Why is he smiling in this moment — during a question and answer regarding such a serious subject? A smile, when it’s out of context, is always telling.
According to a paper published in the Journal of Personality and Social Psychology, you can come off as more persuasive by speaking slightly louder than you normally do, and by varying the overall volume of your voice (i.e., speaking both more loudly and softly). […] it will make you appear more confident when you speak, which has a positive impact on your overall persuasiveness, according to the study.
