A promising job candidate comes in for an interview. She's got a stellar resume, spot-on experience, and seems like a pleasant sort. What's the natural reaction of most business owners? Turn on the charm and try to convince this talented prospect of the merits of your company while you also evaluate her for skills and cultural fit.

Fat chance of that working out, says a new study.

The team behind the research dug into the dual nature of interviewing (you're often both selling the job and probing the candidate) by setting up fictional interviews with study participants. Half the "interviewers" were asked to prioritize selling the job, while the other half focused on digging into the candidate's qualifications. Both groups then evaluated the candidate using a standard measure that has been shown to predict job performance. Which group got a better sense of their interviewee?

Don't Go With Your Gut

Fans of instinctual hiring decisions, take note: Apparently, when it comes to interviewing, effort pays off. Those interviewers who put more effort into evaluating their candidates did a better job of it than those who were consciously selling the role and thus had less time and focus to devote to examining the candidate in depth. Left to rely more heavily on their gut instincts, this second group did a poorer job of getting a handle on their interviewee.

"If you want to find the right match, you are better coming up with a series of diagnostic questions," study co-author Dan Cable, a professor of organizational behavior at London Business School, told the Financial Times.

The research team followed up this initial study with another one using real-world interviews and came to the same conclusion. Splitting your brain between appealing to a candidate and judging him or her simply doesn't work. "The more interviewers adopt a selling orientation, the less able they are to make judgments that accurately predict applicants' future success as newcomers," wrote the study authors.

Though in a quirk of psychology, the research team also found that while the more rigorous evaluators outperformed the fly-by-the-seat-of-their-pants participants, those told to be more dutiful were actually less sure of their conclusions. It's yet another example of the axiom that confidence is a really lousy predictor of competence.

Be Quiet!

The takeaway here for those interviewing, on one level, is quite simple--just be quiet! All that jabbering on about the merits of your organization is almost certainly getting in the way of your ability to get a handle on the candidate in front of you. This raises another question, though. Companies can't simply skip selling the role to choosy candidates entirely, so when should this essential wooing of potential employees take place?

The researchers don't offer specific guidance, but they stress that whatever you do, don't try to do both at the same time. "This could be done either by having evaluation and selling conducted by different people, or at different stages of the hiring process," they suggest.

Do you try to sell candidates in the interview room?