What I learned in teaching police, judges, and attorneys over the years suggested a wisecrack- the criminal justice system must have been designed by someone who wanted to make it impossible to spot lies from demeanor.
The guilty suspect is given many chances to prepare and rehearse their replies before their truthfulness is evaluated by jury or judge, thus increasing their confidence and decreasing their fear of being detected.
Score one against the judge and jury. The direct examination and cross examination take place months, if not years, after the incident, thereby blunting emotions associated with the criminal event.
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