The Scientific Case for Two Spaces After a Period

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From The Atlantic:

This is a time of much division. Families and communities are splintered by polarizing narratives. Outrage surrounds geopolitical discourse—so much so that anxiety often becomes a sort of white noise, making it increasingly difficult to trigger intense, acute anger. The effect can be desensitizing, like driving 60 miles per hour and losing hold of the reality that a minor error could result in instant death.

One thing that apparently still has the power to infuriate people, though, is how many spaces should be used after a period at the end of an English sentence.

The war is alive again of late because a study that came out this month from Skidmore College. The study is, somehow, the first to look specifically at this question. It is titled: “Are Two Spaces Better Than One? The Effect of Spacing Following Periods and Commas During Reading.”

It appears in the current issue of the journal Attention, Perception, and Psychophysics. As best I can tell, psychophysics is a word; the Rochester Institute of Technology defines it as the “study of the relationship between stimuli (specified in physical terms) and the sensations and perceptions evoked by these stimuli.” The researchers are also real. Rebecca Johnson, an associate professor in Skidmore’s department of psychology, led the team. Her expertise is in the cognitive processes underlying reading. As Johnson told me, “Our data suggest that all readers benefit from having two spaces after periods.”

“Increased spacing has been shown to help facilitate processing in a number of other reading studies,” Johnson explained to me by email, using two spaces after each period. “Removing the spaces between words altogether drastically hurts our ability to read fluently, and increasing the amount of space between words helps us process the text.”

In the Skidmore study, among people who write with two spaces after periods—“two-spacers”—there was an increase in reading speed of 3 percent when reading text with two spaces following periods, as compared to one. This is, Johnson points out, an average of nine additional words per minute above their performance “under the one-space conditions.”

Link to the rest at The Atlantic

PG has been typing for so long and so automatically, he wasn’t certain how many spaces he uses after a period.

When PG learned to type (Yes, on a typewriter. His mother made him take a typing course in high school. Most useful class he’s ever taken.), the standard form was to use two spaces after each sentence.

In monospaced fonts like the long departed Courier, two spaces made for a more noticeable break than the proportionally-spaced fonts that became the standard when personal computers took over.

This is a monospaced font with two spaces after the period.  This is 
a monospaced font with two spaces after the period.  This is a 
monospaced font with two spaces after the period.  This is a 
monospaced font with two spaces after the period.  

This is a monospaced font with one space after the period. This is 
a monospaced font with one space after the period. This is a monospaced 
font with one space after the period. This is a monospaced font with one 
space after the period. This is a monospaced font with one space after 
the period.

In the ancient days of typewriters, there were a few IBM models that produced proportional text, but correcting errors was a huge problem. With a monospaced font typewriter, each character and its associated blank space before and after the character was the same width, so an i  was the same width as an m. With proportional spacing, if an i was typed instead of an m, there wasn’t room to white-out the i and insert the m with Liquid Paper without intruding on the character following the m.

Monospaced ii and mm

Proportionally spaced ii and mm

Expertly correcting a single mis-typed character in a monospaced font could be done without making the correction too obvious (see Correcting Selectric for the height of that art). Depending upon the formal or informal standards of a particular business, the acceptable number of corrections that could be made without retyping the entire page varied. To whom a letter was being sent or for whom a document was being created also impacted how many corrections were permissible.

Law offices were generally the most particular. It was not unusual for a will to require perfect typing with no corrections. A typo on the last line of a page in a will required retyping the entire page.

In large offices, typically only those secretaries who could almost always type a page with no errors were likely to have IBM Executive typewriters with proportional spacing. Secretaries (almost always female) did all the typing because non-secretaries (almost always male) didn’t know how to type. PG caused mild consternation when he requested a typewriter for his personal use at work during those long-gone days.

PG can’t remember when he changed from two spaces to a single space after the end of a sentence, but he’s pretty certain his automatic default today is one space.

35 thoughts on “The Scientific Case for Two Spaces After a Period”

  1. I turned in my very first submission to a publisher with the (requisite in my day) two spaces between sentences. The editor sent it back for me to take the second space out because two spaces was not “house style.” Software notwithstanding, the publisher wanted (and my current pub also wants) copy they will not have to mess with. Or mess with as little as possible. Therefore our subs are supposed to be print-ready at the time we send in the unedited file. Can’t blame them for wanting to save money. Now I’m hard-wired for one space between sentences unless I suffer a brain fart.

