What a great post by Seth Godin - Two Kinds of "Don't Know"
Man-o-man have I seen a lot of the fear based "Don't Know".
Best thing for it - fun. Specifically making the new material into a game. As kids we learn a lot of scary stuff in the form of a game, playground rules still apply. Games put things in perspective, let us sort out the important from the merely urgent. In a game we see lots of different strategies, we try new things, we all fall down, we laugh, and we get back up again.
Sometimes it's the people playing the game that's important, sometimes the game itself. It depends on what is causing the fear. Say you have two teams merging into one team. Say they don't particularly like one another. My suggestion play a game with lots of unexpected communication, like charades, or improv. These desensitize the group and break down stereotypes, we use Pitches & Products for these situations.
If it's new material or new situations that are causing the fear, put the material into the game and let the team play with it until it gets silly.
Remember fun trumps fear.
