arabic integer (“3”)—relative to verbal labels (“several”) or written-out numbers (“three”)—increased such selections, positive impressions of headlines and their writers, and recall. These findings suggest that people perceive stories associated with Arabic-integer headlines as more valuable and deserving of their limited attention. The effects are inconsistent with Arabic integers attracting more attention and precise numbers providing more information because 1) when precise numbers were written out, they did not have the same effects and 2) using fonts to draw attention to written-out numbers and verbal terms did not increase selections of those headlines over Arabic-integer headlines. Instead, people seem to use a number heuristic—with Arabic integers providing more valued information over other number forms—that superficially guides people’s memory, message perceptions, and engagement with messages. News organizations and other communicators should think more about when and how to harness the power of numbers.