What I find effective (on both sides of the interview table) is not only asking easier questions, but active encouragement to first talk out and work through the most fundamental, basic aspects of the problem and it's simplest solutions before moving into more advanced stuff.

I think a lot of experienced people's brains lock up in an interview when asked simple questions because they assume that they're expected to skip straight past the "obvious" solution and go straight for some crazy algorithm or explain the fine points of memory/time tradeoff. This often doesn't present as intended - it looks to the interviewer like you don't even know the basics and are grasping at straws trying to sound smart.