How can you not show any emotion?

First, it is important to remember that everything has a biological basis. Therefore a person can be emotionless because if there are no neurotransmitters active in the brain a person will have no sensation of emotion, this is of course often characteristic of a disorder. Also a person may be very good at masking their emotions, which is why women are often perceived as more emotional that men. Even though men experience the same emotional feelings, they do not express them as readily as many women do, this can shed light on the expression of emotion versus the experience of emotion.