One space or two? Science weighs in on how to end a sentence

Study aims to settle one of typography's oldest debates
One space or two after a sentence? Science weighs in. (Pixabay)

By Adam Killick

Do you double space when you reach the end of your sentence?

If you think I'm talking about something to do with prison, you're likely under 40. Or possibly over 90.

In other words, you've never used a typewriter. Because if you had, you would probably know that when you typed, you had to hit the spacebar twice after each period. This helped signify, visually, the end of one sentence and the start of a new one.

But then computers came along, and typing became word processing. And most people stopped bothering with the double space, because technology now automatically adjusts spacing to match the width of a particular letter (so an "i" takes up less space than a "w").

The argument used to go that double spacing after a sentence made text easier to read—meaning that your eyes were able to move faster from one phrase to the next.

Whether (or not) to double space was an issue drawn, strangely, along cultural lines, dating back to the 18th century: In Britain, the double space was de rigeur; in France, it was déclassé.

But more recently, it became one of the loudest debates in the admittedly rather quiet world of typography. Tech writer Farhad Manjoo wrote an essay about why double spacing was wrong. Many people flipped out. And many others sided with Farhad. But what does the science say?

In Britain, the double space was de rigeur; in France, it was déclassé.

Well, recently, a study in the journal, Attention, Perception and Psychophysics has put the debate to rest.

So does the double space make reading faster? Yes.

Does that mean we should be using it? No.


The researchers had 60 students wear eye-tracking devices and read several examples of text, some with single spaces and some with double spaces ending sentences.

A computer tracked their eyes, and they found that double-spaced text caused readers to spend fewer milliseconds between sentences.

But there was no difference in overall reading speed or comprehension.

See? Clear as Helvetica.

So the conclusion of the study is that if you are one of the holdouts who continues to prefer double-spacing, then by all means continue — it won't hurt. And if you don't, or never knew what the the fuss was about, then that's fine too.

Whichever suits your type.


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