Secondary Action.

Secondary action is where a character or more give life to the environment and the world by interacting with themselves, each other or the world to give a more life like feel to the animation. An example of secondary action is shown here in Mass Effect.

From these images, who can see that the NPC hologram who is talking is doing a secondary action whilst talking by moving her hands. This gives a greater sense of realism to the character, despite being a hologram, because she is moving and gesturing needlessly, yet doing so in the way a human would.