I have seen a thread similar to this some time ago and it was also on a Mac. It was Maya 2008 though as I recall. But the symptoms were the same - no attributes in the channel box / the entire channel box did not appear to be getting redrawn.
As memory serves it turned out to be a graphics card issue and the channel box area was not being redrawn / updated properly.
Unfortunately, I know very little about how Macs work and I am not sure how to check or update graphics drivers and such.
You may want to check your hardware specs and then cross check with the approved hardware list at autodesk.com. There may also be something in the known problems database at the autodesk area forums.
"If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675