"The Man" represents the opposite of the Beast to the Kindred (regardless of gender). It is the reasoning, planning, social part that remains after the Embrace has installed the Beast in a vampire's soul. It is not necessarily any more human, but maintaining a balance between Beast and Man is an important part of maintaining one's Humanity.
Social interaction is important to reinforcing the Man, and at the same time vampires who are losing touch with the Man find social action more difficult. When the Man has been lost permanently, the vampire becomes a draugr.