Do mask-wearing witnesses deprive criminal defendants of their right of confrontation? Does impairing the ability of jurors and lawyers to fully assess “demeanor” result in less reliable verdicts? Can voir dire be fair if prospective jurors’ faces are covered? Must we require use of transparent face masks? Or is this all a Shakespearean “much ado about nothing” because we— the great majority of lawyers and judges—can’t detect deception with any degree of reliability and often no better than chance?

To answer this we first need to distinguish between demeanor as a general “early warning system,” a tool for discerning that a particular question has hit the witness or prospective juror emotionally and thus warrants some follow-up; and the more discrete claim that facial gestures and responses can reveal deception. Rarely does that distinction come through in the law; and rarer still are the lawyers who grasp the difference.