One space between each sentence, they said. Science just proved them wrong.
In the beginning, the rules of the space bar were simple. Two spaces after each period. Every time. Easy.
That made sense in the age of the typewriter. Letters of uniform width looked cramped without extra space after the period. Typists learned not to do it.
But then, at the end of the 20th century, the typewriter gave way to the word processor, and the computer, and modern variable-width fonts. And the world divided.
The researchers then clamped each student's head into place, and used an Eyelink 1000 to record where they looked as they silently read 20 paragraphs. The paragraphs were written in various styles: one-spaced, two-spaced, and strange combinations like two spaces after commas, but only one after periods. And vice versa, too.
And the verdict was: two spaces after the period is better. It makes reading slightly easier.