As a caricature artist, I am constantly trying to improve my understanding of the face. Here is a pencil study I did a while ago.
I focused on the emotion on this piece. I really wanted to get the intensity of the person in this study. I feel the loose pencil work adds to the intensity.
What do you think he is thinking of? Let me know what you think in the comments. Also, if you are working on you ability to draw people from your mind, see my review of an excellent course here.