Search on Google for information on how to be less confident, and over 90% of the hits will actually be explaining ways to increase your confidence. This does have its perks. According to research from Washington University overconfident managers are more likely to get promoted. Then, they are also more like to make investment decisions that hurt their companies.
Interestingly, research from the business psychology department at the University College London found that males often compensate for lack of competence by showing more confident behavior. Eventually people are going to catch on to this trend. For those of you that already see the handwriting on the wall, you should study how to become less confident.
The ancient Greeks called overconfidence hubris. Hubris had a connotation of harm to it that is not found in current ideas about overconfidence, which we tend to view as a type of naiveté. But according to laws in ancient Athens, the intent of hubris was to humiliate another to exalt oneself. Hubris was not cured, it was punished. The Greeks had caught onto the idea that overconfidence is harmful. Understanding this is the first step in diminishing it.
Avoid the temptation to blame failure on circumstances, and then turn and around chalk up success to your own ability. Actually realizing the limited amount of control you do have over your environs should put a huge dent in your overconfidence. If you succeed, is not any more likely a result of your own ability than if you fail.
You can begin to determine your actual impact if you are as willing to listen to criticism as you are to praise. Even if you feel the comments are unkind, you may be able to learn something from them. Research from John Hopkins University indicates that for creative people innovative ideas are often spurred on by criticism from others.
Honestly question yourself and be willing to listen to others who do the same. This is not being negative but rather avoiding the “confirm bias.” Confirm bias is another way of saying that people are will listen to facts that back up what they currently believe and ignore facts that are counter indications. Both should be given equal weight.
Finally, let go of the illusion that the perception of success is more important than actually performing well. Perceptions are based on what others say about you. However, this may not reflect what they actually think. I recall a colleague who always responded to the manager’s requests with an assurance of what excellent work he could expect. But it became evident after a while that actually getting these request done in an excellent manner was not a priority. The colleague actually admitted to me that his enthusiasm was just play acting. But I didn’t have to tell the manager this, he already knew it. Beware, when people know you are faking it, they have less compunction about treating you poorly.
When any leader climbs beyond their ability on claims that they cannot fulfill, people are not as likely to give them a second chance. People become increasingly disgruntled because they feel their trust has been violated. Just as praise was higher for the confident leader, the fall is father. And hitting the ground hurts.
Artwork: Detail from Icarus by Joos de Momper
 Goel AM, Thakor AV. Overconfidence, CEO selection, and corporate governance. J Finance. 2008; 63: 2737–2784. doi: 10.1111/j.1540-6261.2008.01412.x
 Chamorro-Premuzic, T. “Confidence: Overcoming Low Self-Esteem, Insecurity, and Doubt,”
 Johns Hopkins University news release, August 21, 2012, Don’t Get Mad, Get Creative: Social Rejection Can Fuel Imagination, JHU Carey Researcher Finds
 Russo, JE. Schoemaker, PJH. and Russo, EJ. Decision traps: Ten barriers to brilliant decision-making and how to overcome them, 1990