Bill Kanasky, Jr., Ph.D. talks about the importance of effective listening skills by the witness during testimony. Listening is a skill that must be taught by a neurocognitive expert because the brain is not wired naturally to listen, particularly to the degree required during questioning. Bill dispels the myth that witnesses should engage in active listening during their testimony. Active listening is a communication tactic whereby the listener is analyzing the gestures, body language, tone of voice, posture, etc. of the speaker to understand their point and then when responding, adjusting the listener's own body language, tone, gestures, etc. to acknowledge you understood what the speaker was saying. The skill of active listening is not meant for an adversarial situation like a deposition or trial. 
When preparing a witness for testimony, you want your witness to practice passive, focused listening and not spending energy on trying to interpret opposing counsel's body language, tone, and posture as these can be a trap for your witness. In an adversarial environment like testimony, active listening will actually hurt the witness as the opposing counsel is often trying to manipulate the witness. The purpose of active listening is to send non-verbal signals to the speaker to acknowledge that you are hearing and understanding what they are saying. This is not relevant or appropriate during testimony.