Good point, Rowan, eye contact is partly a cultural thing.

About the finger-in-the-ear habit: I know one singer who cups her hand behind her ear and sticks her elbow out. This means that she hears her voice beautifully, but anyone sitting to one side may have the sound of her voice and the sight of her mouth masked by the protruding arm. It's hard not to conclude that she's singing more for herself than for the people she's performing to.

Marje