Every one makes investment mistakes. From the time we were born, we learned from the mistakes we made. As investors, we need to learn from our investment mistakes by recognizing when we make them and make the appropriate adjustments to our investing discipline. When we make a losing investment, do we recognize our investing mistake and learn from it, or do we attribute it to some outside factor, like bad luck or the market? To make money from your investments and beat the market, we must recognize our investing mistakes and then learn from them. Unfortunately, learning from these investing mistakes is much harder than it seems.Some of you may have heard of this experiment. It is an example of a failure to learn from investing mistakes during a simple game devised by Antoine Bechara. Each player received $20. They had to make a decision on each round of the game: invest $1 or not invest. If the decision was not to invest, the task advanced to the next round. If the decision was to invest, players would hand over one dollar to the experimenter. The experimenter would then toss a coin in view of the players. If the outcome was heads, the player lost the dollar. If the outcome landed tails up then $2.50 was added to the player’s account. The task would then move to the next round. Overall, 20 rounds were played.In this study there was no evidence of learning as the game went on. As the game progressed, the number of players who elected to play another round fell to just over 50%. If players learned over time, they would have realized that it was optimal to invest in all rounds. However, as the game went on, fewer and fewer players made decisions to invest. They were actually becoming worse with each round. When they lost, they assumed they made an investing mistake and decided to not play the next time.So how do we learn from our investing mistakes? What techniques can we use to overcome our “bad” behavior and become better investors? The major reason we don’t learn from our mistakes (or the mistakes of others) is that we simply don’t recognize them as such. We have a gamut of mental devices set up to protect us from the terrible truth that we regularly make mistakes. We also become afraid to invest, when we have a losing experience, as in the experiment above. Let’s look at several of the investing mistake behaviors we need to overcome.I Knew ThatHindsight is a wonderful thing. As a Monday morning quarterback, we can always say we would have made the right decision. Looking again at the experiment mentioned above, it is easy to say, “I knew that, so I would have invested on each flip of the dice”. So why didn’t everyone do just that? In my opinion, they let their emotions rule over logical decision-making. Maybe their last several trades were losers, so they decided it was an investing mistake and they become afraid to experience another losing trade.The advantage of hindsight is we can employ logic as we evaluate the decision we should have made. This allows us to avoid the emotion that gets in our way. Emotion is one of the most common investing mistake and it is the worst enemy of any good investor. To help overcome this emotion, I recommend that every investor write down the reason you are making the decision to invest. Documenting the logic used to make an investment decision goes a long way to remove the emotion that leads to investment mistakes. To me the idea is to get into the position where you can say “I know that” rather than I knew that. By removing the emotion from your decision, you are using the logic you typically use in hindsight to your advantage.Self CongratulationsWhenever we make a winning investment, we congratulate ourselves for making such a good decision based on our investing prowess. However, if the investment goes bad, then we often blame it on bad luck. According to psychologists, this is a natural mechanism that we, as humans possess. As investors, it is a bad trait to have as it leads to additional investing mistakes.To combat this unfortunate human trait, I have found that I must document each of my trades, especially the reason I am making the decision. I can then assess my decisions based on the outcome. Was I right for the right reason? If so, then I can claim some skill, it could still be luck, but at least I can claim skill. Was I right for some spurious reason? In which case I will keep the result because it makes me a profit, but I shouldn’t fool myself into thinking that I really knew what I was doing. I need to analyze what I missed.Was I wrong for the wrong reason? I made an investing mistake, I need to learn from it, or was I wrong for the right reason? After all, bad luck does occur. Only by analyzing my investment decisions and the reasons for those decisions, can I hope to learn from my investing mistakes. This is an important step toward building genuine investment skill.Luck Becomes InsightThe market is comprised of a series of cause and effect actions, which are not always transparent. This cause and effect has created some interesting behaviors by some very successful people. For example, some baseball pitchers are known to not step on the white chalk line when they are playing. I am sure you have heard of many “superstitions” that people hold to be true to help them perform well.In an experiment by Koichi Ono’s in 1987, subjects were asked to earn points in response to a signal light. They could pull three levers, though they were not told to do anything in particular. They could see their score on a counter, but did not know that points were awarded completely independent of what they did. Nothing they did influenced the outcome in terms of points awarded. During the experiment, they observed some odd behavior as the participants tried to make the most points possible. Most subjects developed superstitious behavior, mainly in patterns of lever pulling, but in some cases, they performed elaborate or even strenuous actions. Each of these superstitions began with a coincidence. In some cases, the participants would pull levers in a particular sequence. In other cases, even more odd behavior was observed, including a person who jumped off a table and then later jumped up to touch the ceiling to “score” points. Keep in mind the points were awarded either on a fixed time schedule or on a variable time schedule, not based on the action of the participant.The point of this is that as humans we tend to think that luck is insight. We fail to analyze effectively the situation and the real reason for our success or failure. In investing this behavior will lead to ruin. To help overcome our natural tendency, we must document our investing decisions and then assess the results. This assessment process helps us learn from our success and from our failures and is critical for each of us if we hope to become successful investors.Learn from Investment MistakesTo help avoid investing mistakes, what should you document before you make an trade? I like to look at three categories regarding a stock I am considering. First, I look at a series of fundamental information such as earnings yield, return on capital, revenue growth, insider holdings, sector, and free cash flow. The fundamental information helps me identify if this is a good company with growing earnings, good management and has potential. After reviewing the appropriate financial information including SEC documents, I identify the risks inherent in the company. These risks might include competition, market share, insider transactions, and any litigation that the company is experiencing. Here one needs to try to identify every possible risk and assess them critically. Finally, I look at the chart of the stock, seeking to identify support and resistance zones. This gives me potential entry points, exit targets, and the trailing stop loss. I complete these sections with a written trading strategy describing how I expect to make my trades. All these investment factors should be documented before making a trade. Once the trade is complete, I review them to see what I can learn so I can avoid any investing mistakes in the future.To learn from our investing mistakes, we need to document our actions before we make the decision. We also need to be honest with ourselves when assessing our results. As we have seen, it is quite easy for each of us to put on rose-colored glasses and think we are better investors than we really are. We need to assess critically our investing abilities without distorting the feedback we receive from our decisions. Those of us who are able to learn this valuable skill will benefit greatly. Those of us who are unable to apply this learning will be destined to mediocrity at best and likely lose much of their capital before they quite investing.