Getting to know people well is hard—whether you’re choosing a mate, a friend, or an employee for your company. Why? People are strange, complicated creatures who guard their personalities and shift their behavior based on situational cues. But just because picking the right person for your business is a subtle art rather than an exact science doesn't mean there are no scientific principles or research-based insights to guide you.

Science, and psychology in particular, has plenty of ideas to offer on how to hire the best person for your firm. So many, in fact, that the British Psychological Society's Occupational Digest blog was able to kick off 2012 with a round-up of recent findings applicable to entrepreneurs looking to select new talent. Among them are these three insights:

Best practices are useless. Every company is unique in its culture and exact needs, so when scientists compared the hiring decisions of organizations that used so-called "best practices" in the selection process versus those that cobbled together their own procedures, they found no better outcomes among those that hewed closely to experts' recommendations. "This tells us that it isn't about slavishly following a right formula, but evaluating what's been proven to work elsewhere with your understanding of the local context of your organization," summarizes BPS. Or in other words, don't slavishly follow recommendations, including these. Instead, use them for inspiration and ideas.

Tests work. In many industries, studies show you can save yourself the time of quizzing candidates face-to-face about their abilities and just opt for an automated assessment instead. Of course, the tests must be well designed, and this isn't true of every sector, but the results are worth bearing in mind if you’re unsure about testing.

Understand the power of first impressions. You may spend hours or days putting candidates through the ringer of every type of assessment, probing their technical skills and personality under pressure, but psychological research suggests your decision may come down to how the possible hires handled themselves in first few moment after you met more than you’d like to admit. But that’s not always a bad thing according to BPS, which explains that interview scores, "are strongly influenced by the picture gained from the early minutes where rapport is built. Happily, it seems that this isn't simply bias, but reflects some good information picked up—for instance, verbal ability, and some personality factors. Why not recognize this, perhaps by assigning quick ratings after that initial period?"

For more interviewing insights, as well as links to write ups of the individual studies discussed, check out the complete blog post.