Are self-confident people more successful? Or do successful people become more self-confident?

In this chicken-or-the-egg argument, one thing is certain: every study conducted in the past 50 years on self-confidence and success has proven that the two are at least related. That is, self-confident people are more successful in all areas of life. And successful people have a high level of self-confidence.

Mark Leary is a noted researcher on the subjects of self-confidence and self-esteem. He is a professor of psychology at Wake Forest University in Winston-Salem, North Carolina.

An important part of self-confidence is what psychologists call a sense of self-efficacy, says Leary. That is the belief that you are able to accomplish a particular goal: "I can make my relationships work" or "I can do this job."

A person with self-efficacy is more likely to try new things. She will tend to rebound better after failure. And she is more persistent in the face of obstacles.

This creates the connection between self-confidence and success as it is documented in the scientific literature and as it shows up in everyday situations.

Albert Bandura is a psychologist at Stanford University. He is also a leading researcher in the field of self-confidence and self-esteem.

In a paper on self-efficacy, Bandura writes: "Perceived self-efficacy is defined as people's beliefs about their capabilities to produce designated levels of performance. Self-efficacy beliefs determine how people feel, think, motivate themselves and behave."

A strong sense of efficacy enhances human accomplishment and personal well-being in many ways.

People with lots of confidence in their capabilities approach difficult tasks as challenges to be mastered rather than as threats to be avoided. They set themselves challenging goals and maintain a strong commitment to them.

In the face of failure, confident people can also heighten and sustain their efforts. They quickly recover their sense of efficacy after failures or setbacks. They attribute failure to insufficient effort or a lack of knowledge and skills that are attainable.

Confident people approach threatening situations with assurances that they can exercise control. Such a productive outlook produces personal accomplishments, reduces stress and lowers the risk of depression.

In contrast, people who doubt their capabilities shy away from difficult tasks that they view as personal threats. They have low aspirations and weak commitment to the goals they choose to pursue.

When faced with difficult tasks, they dwell on their personal deficiencies, the obstacles they will encounter, and all kinds of adverse outcomes rather than concentrate on how to perform successfully. They give up quickly in the face of difficulties.

People lacking confidence are slow to recover their sense of efficacy after a failure or setback. When they fail, they think it's because they lack abilities, and they lose faith in themselves. They fall easy victim to stress and depression.

Another important part of self-confidence is self-esteem, a term with which many people are familiar.

Your sense of self-esteem stems from your actual emotional feelings about yourself. It is tied specifically to your views about the degree to which you see yourself as acceptable to other people and the degree to which you believe you are loved by those around you.

A sense of self-esteem lets you believe you are an acceptable person, that you are likeable and will have friends. It frees you from having to worry about whether your behavior is likely to result in rejection.

Studies link self-esteem and self-confidence to success. But does success raise self-esteem and self-confidence or do self-esteem and self-confidence create success?

According to Leary, the only way to test the link is to artificially induce low self-esteem and low self-confidence in a group of people who are high in these attributes and see whether it changes the level of success in their lives.

It is for this reason that the connection has not been proven: conducting such a study would be highly unethical.

We know that high self-esteem and a strong sense of confidence are related to good mental health, higher educational achievement, literacy, lower dropout rates, better physical health, better economic standing -- just about all the good things you could think of.

It would seem, then, that if you suffer from low self-esteem or self-confidence, you would want to take steps to develop these characteristics in yourself.

A confident person looks relaxed, calm and poised. Self-confident people tend to stand taller with their head up. They engage in more direct eye contact.

Leary notes that this is true for our primate cousins, as well. Researchers have found that the chimps and gorillas with the power--the strongest ones--convey this in their body language.

Obviously self-confidence is an important ingredient for success. But if it's lacking, it is possible to fake it. Putting on a false front will allow a person to get through a variety of sweaty-palm inducing situations.

Getting through scary or difficult situations by mimicking self-confidence has the added benefit of widening your "comfort zone." That's important to people lacking in self-confidence or self-esteem.

Over time, the more uncomfortable or scary situations you force your way through by faking it a little, the less you will need to fake it. Each time, your self-esteem and self-confidence are naturally raised a notch or two.

Leary says the only drawback to faking self-confidence is, for instance, when you embellish your qualifications for a job and end up being hired for something you simply cannot do.

You may end up feeling like a fake, having been hired under false pretences. And the stress that results from the fear of being "found out" can be extreme.

Conversely, it is possible to be too self-confident. A person who is overconfident can end up being non-productive -- that is, persisting when they really should be giving up.

Audrey Brodt is a psychologist in Denver. She does some consulting in the business world in addition to her clinical work. She agrees with Leary that it is possible to fake it, if you are calm, cordial and a good listener.

"A giveaway for people who want to look confident but they aren't is that they talk too much," Brodt says.

Her best advice is to set realistic expectations for yourself, and to accept that you have a lot to learn. Instead of trying to get people to like you, help them to feel comfortable with you. Forgive yourself for making mistakes and find out what you can learn from them.

"People who feel stable and secure with themselves are more willing to tell people that they did a good job. They work better in a team."

"To be a good leader, you had better have a pretty good sense of who you are," says Brodt. "And if you have that sense, you have confidence."

Brodt says she has worked in some situations in the business world where a leader lacked confidence, and it created problems.

One of the things we do to discourage ourselves is to compare ourselves to other people, says Brodt.

"There will always be people smarter, there will always be people richer, there will always be people more competent. The issue is self-improvement, and that will come if you apply yourself and persevere."