The July article in Harvard Business Review presents an interesting study on the value of "Connect first and then Lead." The author Amy Cuddy and her colleagues, discuss the attribute of warmth and strength in communicating trust and then credibility with your colleagues or employees. I see that Recruiters are always on the look out for warmth - genuine, down to earth discussion of who they are and what they are passionate about. If candidates are cool, aloof and hard to read, we often sign them off to a holding place for maybe future opportunities. If they have not done their homework and preparation to discuss their purpose, successes and lessons learned, we miss the real person.
Think about how you communicate warmth over the phone for most first interviews are really screening discussions before getting to meet the client or hiring manager. Is your voice lower in tone, eliciting calm, confident and concerned about addressing the interviewers needs. Or, is the candidate high pitched, fast talking and you almost want to say, "slow down, could you repeat that." I have had those calls and actually ask for them to slow down.
I think if we lead with competence, which is wonderful, then we don't get to see the real person and what they are all about from the human perspective. So, lead with warmth and competence. They are both important, however, connect with your listener or partner first and see what happens. You will learn a whole lot more about the situation and make it to the next meeting with the hiring manager.