Leakage cues refer to

Leakage cues are unintended signs that reveal how a person really feels.

They slip out through the body or voice despite an effort to hide the true emotion.

Facial expressions that people misread are errors of interpretation, not these betraying signals.

A characteristic style of facial expression describes a habit, not an involuntary leak of feeling.

A technique used by professional actors is deliberate performance, the opposite of unintended leakage.

Leakage often shows in the feet and hands, which people control less than the face.