Let an FBI spy put you at ease

But it was his work monitoring foreign spies that launched him into his new career as an adviser to businesses on "non-verbal intelligence".

He and his team would follow spies and try to infer from their behaviour what they were up to.

How often did they gather? Which were their favourite restaurants? Were they walking differently one day to the next?

"When we're relaxed, our body has a certain posture," says Navarro. "But when we're concerned about being followed, it changes."

Spies were often taught to glance into shop windows to see if they were being followed. But Navarro could easily tell if someone was doing it to see what was inside the shop or to see who was behind him.

For all but the most diligent spies, he says, the habits and disciplines they learned before being sent into the field yielded quickly to ordinary human instincts.

Once he retired, Navarro was astonished to find how poorly most business people understood the field of non-verbal communication.

It can range from body language to the configuration of furniture in your office.

It boils down to what Navarro calls the comfort/discomfort model.

For all the words people use, how they respond is often the product of a host of non-verbal signals and triggers which make us feel either comfortable or uncomfortable.

However much we might like to think we are motivated by issues of verbal substance, we invest a lot in superficial signals.

If we make others feel comfortable, we are more likely to find work, money and to develop sound relationships. And what comes out of our mouth or appears on a résumé is just a small part of that.

Navarro has some basic, old-school principles for making others feel comfortable. He recommends a tidy personal appearance, conservative dress and good manners.

If everyone at your office wears a suit, wear a suit. Few people succeed as iconoclasts, he writes in his new book Louder Than Words, and the odds are you aren't one of them.

Especially in service businesses, it is vital to do all you can to make your customer feel they can trust you and want to spend their money with you.

He recommends that anyone who provides professional advice — bank managers, lawyers, advertising agents — puts a sofa in their office so clients can feel comfortable.

Always offer them a drink, preferably one you already know they like.

Don't fiddle with a phone or BlackBerry during meetings. Avoid the two-handed handshake, with one hand shaking, the other clamped over the top.

In conversation, stand or sit at an angle to the other person, rather than facing them straight on.

And if your job is to greet people, there are only eight words Navarro feels are acceptable: "Good morning sir/madam. How may I help you?" No "hi there" or "hey" can ever substitute.

It all sounds small-bore, but Navarro says he used to use these techniques to great effect in the FBI when interrogating suspects and potential witnesses.

"In the FBI, the big challenge is to get someone to come and work for you. How do you establish rapport, trust and facilitate communications?"

These are skills, he says, which are not taught at many business, law and medical schools and yet are vital to business people, lawyers and doctors.

To understand the impact of dress on behaviour, one only has to think how differently men carry themselves when dressed in black tie rather than a T-shirt and tracksuit bottoms. But Navarro gives an even more powerful example in his book.

The FBI once ran an experiment in which two groups of agents were given the same hypothetical scenario: a man is holding a woman hostage in a hard-to-reach place, but has access to a phone. How would they rescue the hostage?

One team was dressed in the polo shirts and cargo pants they would wear for SWAT training. The other team wore dark business suits.

The team in suits immediately laid out a plan to establish a perimeter, set up a command post and begin a long process of negotiation by telephone.

The team dressed for training proposed bursting through the door and windows with an assault team and paramedic to bring out the hostage.

"Just by dressing differently, these men had a different mentality," says Navarro. "Their clothes set the attitude, tempo and tone."

Navarro offers a six-step plan to improving one's non-verbal intelligence. It begins with imagining where it is you want to be with your personality and career. The next step is communicating it to yourself and to others.

Then you emulate the best behaviours you can find by reading about and watching people you admire.

Next, evaluate yourself honestly. Is that haircut going to help or hinder you? Do you need a new shirt?

Facilitate the process through reading and practice and finally put it all into action. Do this in a continuous loop, Navarro says, and change will quickly follow.

But isn't this all just a recipe for dreary conformity? Watch the movies from the 1940s, Navarro says, or old images of men arriving in the City of London for work all wearing bowler hats.

They may have looked the same but they still possessed a rich array of personalities.

Once you can understand other people well enough to make them comfortable, then you can be as original as you like.