Why Microsoft Word Now Considers Two Spaces After a Period an Error

One of the greatest debates in typographical history is arguably an empty one. It centers on the idea of nothingness—specifically, the number of spaces found between the end of one sentence and the beginning of another.

And what a difference a single keystroke can make. Virtual wars have been waged over that humble second space. Some maintain that two spaces between sentences make paragraphs easier to read; others, like Slate’s Farhad Manjoo, who wrote in 2011 that “typing two spaces after a period is totally, completely, utterly, and inarguably wrong,” vehemently disagree.

Now, a veritable powerhouse has entered the fray—and definitively taken a side. As Tom Warren reports for the Verge, Microsoft Word has started marking double spaces between sentences as errors. Though the feature isn’t yet universal, the company has begun trialing the change in desktop versions of the program and will likely be rolling it out to all users soon.

Before panic ensues among “two-spacers,” take comfort in the fact that the program’s suggestion is just that—a suggestion. Microsoft Word is an exceedingly passive editor and can be rejiggered to ignore all sorts of spelling and grammar quirks it might otherwise flag. Users will be able to accept the change, ignore it once or disable the program’s ability to highlight two-space gaps entirely.

“As the crux of the great spacing debate, we know this is a stylistic choice that may not be the preference for all writers, which is why we continue to test with users and enable these suggestions to be easily accepted, ignored, or flat out dismissed in Editor,” says Kirk Gregersen, partner director of program management at Microsoft, in a statement to the Verge.

Still, the truth of the matter is that double-spacers are a rapidly disappearing demographic. As Avi Selk reported for the Washington Post in 2018, many proponents of the rule are traditionalists from the era of manual typewriters, which relied on monospaced type, with each character occupying an equal amount of horizontal space.

To help readers more easily spot the ends of sentences, the two-space rule was put into effect—and for many, the habit stuck, even as typewriters gave way to computers that offered more proportionally spaced fonts, writes Ellen Gutoskey for Mental Floss. (Courier fonts are a notorious exception.)

Nowadays, style guides that recommend double spacing between sentences are few and far between, according to Slate. Some even argue that two spacers are no longer enhancing readability, but diminishing it.

“A space signals a pause,” David Jury, author of About Face: Reviving The Rules of Typography, told Slate in 2011. “If you get a really big pause—a big hole—in the middle of a line, the reader pauses. And you don’t want people to pause all the time. You want the text to flow.”

In 2018, however, a scientific study appeared to gently clap back at this notion. As James Hamblin reported for the Atlantic at the time, researchers from Skidmore College found that two-spacers—those who already write with two spaces after periods—read 3 percent faster when a second space appears after a period.

That difference is a very small one. And the finding didn’t apply to natural one-spacers, who read at essentially the same speed in both circumstances. On the whole, the study was also imperfectly designed, according to the Atlantic. Its 60 participants were all college students, and the font used in the tests was monospaced Courier New.

Ultimately, the findings may simply be a reflection of the flexibility of the human mind, said Rebecca Johnson, one of the study’s authors.

“It’s not like people COULDN’T understand the text when only one space was used after the periods,” she told the Atlantic. “We can comprehend written material regardless of whether it is narrowly or widely spaced.”

Still, even if the difference is primarily stylistic rather than utilitarian, people have gotten up in arms for far less. Microsoft Word’s new development, then, will likely continue to stoke that fire.

Writing for the Atlantic, Hamblin has already clearly picked a side, stating, “I plan to teach my kids never to reply to messages from people who put two spaces after a period.”

Katherine J. Wu | | READ MORE

Katherine J. Wu is a Boston-based science journalist and Story Collider senior producer whose work has appeared in National Geographic, Undark magazine, Popular Science and more. She holds a Ph.D. in Microbiology and Immunobiology from Harvard University, and was Smithsonian magazine's 2018 AAAS Mass Media Fellow.