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Revisiting ALL UPPERCASE LETTERS vs. Upper And Lower Case

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I’m sometimes surprised by which of my blog posts people get passionate about. Take, for example, my post on whether all uppercase letters are inherently harder to read than upper and lower case. I wrote the post back in 2009, yet someone posted a comment on it today, 8 years later. And last week someone said the post was “utter BS”.

Since the all uppercase topic seems to still be hotly debated, I thought I’d write a quick update. It appears there was a research study done in 2007 that I missed when I first wrote the post. The research confirms, as I said 8 years ago, that:

  • All uppercase letters are not inherently harder to read.
  • All uppercase letters don’t slow down reading speed.
  • In fact, in this study, done with both normal vision and low vision readers, people with low vision performed BETTER with all uppercase letters, presumably because they were larger.
  • This better performance effect with all uppercase disappeared when they increased the size of the font so that it was large even in upper and lower case.
  • All uppercase letters did not slow down the normal vision people.

It’s a small sample size, but it was statistically significant, and so far as I know there is still no research showing the opposite, so, I’m sticking to the idea for now, that all uppercase letters are not inherently harder to read.

HERE’S THE RESEARCH REFERENCE:

Aries Arditi and Jianna Cho;. Letter case and text legibility in normal and low vision. Vision Res. 2007 Sep; 47(19): 2499–2505. Published online 2007 Aug 6. doi:  10.1016/j.visres.2007.06.010

Comments

5 responses to “Revisiting ALL UPPERCASE LETTERS vs. Upper And Lower Case”

  1. Scott Barnard Avatar

    I think it’s important to acknowledge that even if there is no reduction in readability, there is definitely a perception that all caps is undesirable in certain circumstances to a significant number of people (like in comment sections :-). As a result, a reader may simply choose not to read something that is in all caps. Thus, it does become a usability issue if you want a user to read something and they happen to be one of those people who dislikes all caps and thinks it is harder to read.

  2. Nick Avatar

    Also, USING ALL CAPS is pretty much the written equivalent of yelling to a lot of people. Probably because it’s commonly used to emphasize things.

    Which, of course, is more of a unofficial –but commonly agreed upon– etiquette rather than a actual fact. But some people are REALLY passionate about this. (It’s actually funny because, besides that, there really is no true relation between it and yelling.)

    I guess there could be some sort of nocebo effect in people with a bias against all caps, no?

  3. Jacque Fryday Avatar
    Jacque Fryday

    ALL CAPS can cause confusion in some industries where use of acronyms is prevalent, such as Software Development and Telecommunications, especially in the Video sector where channel names, package names, site names, and acronyms are used in development and change management:
    – Which words are names?
    – Which words are acronyms?
    They can be harder to distinguish.

  4. Joe Price Avatar
    Joe Price

    Hello Susan,

    I’ve enjoyed reading your books over the years. Your articles on the use of ALL CAPS are really interesting. It seams that when you say “harder to read” you’re referring to the criteria of speed. What other criteria do you think is important to consider? I’ve been thinking about discomfort (like what we experience with the color vibration phenomenon) and comprehension. Are you familiar with any research that touches on those subjects and perceived difficulty to read.

    1. Susan Weinschenk Avatar
      Susan Weinschenk

      All the research I’ve found focuses on all caps and reading speed.

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