It can be easier to tell if someone’s lying when you can’t see their face. In a US, UK, or Canadian court of law, witnesses aren’t allowed to wear a hijab or niqab because of the long-held belief that seeing someone’s face helps you detect lies- but new studies show lie-detection accuracy was actually higher when witnesses were veiled because observers focused on verbal clues of deception. When witnesses had no veils, observers were more prone to being distracted by misleading visual clues, and their results were no better than guessing. Source