It takes the brain 5x as much effort to speak as it does to listen. What this means is that as the interviewee is speaking, the brain gets distracted and starts jumping around and often ahead, trying to guess what the person is going to say next. When we do that, we forget to truly listen to expert and miss some of the nuances. It is hard to really be present and one has to be very cognizant of the various distractions (looks of the person, accent of speech, surrounding noise etc.) and eliminate them so one can focus.