"Once we have made a choice or taken a stand, we will encounter personal and interpersonal pressures to behave consistently with that commitment. Those pressures will cause us to respond in ways that justify our earlier decision." Robert Cialdini

"One of the most difficult intellectual confessions is to admit you are wrong.  Behaviourally we know we are subject to confirmation bias.  Eagerly we wrap our minds around anything and everything than concurs with our statement.  Too often, we misjudge stubbornness for conviction.  We are willing to risk the appearance of being wrong long before a willingness to personally confess our own errors." Robert Hagstrom

"The average trader doesn't want to hear a painful truth.  They want something in accordance with what they hope for.  When they buy a stock they believe all the news, rumours, views and lies that are bullish, but just let some report come out that is bad or let someone tell him something unfavourable about the stock he has bought and he refuses to believe it.  It is the truth that will help him and truth that he should want to hear, not something that will build up his hopes and causes him losses later." William D Gann

"In my judgement, all great traders are seekers of truth." Michael Steinhardt

“It is the peculiar and perpetual error of the human intellect to be more moved and excited by affirmatives than by negatives; whereas it ought properly to hold itself indifferently disposed towards both alike.” Francis Bacon

"We rarely seek out evidence that undercuts our first explanation, and when that evidence is shoved under our noses we become motivated skeptics - finding reasons, however tenuous, to belittle it or throw it out entirely." Philip Tetlock

"Charlie and I believe that when you find information that contradicts your existing beliefs, you've got a special obligation to look at it - and quickly." Warren Buffett

"We constantly need to be open to new information that may cause us to alter previous opinions or decisions." Ed Wachenheim

"You know, Darwin used to say that any time he got any evidence that flew in the face of his previous convictions, he had to write it down in the first 30 minutes or the mind was such that it would reject contrary evidence to cherished beliefs." Warren Buffett

"We strive to eliminate biases in our decision making that could cause us to reject new information or cling to erroneous beliefs." Seth Klarman

“What the human being is best at doing is interpreting all new information so that prior conclusions remain intact.” Warren Buffett

“Of course, if you make a public disclosure of your conclusion, you're pounding it into your own head.” Charlie Munger

“When one shares an investment thesis publicly, it can be more difficult to change one’s mind because the human mind has a tendency to ignore data that are inconsistent with a firmly held view, and particularly so, when that view is aired publically.” Bill Ackman

"I never liked talking to my limited partners about ideas I had, because you become somewhat wedded to it, it's harder to change your mind over time, you become pre-committed to your positions and so forth. That's always been my stance" Todd Combs

"If you speak up and put it [investment idea] on record, you end up getting too wedded to your thesis and that's dangerous because everything you’re invested in is a function of the facts and circumstances on a given day, it changes." Ted Weschler

“The more public you become with your positions the harder it is for your ego to let go of a position. You can’t let your ego slow you down when the facts change. Don’t talk openly about your positions until you are strong enough to change your mind in front of the crowd.” Ian Cassel

“When you write things down, they typically become public, they are available for other people to see. So you want to be consistent in yourself but you also want to be consistent in the eyes of the people whose regard you care about.” Robert Cialdini

“When you pound out an idea as a good idea, you’re pounding it in.” Charlie Munger

"Over the years, I began to realize that it was a bad idea to speak publically about stocks I own.  The issue isn't that other investors might steal my best ideas.  The real problem is it messes with my head.  Once we've made a public statement, it's psychologically difficult to back away from what we've said - even if we come to regret that opinion." Guy Spier

“People tend to accumulate large mental holdings of fixed conclusions and attitudes that are not often re-examined or changed, even though there is plenty of good evidence that they are wrong.” Charlie Munger

“Insidious for investors are the following biases .. ‘Anchoring effect’ constitute a class of robust psychological phenomena showing that people adjust insufficiently for the implication of incoming information. We form beliefs around an anchor, and additional incoming data must fight against the inertia of the anchor, even when it is objectively irrelevant to the judgement at hand.” Frank Martin

