recently asked me if I knew of any research that investigated whether or not mixed
case words (WebClient) are easier to recognize than all upper case words (WEBCLIENT).
I wasn t immediately aware of any research on this issue so I turned to the folks
on the PPIG discussion list (sign up at http://www.ppig.org)
and asked if they knew. This resulted in a very interesting discussion from which
the general consensus opinion seemed to be that mixed case is more legible than upper
case. However, nobody was able to point me towards recent studies that clearly demonstrated
this. I was however given some fairly useful references to follow up (for example,
see the bibliography section at the end of www.knosof.co.uk/cbook/sent782.pdf. Following
these up, I came across a paper published in the journal Brain and Cognition that
investigated the effect of case alteration and word length on word recognition (see http://iipdm.haifa.ac.il/case_alternation.pdf ).
Interestingly, they found that mixed case words take longer to recognize than all
upper case words. The effect is especially marked when the words are not recognizably
legal words. Additionally, the difference in recognition time increases when word
may well have some interesting consequences for API design. Should abbreviations be
represented in code in upper case or mixed case? For example, should we use System.Tla
or System.TLA (where TLA is some random three letter abbreviation)? The research might
indicate that we should use TLA but consensus opinion seems to prefer Tla. What
do you think? How about when the abbreviation is well known, such as XML? Should it
be Xml instead?