I've found that speaking in front of a camera is a very anxiety inducing experience. Even more anxiety inducing than talking to a person. You become really self conscious of your appearance and every single little move that you make and its hard to ignore the camera when its staring right at your face. Plus in your case you were doing it for an official purpose so there's that pressure too. With the audio recording though, its just something you can toss aside and completely ignore while you have fun talking to the robot. One great way to get over recording anxiety is to treat the recording like its expendable. You're recording it but deleting it immediately so its no biggie. :)