Yes, FILE is less identifiable than file. All the letters are the same height and have similar shapes with all-caps, whereas lowercase letters have more variety

Yes, FILE is less identifiable than file. All the letters are the same height and have similar shapes with all-caps, whereas lowercase letters have more variety and your brain can recognise the shape of words rather than looking at every single letter. The Wikipedia page for word recognition has some useful links: http://en.wikipedia.org/wiki/Word_recognition http://en.wikipedia.org/wiki/Word_recognition