One Space or Two? That Recent Study Won’t Tell You.

A recently released study tested whether it was better to put one space or two spaces after a period. A commenter at Kieran Healy’s Twitter feed comments:

I guess this confusion isn’t surprising, but the “rule” has never changed. It’s always been two spaces for monospaced fonts, like the ones on typewriters, and one space for proportional fonts, like the one you’re reading now. There was good reason for this:

  • Monospaced fonts like this one already have a lot of air.  Two spaces make it easier to quickly distinguish when a new sentence begins.
  • Proportional fonts like this one are denser and don’t have that problem. Spaces and capital letters jump out at you.

More to the point, proportional text in magazines, books, and newspapers is usually justified on both right and left—like this paragraph. When text is justified, typesetting equipment ignores your spaces entirely, putting in just enough to make the line lengths come out right. So it doesn’t really matter what you do.

Still, what about the study? As it turns out, the authors tested only monospaced fonts, which is odd since almost no one uses them anymore. Here’s an excerpted and colorized version of their main result:

Among people who preferred one space, reading speed was about 5 wpm higher with one space. Among people who preferred two spaces, reading speed was about 9 wpm higher with two spaces. In other words, people preferred whatever they preferred, and the difference wasn’t very much anyway.

Oddly, though, the folks who preferred two spaces were generally faster readers than those who preferred one space. For $39 I suppose I could find out if the authors had anything to say about this. However, I suspect it means that the difference between the two groups isn’t random.

So the whole study is pretty useless.  What would be more interesting would be a study of proportional fonts.  Over the past couple of decades, it’s become far more common to use a ragged right margin, like the one you’re reading now.  The reason is readability: By keeping the spacing constant, instead of tweaking it to make the line lengths come out evenly, the text is easier to read.  But with even spacing, would two spaces after a period make the text even easier to read?  I don’t know!  Someone should do a study to find out.

Thank you!

We didn't know what to expect when we told you we needed to raise $400,000 before our fiscal year closed on June 30, and we're thrilled to report that our incredible community of readers contributed some $415,000 to help us keep charging as hard as we can during this crazy year.

You just sent an incredible message: that quality journalism doesn't have to answer to advertisers, billionaires, or hedge funds; that newsrooms can eke out an existence thanks primarily to the generosity of its readers. That's so powerful. Especially during what's been called a "media extinction event" when those looking to make a profit from the news pull back, the Mother Jones community steps in.

The months and years ahead won't be easy. Far from it. But there's no one we'd rather face the big challenges with than you, our committed and passionate readers, and our team of fearless reporters who show up every day.

Thank you!

We didn't know what to expect when we told you we needed to raise $400,000 before our fiscal year closed on June 30, and we're thrilled to report that our incredible community of readers contributed some $415,000 to help us keep charging as hard as we can during this crazy year.

You just sent an incredible message: that quality journalism doesn't have to answer to advertisers, billionaires, or hedge funds; that newsrooms can eke out an existence thanks primarily to the generosity of its readers. That's so powerful. Especially during what's been called a "media extinction event" when those looking to make a profit from the news pull back, the Mother Jones community steps in.

The months and years ahead won't be easy. Far from it. But there's no one we'd rather face the big challenges with than you, our committed and passionate readers, and our team of fearless reporters who show up every day.

We Recommend

Latest

Sign up for our newsletters

Subscribe and we'll send Mother Jones straight to your inbox.

Get our award-winning magazine

Save big on a full year of investigations, ideas, and insights.

Subscribe

Support our journalism

Help Mother Jones' reporters dig deep with a tax-deductible donation.

Donate

We have a new comment system! We are now using Coral, from Vox Media, for comments on all new articles. We'd love your feedback.