Two Spaces Don’t Make Text More Readable

Great article here, and a super guide to how *not* to do design research:

Ap­par­ently de­fy­ing Bet­teridge’s Law, the study claims to show that two spaces af­ter a pe­riod are eas­ier to read than one. On its face, this also seems to con­tra­dict my long­stand­ing ad­vice to put only one space be­tween sen­tences.

Con­fi­den­tial to two-space re­searchers: you might con­sider mak­ing your pa­per avail­able for free, as it may be the last time that a topic of your re­search over­laps with a wide­spread in­ter­net obsession. Be­cause the study costs $39.95 for a PDF, I’m cer­tain the so­cial-me­dia skep­tics rush­ing to claim vic­tory for two-spac­ing have nei­ther bought it nor read it. But I did both.

True, the re­searchers found that putting two spaces af­ter a pe­riod de­liv­ered a “small” but “sta­tis­ti­cally … de­tectable” im­prove­ment in read­ing speed—about 3%—but cu­ri­ously, only for those read­ers who al­ready type with two spaces. For ha­bit­ual one-spac­ers, there was no ben­e­fit at all.

Incidentally, if you’re not familiar with the whole of Butterick’s Practical Typography, I heartily recommend it to you.