Why do some Christains feel the obligation to remove their hats during prayer? As far as I know, Judaism has no tradition of removing a head covering / hat during prayer.  Therefore, the Christian tradition started sometime after the split and it is not an inherited tradition.  Where does this Christian tradition come from?  Is it just a western or US tradition for males?
One of my churches used this passage when requesting all men remove their hats during times of prayer: 

1 Cor. 11:4


  Every man praying or prophesying, having his head covered,
  dishonoureth his head.


In certain cultures, it's possible that the hat is removed and head is bowed as a sign of respect and not necessarily from this verse.