The entire world has three obvious head movements or gestures of yes no and maybe. The no is a movement of the head from side to side. The yes is a movement up and down while remaining on the same line and maybe which is tilting of the head in different directions. When we take these movements to our survival as hunters and gatherers we can learn from exploration that a no movement is a scan of the area around me without finding something worth stopping for and a yes is an estimation of the worth or validity of a target. The maybe or head tilt usually means either trying to figure the estimation that was not successful in the yes movement or sometimes when the ground is not in your favor such as a heavy brush or low ground.
In the same way we infer up and down movements as decisive such as a sword swing from overhead forward to the target or a straight fist to the head or in less obvious terms walking straight to a person especially from an elevated surface. A person who is trying to avoid contact will move his gaze in a part of a no movement when you look at him or her and the body will turn as well as if he is scanning the savanna as well. Movements of finding out such as head and body tilting are often seen as lack of confidence whether they are or not and are taken as less threatening and decisive.
Use your understanding of the universal human language when dealing with other people to better communicate and calm others by choosing your movement with more awareness and in a fight or better when it is leading to a fight know to read what is happening and act instead of react to what is happening.
People ofter try to intimidate a stronger person into a vulnerability so they can capitalize on it. Keep breathing and relax your eyes and you are half way to self control. From there you will find everything else waiting.