    • My non-fiction publisher insists that I submit mss using a Word template that they supply. I like it that what I see is very close to what my readers will see, although I admit that when I am using slower devices, I type into a dirt simple template, then copy and paste into the publisher’s complex template. Double spaces are automatically normalized to a single space in the template.

      For me, the important thing is to leave page design to the page designer. Sometime, I might put on a page design hat, but when I do, I will (reluctantly) take off my author hat.

  2. I too, in writing my books, use two (2) spaces after the period. I found, in reading my first book, it was difficult to tell where the end of the sentence was. It was emphasized more acutely in try to read a book on a phone; as in e-books. So, I changed my style and found it, as mentioned above, easier editing. And much easier reading.

  3. This whole discussion is akin to scholastic debates over the number of angels that could dance on the head of a pin.

    Spacing after periods is an issue for a page designer, not authors, and is only tenuously connected to how many times the author hits the space bar. In the days of typesetting, the linear distance between the period and the start of the next sentence was determined by the typesetter, not the number of spaces in the manuscript.

    It only makes sense to worry about the number of spaces after a period when the physical output of the typewriter was delivered to the reader, but not today when the output of a word processor is a a markup language, which leaves the physical distance between the period and the next sentence to the style guide of the display tool.

    Sheeesh. This is the 21st century, not 1921.

    • lol – Yes. That was my reaction as well. The window of opportunity for this debate ended long ago. I, personally, would find ebooks easier to read if there were a blank line between paragraphs instead of a piddly first-line indent, but there are some battles not worth fighting. 🙂

      • I recently revised my standard Kindlegen style sheet to add space between paragraphs. That is the better way to do it – a blank line expands with the font size, which can put way too much space between them.

        Kindlegen is rather strange, too – Amazon style says first-line indent for paragraphs, but that is not what is generated unless you specifically put it in your style sheet file. (I hope they do not change this, by the way; what is in the style sheet should be the way it comes out.)

        • lol – my very first ebook, I put a blank line after each paragraph, deliberately. I thought it made the story easier to read on a Kindle.

          I was called on it by one of the readers who reviewed the book. What I didn’t realise was that the extra lines jerked the reader /out/ of the story each time, because it was unexpected. -sigh-

  4. I type two spaces automatically, and I’m sticking with it. It’s invisible in web browsers and some ebooks (depending on the formatting) and visible in print.

    The argument always is “computers are smart and they can increase spacing between periods, so two spaces are unnecessary.” And I’m like, “okay, great, but computers aren’t programmed to do that, so double spaces are important, and if computers were programmed to do that, they could just as easily remove double spaces while they were at it.”

    So modern typography can do whatever it likes, and I’ll take note, but until actual, practical display conventions change, you can pry my two spaces out of my cold, dead hands.

    • Given what the OCR did/does to some books (Thomas Sowell’s _The Vision of the Anointed_ e-book [arrrgh]) when it misreads commas as periods, I shudder to think what would happen to readability with two spaces after those periods.

      I’ve seen worse OCR scan conversions, but wow, the publisher fouled up so badly by not having someone at least glance at the file before publishing the e-book.

  5. I had two spaces drilled into me by old-school English and typing teachers, therefore it just doesn’t look right to me without the second space and it takes me out of the moment. So, for that reason, in my case, yes, single spacing does slow me down when reading.

    More importantly, as the world has progressed to using the fuzzy font as I get older, I have trouble spotting something as small as a period. That is, I need all the help available in recognizing the end of a sentence.

  6. If you write for publication, ALWAYS use two spaces. Some magazines and publishers want one space which can be done with a universal find and replace to remove the extra space. If they want two, and you’ve only put one, you have to insert them yourself. I did this once with a 100,000 word novel, and it wasn’t fun.

    Open space whether with more space after periods or shorter paragraphs is a good thing if you are writing anything but academic papers. It makes the reading more appealing. Large blocks of text even turn me off.

