During a job interview, how long does it take for the interviewer to gain a clear picture of the candidate's personality? Recruitment expert Dr Jim Bright said you can make or break a job interview in the first 30 seconds.
Bright has conducted research into recruitment and has found that interviewers can read a person's body language quickly.
"What this shows is that if you've made a positive impression [in the first 30 seconds], the interviewer will tend to spend the rest of the interview looking for confirmation of this positive image," Bright said.
"If you stuff up in the first half-minute, the interviewer will often spend the rest of the time looking for complementary evidence that this person is not right for the position."
An organisational psychologist, Bright has written three books on job hunting and careers, including Jobhunting For Dummies.
While he maintains there are no absolute rights or wrongs in terms of how you conduct yourself in an interview, there are some simple things to be aware of.
Eye contact and posture are the most important forms of non-verbal communication.
Maintaining steady eye contact with the interviewer indicates confidence and trustworthiness.
"Most information about you comes from your face because that's what people are looking at," Bright said. "Eyes are most important, followed by whether you smile or frown."
However, holding someone's gaze for too long can be disconcerting, as can looking from side to side.
"It's OK to look slightly above the interviewer's head, or slightly to the right or left, but with extreme side-to-side looks you can look shifty and uncomfortable, like a cornered animal looking for an escape route.
"Posture is also an important factor," Bright said. Don't slouch in the chair: sit slightly forward. "That conveys you want to try to understand exactly what they're saying.
"If you face a selection panel, make sure to play interview tennis and look from one to the other to the other. If you focus on just one, the others will feel left out."
Be clear and precise. Use simple and direct body language to enhance what you are saying.
So how can you ensure that you make a sterling first impression?
NIDA's head of movement studies Julia Cotton said it was important to be aware of your movements and mannerisms.
"In acting we talk about keeping the body open and receptive," Cotton said. "Body language that closes the body off is doing things like crossing your arms or pulling away from the other person."
Cotton said a common indicator that someone was lacking in confidence was if their body was not balanced and straight, but rocking back and forth.
"One of the exercises I have students do to help them keep their body grounded is to stand with their eyes closed and move their body slowly to feel how their muscles tense, and come back to a position where they feel comfortable," she said.
Gesturing using your arms and hands can add emphasis to a point, but be cautious: if you overdo it you can come across as unsure.
"Some young actors fall into the trap of over-gesturing we call it `windmill arms'," Cotton said. "It can send out the message that you're not sure of what you're saying so you're using your hands as a compensatory message."
Be aware of the handshake. Don't be afraid to initiate it: you will come across as self-assured and a firm handshake can be a potent signal. Cotton said one shake is enough.
It is worthwhile to think of a job interview as being on stage: from the moment you enter the building you are being assessed.
"If you're not a natural talker, you've got to warm up beforehand," Bright said.
"You should start talking from when you wake up in the morning before the interview talk to your parents, your flatmate, to people on the bus. Generally get into the idea of talking, so that when you get into the interview you're not dumbstruck."
Other forms of body language to watch out for include nervous fidgeting and hands on your hips: a stance that indicates defiance.
Holding your hands behind your body is good because it opens you up, but it can also make you seem submissive.
At the end of the day, if you suffer from interview nerves it is helpful to consider that the company is trying to fill a position and you are looking for a job, so remember, you are meeting them on an equal footing.
