'Way back in the stone age, when I was a mere highschool puppy, my "Public Speech" class instructor informed us that the "finger in the ear" was a technique used by many radio announcers. We did practical exercises - with lots of discussion, although I never did get to stick my finger in "Tanny's" ear.

Most people are rather astonished at the result the first few times they hear a recording of their own voice played back. Truth is - what you hear "from the inside" is generally quite a lot different than what comes out.

Blocking the feedback from outside with a finger in one ear allows you to hear and control "which voice" you are using.

Most people's conversational speaking voice is rather thin, but with practice one can learn to use a "more resonant" voice. It is easy, however, when using one voicing, to slip back into another. The finger in the ear allows you to assure that you maintian "your radio sound," particularly if you are "projecting" something that is learned rather than run-of-mill-everyday-yellin'-at-the-kids noise.

Some voice teachers will teach the use of the "FIE" to help students learn aspects of voice control. Using mouth shape, vocal chord tension, open or constricted larynx, and emphasising "chest resonance" are all part of learning "taught" singing.

It's also handy if your duet partner is a little off pitch.

John