Franchise FC Apparently, (not my research might I add) the brain interprets the top sections of lowercase letters more easily than all uppercase. The study showed that it's possible to cover the bottom half of the words and still be able to read them if they are lowercase, but much less successfully with uppercase.
What I want to know is why anyone would cover half the line on the screen they are reading just to prove this.
As the original idea for developing something easier to read than capitals dates from the Court of Charlemagne, you'd have to be quite old to have been involved in that.
I believe the most comprehensive study to date was done by the Ministry of Transport in the early 60's, and resulted in the "Transport" fonts used on UK road signs.