    • If you write for publication, you should be sure to read the guidelines before your submit anything. They really do mean it even if you think the rules are ridiculous (like two spaces after a sentence).

    • Another option would be to do a Find and Replace. Find period-space and Replace with period-space-space. Works in Word and in Scrivener. Did this in reverse often enough when I used to format manuscripts for clients.

        • Replace quote-space with quote-space-space. Unless you put spaces after your opening quote…

          Had an interesting read the other night about ellipses. Great debate on the site I was on (sorry, I didn’t bother bookmarking it, most of the discussion was rather idiotic).

  7. For once, I didn’t follow up the OP; the head was already on the desk…

    Even without the flaw of testing under conditions that are nothing like reality, the “finding” that people who insert two spaces read faster with two spaces is the equivalent of saying that people who read faster with two spaces insert two spaces. Classic example of cherry picking! (Or tail-chasing, if you prefer.)

    Three percent is likely of statistical insignificance, too, unless they have a truly huge sample. Very unlikely.

  8. Of course a lot of what we read today is in HTML where the extra space will be discarded and in books printed – or displayed – in proportionate fonts where the extra space is also ignored; so the study is really only relevant to reading typewritten text, something I rarely come across.

    The full Atlantic article gives some reasons to regard the results with a skeptical eye and reading the “Eye-tracking study” section of the original paper shows that the reading being studied was nothing like any reading one would do outside a laboratory (the text was presented on an old CRT display, in 14 point Courier New with quadruple spaced lines).

    • And with justified text a line can be full of spaces between words that a wider than a standard space, making it less likely that the extra space after a period will provide the claimed benefit.

      • True, and I especially noticed it on my Kindles before Amazon updated the software to allow hyphenation.

      • That was the bane of my existence during my days as a typesetter. You had to change the spacing in the line without making it too noticeable or the editor (I worked on magazines) would send it back complaining about the spacing. Thankfully, Atex allowed you to play with the vb strings (variable band spacing between the letters).

        It’s easier with Adobe InDesign but still a pain in the butt when designing my print books. I use the discretionary hyphen if at all possible.

  9. Oh, for goodness sakes. It’s obvious what to do. If two spaces make reading the sentence better, then three would make it better still. HA!

    (Of course, once translated to the web page, all those hard fought spaces vanish. HA!)

    • In my older books, there’s often three spaces after a period. It DOES make it easier to read. I’ve had this argument with teachers many times. It’s far easier to proofread with two spaces after a period, for instance. So I’ll be using two spaces when the rest of you moderns have quite typing entirely.

        • That was automatic, and it isn’t as readable AS FAST as two or three (three is definitely faster). Try it on a page of manuscript, you’ll see. This was DEFINITELY the way it was done in earlier years (the example I showed to my teacher was a book typeset in the 1930s). However this turns out, I typed it with two spaces after the periods. So, now, I’m going through it and making it three-we’ll see what the software does with THAT.

      • It’s far easier to proofread with two spaces after a period, for instance.

        That’s the key, for proofreading.

        Any trick to help the process. To catch the typos. I change things up all the time.

        – Changing font, font size, stripping everything back to pure text, no formatting, etc…, each time I see the prose in a different way. It’s all too easy to run your eyes over the same string of text again and again, and completely miss what’s right there.

        My flaw is writing “the the” without realizing it, and never seeing it until I change the page up.

          • For what it’s worth, you could always feed you text to Word as the spell checker (not the grammar checker) reports duplicate words as an error – at least it does in Word 2007 which I’m still using. Of course, you’ll still have to page through looking for items underlined in red and, unless you have a custom dictionary for proper names, there might be a lot of underlining.

            • The dictionary for Word leaves much to be desired even before creating a custom dictionary that includes Catmage names like Zahavin and Hakham (as well as the word “Catmage”).

              That said, I go through the options and uncheck the most annoying parts of the Word grammar checker and let it catch me duplicating words. It’s worth it.

            • That was a feature in Word 2000 as well (yeah, still using it as it doesn’t know about the internet so doesn’t keep trying to phone the mothership.)

  10. Something for when a correction was a lot of work.

    Not sure if it’s useful today – other than to add to one’s page count … 😉

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