Some of you may have read the submission guidelines and rolled your eyes at the deletion of double spaces after punctuation. I decided to explain this further. People get really passionate about double spaces after punctuation. I made the mistake of voicing this pet peeve on Facebook and, after watching people chew each other out in the comments section (it made Hunger Games look tame), I quietly deleted the post and double-checked the locks on my door. Preferences on aesthetics aside, the reason for this schism—and the reason I impose single spacing after punctuation—comes down to the transition between typewriters and computers.
On a typewriter, every character takes up the same amount of space. If this post were pounded out on a typewriter, a capital M would take up the same amount of space as a period. This frequently made it difficult to read due to the out-of-wack spacing, so people would use two spaces after punctuation for clarity. However, when the document would be typeset for publication, the pieces of type used took up different amounts of space: a capital M was much larger than a period, and spacing did not cause problems with readability. So, regardless of what the author of the document typed out, the typesetter would use single spaces instead of double spaces after punctuation.
Enter the age of computers. You may notice on the screen how snug all the letters are, fitting perfectly against each other. The kerning, or space between the letters, is automatically adjusted. The computer essentially does the job of a typesetter by adjusting space, making double spaces after punctuation unnecessary. Frequently, people are still taught to use double spaces after punctuation because that is what their teachers or parents taught—teachers and parents who learned how to type on a typewriter.
Currently, all updated manuals of style require single spacing after punctuation. However, if your professor, boss, or significant other insists on treating a computer like a typewriter and requires double spaces, go ahead and adhere to their guidelines—even if you know they’re wrong!