A perspective from the political world: When I arrived as a junior staffer on Capitol Hill, I noticed the lower you were on the totem pole, the more you walked with your head held up. The more seniority you gained, the more you walked with your head down, to avoid talking to other people. Chiefs of Staff would walk quickly, looking at the floor. Interns and Staff Assistants walked proudly with their heads held high.
I also found this trick worked very well if I wanted to go places I wasn't supposed to be. Just pull out my blackberry, pretend to be engrossed in something important, powerwalk, and I could go just about anywhere unchallenged.