You’ve got the outfit down, studied up on how to sell yourself, and practiced answering questions that could stump you. Your body language in an interview is just as important.

If you’ve heard that 93% of communication is non-verbal, this is why: In 1967, researcher and current Professor Emeritus of Psychology at UCLA Alfred Mehrabian and a group of colleagues that studied body language introduced the 7%-38%-55% Rule. It stands for the impact of words, tone of voice and body language when speaking.

Since then, critics have played the numbers game, claiming these numbers don’t apply to every situation, and that other factors – including the personal history between two people and their roles – also play a part.

However you slice it, one fact remains: when being interviewed by a hiring manager, she is evaluating more than what’s on your resume or coming out of your mouth, says Vanessa Van Edwards, Lead Investigator at Science of People, a human behavior research lab.

“The body language you display when you walk into an interview also creates your first impression,” she says, “and, once people make an impression of you, it is very difficult to get them to change it.”

Your task? Understanding body language do’s and don’ts.

Smiling

Nerves can make some blurt out silly sentences or clam up and stay silent.

They can also have an effect on your smile. Some folks feel they smile too much in an interview, to express confidence and mask nervous feelings, while others try to keep smiling to a minimum to convey an air of seriousness.

Van Edwards suggests smiling when you first meet the interviewer and shake her hand, when you talk about subjects you are passionate about and at the end of the interview when saying goodbye.

“This is especially important for females,” she says. “Smiling too much because you are nervous or trying to build rapport actually does the opposite; it makes females look less smart not more friendly.”

Seating

By positioning yourself across from or beside the hiring manager at a slight angle, instead of facing the person head-on, you avoid looking confrontational and aggressive. Gently rest your forearm on the side of the chair or sofa if that helps you maintain this position.

“Our brains are funny organs,” says Van Edwards. “Research has shown that when we sit directly across from someone we recall less of what was said, we are more negative and feel they are opposing us. Simply sitting at a slight angle can change this automatic brain bias.”

Posture

After seating yourself, your posture comes into play. A droopy position might convey to the interviewer that you are careless and sloppy, while a hunched-over back says “low self-esteem.”

An even spine, with shoulders up and head lifted signifies that you feel comfortable and are confident and relaxed.

“Sit up straight, look at the person to whom [you] are speaking and use gestures which match what [you] are saying,” says Dr. Lillian Glass, author of “The Body Language Advantage.” These might include hand movements that punctuate your statements, while keeping them rested and in view when listening.

Eye Contact

This one is tricky. On the one hand, you want to meet the interviewer’s eyes when you are answering her questions. On the other, you don’t want to put her on edge by maintaining constant eye contact.

Van Edwards suggests using what she calls the “power gaze” throughout the interview.

“This involves looking at people’s eyes and foreheads, and not below their mouths,” she says. “You should aim to hold their eye contact 60-70% of the time.”

One of the easiest ways to get better at body language is to practice in low-pressure situations such as when you are with your friends and family,” says Van Edwards.

“For example,” she says, “if you have a habit of displaying closed-off body language — arms crossed, legs crossed, avoiding eye contact — work on replacing those behaviors with open body language — arms at your sides, standing or sitting straight and facing people directly — so that when  you get to your interview, positive body language already feels natural.”

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