When talking with a friend, we usually move our arms, or swing, or make faces that reflect the feelings we have towards what we are saying. However, when we are examining ourselves in an oral that language is not appropriate because it can reflect the insecurity we have and it must be avoided at all costs.
Reflex acts such as moving by putting weight between one foot and another, or touching one's hair, reflects insecurity in what is being said, in addition to also reflecting that one may be lying, or that we are not really satisfied with what we say we say because it is what is in the notes but we do not agree).
Also looking to the left denotes a lie, while to the right would mean telling the truth or agreeing with what we say.
Body language, although it seems silly to us, is something that we must take into account because it can mean a step between passing (because they consider that you have raised the theme to be exposed well and have been eloquent with your actions (body language) or a suspense (due to involuntary gestures but that betray us).