This is not a simplistic illustration of the terms introvert / extrovert, but a very complex and subtle reading. These two works were produced at the same time, the same week. Note the watercolour-lead pencil opposition, colour and lack of colour. The framing is very intimate. One person is shown as in an interior. It is not a great hall, it is a small room. There is an intimate bedroom lighting, not the lighting of a room lit by a chandelier. The lighting is condensed. For the other, lighting comes from everywhere. It is open air and in infinite spaces.
In the Introvert, the details are refined, while the Extrovert is prey to powerful touches. In the one, it is a person who takes care of the details, polishing up, while in the other it is an enterprising, dynamic person, who does not dwell on the details.
The Introvert has no real expression on his face. He is lower than you and raises his head slightly. His look tries to match what you want. His mouth expresses many desires, many attempts at seduction. He wants to please, in other words he wants to be adopted. His mouth is open, ready to respond, not to engage in conversation. This face is very ambiguous. This could very well be that of a gay.
In the Extrovert, these lines are observed on a tight, closed jaw. He does not seek to seduce, he imposes. He is not lower, he is slightly higher than you, unlike the Introvert. This is an example of the finesse that is present in interpretation. Finally, these two portraits are an invitation to look at the face as an exercise in morphopsychology.
The background expresses the state of soul of the character. The green at the top shows a coldness at the level of the intellect. In the hair there is some blood red that expresses sanguinary ideas. A black trail is placed at the level of the eyes, and at the level of the mouth a trail of mud which reflects what this mouth can utter as low and vulgar ideas. In other words, each band coincides with feelings.