It's an age-old conundrum: How do you promote yourself to managers or prospective employers without sounding too impressed with yourself? The answer, says Jeffrey Pfeffer of the Stanford Graduate School of Business, is to get a recruiter to do the promotion for you.

Having someone else sing your praises can take the edge off negotiations where money, position and status are at stake, says Pfeffer, a professor of organizational behavior. For one thing, you're seen as a more pleasant person than someone who's pushing their own virtues. For another, you're more likely to get a better salary or contract, he believes.

While research has been conducted on the negative effects agents and recruiters might have, their "positive interpersonal effect" hasn't been thoroughly examined. To determine how such intermediaries can help lessen the negative consequences of self-promotion, Pfeffer and several colleagues conducted studies to measure the reaction of decision-makers (specifically, hiring managers and book editors) to job candidates and prospective authors. In each case, the candidate fared better when they had a third-party champion.

The reason? "An agent or recruiter can say things that you could never say about yourself, and can shield you from interpersonal frictions," Pfeffer says.