Overconfidence: how do you protect yourself against it? (book)

Don A. Moore, a professor of psychology at the University of California, has written a book called Perfectly Confident, How to calibrate your decisions wisely. The book is about the question to what extent it is good to have a lot of confidence in your own abilities and performance. Many think that a high level of self-confidence can help to perform well and may be a prerequisite for good performance.

But Moore shows that great self-confidence that is not rooted in reality actually does more harm than good. Overestimation seems to do more harm than good, especially in activities that require effort and competence. But overestimation is also common. How can we protect ourselves from it?

3 Types of overestimation

Moore explains that there are three types of overestimation:
  1. Overestimation: overestimation where your self-assessment is more positive than your objective performance. Overestimation is common. Two mechanisms that play a role in this are wishful thinking (“I want it so it will work”) and planning fallacy (the tendency to underestimate how long it takes to get something done). But self-underestimation is also common and may be related to worry and overestimation of risk.
  2. Overplacement: overestimation where you estimate yourself higher than others. In general, people tend to rate themselves higher than others for relatively simple tasks and known events but lower for relatively difficult and unknown events. Underplacement is also common and can manifest itself in the imposter syndrome (the feeling that you do not really deserve your position and that you may be exposed as a 'fraud' at any time).
  3. Overprecision: overestimation where you overestimate the correctness / reliability of your own judgments or predictions. Overprecision is common, underprecision is rare. Extreme examples of overprecision can be found, for example, with religious fanatics.

The relationship between self confidence and performance

Many, including the father of modern psychology, William James, suspect that there is a causal relationship between self-confidence and achievement. In itself this is not strange. We see many famous and successful people radiate a great deal of self-confidence. But this correlation may not be as strong as we think. Who knows how many confident people there are who have never become successful and therefore remain out of our sight? And who knows how many successful people exist who may have less self-confidence than we think?

And just because self-confidence seems to be linked with success doesn't mean there is a causal relationship. There may be a third variable, such as competence, that causes both confidence and success. In several experiments, Moore and his colleagues examined whether people who were optimistic about how they would perform a task would execute it better than people who were pessimistic about it. Although people generally expected optimists to perform better, the results turned out to provide little or no evidence for this.

The right level of self-confidence

The fact that we often overestimate ourselves does not simply mean that we have to think more negatively about ourselves. Self underestimation is just as much a problem as self overestimation. Where overestimation can lead us to taking too many risks, self underestimation can lead to inactivity and under-utilization of our possibilities. So we must try to find the optimal middle ground. This is the spot where our confidence is an adequate reflection of how good we really are at something.

7 Ways To Protect Yourself From Overconfidence

Our level of self-confidence should be rooted in reality, according to Moore. We can gain more insight into the reality about ourselves and our assessments by applying certain techniques. Here are some examples:
  1. Could I be wrong? When we want to know if an idea we have is correct, we tend to look for evidence to support this idea (this is an aspect of confirmation bias). However, we'd better look for clues that our idea is not correct. By examining where you might be misguided and by examining the opposite of your thinking, you can probably learn more.
  2. Devil's Advocate: By giving people the role of devil's advocate and by inviting criticism, you can get a more realistic picture of what you're doing and discover opportunities for progression.
  3. Estimate probabilities: You can get used to thinking in terms of odds. Instead of trying to determine whether event X or Y will occur, you can teach yourself how to estimate probabilities for both X and Y. This will improve your predictions and decisions.
  4. Objective standards: You can learn to use objective standards when you judge yourself. Rather than asking yourself, how good am I as a bookkeeper, salesperson or whatever your profession is, you can cut these assessments down into bits: how good am I at aspects A, B, C, D and E of my job ? This tends to make people more modest and more realistic.
  5. Wisdom of the crowd: Research has shown that when you need to make estimates or predictions, simply collecting estimates from multiple people and then averaging them can lead to remarkably good estimates, often better than expert estimates. In fact, it seems that you can use the wisdom of the crowd all by yourself. It works like this: first you make your initial estimate and write it down. Then you ask yourself what's wrong with this estimate and why. When you have done that, you make a second estimate. By subsequently averaging these first and second estimates, the quality of your estimate generally increases.
  6. Make which-decisions: Get used to not making whether-decisions, but which-decisions. Instead of asking yourself the question of whether or not I am going to do X (an whether-decision), develop the habit of defining multiple options and then ask yourself what the possible advantages and disadvantages of each option are before deciding.
  7. Post-mortem and pre-mortem analyzes: A post-mortem analysis is an analysis of what went wrong after something went seriously wrong. This can help you gain insight into errors and weaknesses that may prevent errors in the future. A pre-mortem analysis is done during your project (before anything actually went wrong) by imagining that some time has passed and that what you were trying to achieve has gone completely wrong. This can help detect weaknesses and flaws before anything goes wrong. This is a form of defensive pessimism, focusing on what can go wrong in order to avoid it.


Can it be sobering to discover that you are less exceptional, genius, musical, handsome, strong, etc., than you might have thought? Of course. Seeing yourself as amazing or better than others and thinking that you are right and others are not, may be nice here and now. But when these thoughts are not rooted in reality (which they probably aren't) you may regret them later. It can put yourself and others in big trouble. Realism about yourself works better and is therefore worth striving for.