WHAT YOU ARE ABOUT TO READ IN THE NEXT PARAGRAPH IS COMMONLY BELIEVED, BUT NOT TRUE — You read by recognizing the shapes of words and groups of words. Words that are in all capital letters all have the same shape: a rectangle of a certain size. This makes words displayed in all uppercase harder to read than upper and lower case (known as “mixed case”). Mixed case words are easier to read because they make unique shapes, as demonstrated by the picture below.
OK, NOW THE TRUE STUFF STARTS — When I started this article the topic was supposed to be why all capital letters are harder to read. Like most people with a usability background or a cognitive psychology background, I can describe the research — just what I wrote in the first paragraph above. I decided to look up and cite the actual research rather than just passing on the general knowledge and belief.
The research doesn’t exist, or “It’s complicated” — Something happened when I went to find the research on the shape of words and how that is related to all capital letters being harder to read. There isn’t research showing that exactly. It’s more complicated, and ultimately, more controversial. In July of 2004 Kevin Larson wrote an article that is posted at the Microsoft website that explains in depth all the research on this topic. I’ve picked out several ideas from that article and am presenting them here. A link to Kevin’s article, plus some of his research citations are at the end of this blog for those of you who want more detail.
It’s parallel letter recognition, not word shape — The old theory on word shapes comes from a psycholinguist named Cattell who came up with that theory in 1886. There was some evidence for it, but more recent research shows that it is letters you are recognizing and anticipating. You don’t recognize words by the shape of the word. You recognize familiar letter sequences. The research strongly suggests that you recognize all the letters in a word at the same time, and then you use the recognition of those letters to recognize the word.
How you read — When you read you have the impression that your eyes are smoothly moving across the page, but that’s not what is happening at all. Your eyes move in quick sharp jumps, with short periods of stillness in between. The quick jumps are called saccades and the fixations are the moments of stillness. Interestingly ,during the saccades you can’t see anything — you are essentially blind. Fortunately these saccades are really fast so you are not blind for long. They are so fast that you don’t even realize you are having them.
How much do you read at a time? — A saccade jumps you about 7-9 letters, but your perceptual span is actually double that. When you are reading your eyes are “looking ahead” using your peripheral vision to see what is coming next. Some interesting eye tracking studies have been done in which the researchers switch out the letters during the saccade. Then they look for the types of errors you make. I won’t go into the detail of this research (references are below if you want to dig more). But the summary is that you read ahead about 15 letters at a time. When you pick up those 15 letters you always pick them up to the right (if you are reading left to right), although now and then your saccade jumps you backwards and you re-read a section of letters.
Here’s the bottom line — That’s probably more than you wanted to know about how you read! Here’s the summary: You read by anticipating the letters that will be in words, and then recognizing those letters. All capital (uppercase) letters are slower for people to read, but only because they aren’t used to them. Mixed case text is only faster to read than uppercase letters because of practice. Most of what you read is mixed case, and so you are used to it. If people practice reading text that is in all capital letters they can get to the point where they are reading that text as fast as they usually read mixed case. This doesn’t mean you should start using uppercase or capital letters for all of your text. People are not used to reading that way, so it will slow them down, and these days it’s perceived as “shouting”. But now you know that uppercase letters are not inherently harder to read. Maybe we can start dislodging that myth?
And, here’s some links and research citations:
Kevin Larson’s article is at: http://www.microsoft.com/typography/ctfonts/wordrecognition.aspx
Adams, M.J. (1979). Models of word recognition. Cognitive Psychology, 11, 133-176.
Bouma, H. (1973). Visual Interference in the Parafoveal Recognition of Initial and Final Letters of Words, Vision Research, 13, 762-782.
Bouwhuis, D. & Bouma, H. (1979). Visual word recognition of three letter words as derived from the recognition of the constituent letters, Perception and Psychophysics, 25, 12-22.
Cattell, J. (1886). The time taken up by cerebral operations. Mind, 11, 277-282, 524-538. Fisher, D.F. (1975). Reading and visual search. Memory and Cognition, 3, 188-196.
Haber, R.N. & Schindler, R.M. (1981). Errors in proofreading: Evidence of syntactic control of letter processing? Journal of Experimental Psychology: Human Perception and Performance, 7, 573-579. Hebb, D.O. (1949). The organization of behavior. New York: Wiley.
McClelland, J.L. & Johnson, J.C. (1977). The role of familiar units in perception of words and nonwords. Perception and Psychophysics, 22, 249-261.
McConkie, G.W. & Rayner, K. (1975). The span of the effective stimulus during a fixation in reading. Perception and Psychophysics, 17, 578-586. Meyer, D.E. &
Paap, K.R., Newsome, S.L., & Noel, R.W. (1984). Word shape’s in poor shape for the race to the lexicon. Journal of Experimental Psychology: Human Perception and Performance, 10, 413-428.
Pollatsek, A. & Rayner, K. (1982). Eye movement control in reading: The role of word boundaries. Journal of Experimental Psychology: Human Perception and Performance, 8, 817-833.
Pollatsek, A., Well, A.D., & Schindler, R.M. (1975). Effects of segmentation and expectancy on matching time for words and nonwords. Journal of Experimental Psychology: Human Perception and Performance, 1, 328-338.
Rayner, K. (1998). Eye movements in reading and information processing: 20 years of research. Psychological Review, 124 (3), 372-422.
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