**Non-Verbal Back-Channels**: - Nodding: When someone nods their head while you speak, it's a non-verbal back-channel that indicates they are actively listening and agree or understand what you're saying. - Eye contact: Maintaining eye contact with the speaker is a non-verbal way of showing interest and engagement in the conversation. - Smiling: A smile can be a non-verbal back-channel that conveys approval, agreement, or appreciation for what's being discussed.