I was reading a Vim tutorial ( http://www.oualline.com/vim-cook.html#drawing ), and came across this:

This is very useful if you use a 4 space indentation for your C or C++ programs. (Studies at Rice University have shown this to be the best indentation size.)

Is there any truth in these studies?

Note-- i didn't mean for a flame war in indentation -- just whether anyone else has come across tis study before? EDIT: @MaR I made a poll http://poll.fm/3d5kg