“The consistency bias or commitment bias that comes from talking in a public group that Charlie Munger talks about where, If I stand up on stage and I praise a wonderful traits of Horsehead or Fiat, and later things don’t go the way I expect them to go, can be pretty powerful.” Mohnish Pabrai

"I believe it is important for investors to avoid seeking out information that reinforces their original analysis.  Instead, investors must be prepared and willing to change their analysis and minds when presented with new developments that adversely alter the fundamentals of an industry or company.  Good investors should have open minds and be flexible." Ed Wachenheim

“Failure to handle psychological denial is a common way for people to go broke. You've made an enormous commitment to something. You've poured effort and money in. And the more you put in, the more that the whole consistency principle makes you think, ‘Now it has to work. If I put in just a little more, then it 'all work’. People go broke that way, because they can't stop, rethink, and say, "I can afford to write this one off and live to fight again. I don't have to pursue this thing as an obsession in a way that will break me." Charlie Munger

"All of us want to read new information and have it confirm our cherished beliefs. I mean, it is just built into the human system. And that can be very expensive in the investment and business world." Warren Buffett

Commitment is a very strong psychological problem that most humans have. Once you publically commit to a certain position and then later facts show otherwise to be able to own up to it and be honest to alter yourself. The only defence I’ve tried to use on that front is to try to be honest.” Mohnish Pabrai

"Simple inertia stops people from acting on blindingly clear signals that they should buy or sell.  There may be huge downside risks on stocks they own.  Reading a newspaper account of bad news at a company is much more likely to dissuade an investor from buying its stock than to cause someone who already owns the stock to dump it." Leon Levy

"People become overconfident because they never bother to document their past track record of wrong predictions, and then they make things worse by falling victim to the dreaded confirmation bias - they only look for evidence that confirms their preconceived hypothesis.  The only protection against overconfidence is to systematically collect data, especially data that can prove you wrong." Richard Thaler

"Another indication is how passionately people defend things that makes no sense.  The point is that beliefs that are completely invulnerable to evidence and passionately defended can be quite durable.  It has nothing to do with fundamental logic." Colm O'Shea

"Humans in general are biased to look for confirmatory evidence. When someone is bullish oil, they tend to pick out the pro-oil arguments in whatever they read. Very few people train themselves to look for dis-confirming evidence. Psychologists have done tests about how humans approach problem solving and found we are somehow pre-programmed to look for confirmation and not dis-confirmation. What I try to do is look for dis-confirming evidence. It's a very difficult practice and I have to continually train myself to ask why I believe something is going to go down, not why it should go up." Jim Leitner

“We try and avoid the worst anchoring effect which is always your previous conclusion. We really try and destroy our previous ideas.” Charlie Munger

"Anchoring is a subtle and pervasive aberration in investment thinking." Ed Thorp

"If we only look to confirm our beliefs, we will never discover if we're wrong.  Be self critical and unlearn your best-loved ideas.  Search for evidence that dis-confirms ideas and assumptions.  Consider alternative outcomes, viewpoints and answers." Peter Bevelin

"Charles Darwin used to say that whenever he ran into something that contradicted a conclusion he cherished, he was obliged to write the new finding down within 30 minutes. Otherwise his mind would work to reject the discordant information, much as the body rejects transplants. Man's natural inclination is to cling to his beliefs, particularly if they are reinforced by recent experience." Warren Buffett

"Confirmation bias - believing what you want to believe and discounting contrary information - it has destroyed countless portfolios and businesses alike." Scott Fearon

"We were also well aware of the dangers of what social psychologists call confirmatory bias, in other words the tendency to collect all the information that agrees with your position and to ignore the information that doesn't.  Behavioural theory teaches that the best antidote to this bias is to listen to the opposite side of the case and then dispassionately to identify the logical flaws in the argument." Barton Biggs

“You have to be very careful of ‘commitment bias’. A smart investor described it as the proclivity of investors to be very critical of ideas they don’t own and to read very dismissively of prospects of things not yet owned. But once owned to then view everything about a company in your portfolio favourably, as confirmation about why you own something. That’s something I try to guard against.” Thomas Russo