We evolved to understand the noises of others. We evolved to understand that a certain feeling leads to a certain noise emanation and or a certain facial expression. We then learn that we can manipulate ourselves in such a way as to fake those emanations or expressions and therefore manipulate the situation in our favour. When someone makes a joke we don't find funny, we fake a laugh in order to manipulate them into thinking we are good company and that we get along. It shows them we present no threat. physically or emotionally. This is an example of our survival instinct, this is an example of Moneky Mind.
