Have two improvisers play a scene and a third person watch the scene as if they are a junior psychiatrist. Pause the scene after it has been established and check in with the junior psychiatrist. See what they thought was going on in the scene; obvious facts and names plus any feelings they were picking up on. Their job is not to invent, but to notice. Offer the actors the opportunity to dial up anything they found useful or interesting from the junior psychiatrist as they play out the rest of the scene.