When you are interviewing a candidate for a job, the most important factor to consider maybe something you may have never even thought about: nonverbal communication.

When people communicate, they are constantly sending out information, using body language, such as posture and gestures, as well as their tone of voice and facial expressions. These signals are often perceived on a subconscious level, and they form the basis of first impressions.

Recent findings of micro-expressions indicate that people pick up on fleeting facial expressions, lasting only a fraction of a second. Slowed down video recordings showed that people tend to mimic each other’s micro-expressions, indicating a level of understanding occurring too quickly for individuals to be rationally aware of.

Some studies have found that nonverbal communication accounts for more than two-thirds of our impressions. And, as described in Malcolm Gladwell’s book Blink, our split-second judgments based on these impressions are usually very accurate. Becoming more aware of the nonverbal signals you are receiving, as well as those you may be sending, can be a big help when it comes to interviewing job candidates.

While there’s no hard and fast definition of what each expression or gesture means, increasing your awareness can give you a big advantage in an interview situation, and can also help you see what your own biases may be so that you don’t fall prey to them.

How can you use nonverbal communication to your advantage when interviewing?

Feelings and attitudes can be conveyed with posture, whether a candidate is feeling straight up for the job or the weight of the world is on their shoulders. An open, relaxed posture has a positive impact, and a closed posture, with arms crossed and shoulders hunched, carries a negative impact. Leaning forward indicates interest, and leaning back means the opposite.

Pay attention to the candidate’s eye contact. Is their gaze direct and at ease, or do they glance furtively at you, around the room, or at the floor? Maintaining eye contact longer indicates more self-confidence.

Look for discrepancies between what the candidate is saying and any nonverbal cues. If a candidate answers no while nodding her head up and down, pay closer attention. And if the candidate jiggles his foot while answering a pretty straightforward question, beware.

If you notice something like this, the best approach is to ask a lot of questions. If someone is not being entirely truthful, it will be harder to maintain a lie under more detailed questioning. Of course, some of these nonverbal cues can be due to nervousness, so be careful about jumping to conclusions.

You can increase your powers of nonverbal comprehension. Make a practice of observing people, in any situation. Try to guess what’s going on between the people at a table near you at a restaurant. At social events, pay attention to the body language and expressions of the people you talk to. You can experiment with your own body language and tone of voice, and observe the reactions.

All of this means that you should pay attention to your intuition about a candidate. Trust that you are picking up more information than you may be consciously aware of, and pay attention to your hunches. Then, use that information, in balance with the objective findings you have gathered about their work experience, job references, and assessment results, to make your decision.