The Most Important Lesson of All

Whenever I teach behavioral psychology I see the audience recognizing the mental mistakes that I am talking about. However, most of the time they recognize the mistake in others, rather than in themselves. It is always Bill the trader, or Pete the portfolio manager, who illustrates the bias rather than us. We all seem to have a bias blind spot.

For instance, a group of Americans were asked to assess how likely the average American was to make a particular mental error, and how likely they themselves were to make exactly the same mistake.¹ The bias blind spot kicked in. The survey participants thought the average American was always more likely than they were to make a mental mistake.

However, the evidence that has been collected over the course of the last three or four decades shows that all of us are likely to encounter mental stumbling blocks at some point. So the single most important lesson I could hope to share with anyone is that the biases and mistakes we are talking about in this book are likely to affect every one of us.

Why do we all suffer these behavioral biases? The answer lies in the fact that our brains have been refined by the process of evolution, just like any other feature of our existence. But remember, evolution occurs at a glacial pace, so our brains are well designed for the environment that we faced 150,000 years ago (the African savannah) but potentially poorly suited for the industrial age of 300 years ago, and perhaps even more ill-suited for the information age in which we currently live.

As Douglas Adams, author of the sublime Hitchhikers Guide to the Galaxy, said, “Many were increasingly of the opinion that they ’d all made a big mistake in coming down from the trees in the first place. And some said that even the trees had been a bad move, and that no one should ever have left the oceans.” Leaving the trees (or perhaps the oceans) may have been our first mistake, but it certainly wasn’t our last.

The Power of Star Trek

Psychologists have suggested that the best method of thinking about the way in which our brains work is to imagine that we have two different systems embedded within our minds. For the Trekkies out there, these two systems can, perhaps, be characterised as Dr. McCoy and Mr. Spock. McCoy was irrepressibly human, forever allowing his emotions to rule the day. In contrast, Spock (half human, half Vulcan) was determined to suppress his emotions, letting logic drive his decisions. Just in case you are the only person on this planet who has never come across Star Trek, the Vulcans were a humanoid species who were noted for their attempt to live by reason and logic with no interference from emotion.

The McCoy part of our brains, which we will call the X-system, is essentially the emotional approach to decision making. The X-system is actually the default option, so all information goes first to the X-system for processing. It is automatic and effortless. The judgments made by the X-system are generally based on aspects such as similarity, familiarity, and proximity (in time). These mental short-cuts allow the X-system to deal with large amounts of information simultaneously. Effectively, the X-system is a quick and dirty ‘satisfying’ system, which tries to give answers that are approximately (rather than precisely) correct. In order for the X-system to believe that something is valid, it may simply need to wish that it were so.

The Spock part of our brains, which we will call the C-system, is a more logical way of processing information. It requires a deliberate effort to actually engage this system. It attempts to follow a deductive, logical approach to problem solving. However, it can only handle one step at a time (like any logical process), so it is a slow and serial way of dealing with information. Evidence and logic will be required to make the C-system believe that something is true.

Of course, we all read this and think that we are Spock. However, the reality is that the X-system handles far more of our actions than we would be comfortable to admit. In fact, very often we end up trusting our initial emotional reaction, and only occasionally do we recruit the C-system to review the decision. For instance, when we stub a toe on a rock, or bang our head on a beam (an easy thing to do in my house), we curse the inanimate object despite the fact that it could not have done anything to avoid our own mistake!

Neuroscientists have found that the parts of the brain associated with the X-system are much older, evolutionarily speaking, than the parts of the brain associated with the C-system. This is to say we evolved the need for emotion before we evolved the need for logic. This might sound odd, but an example should help make the point obvious. Let’s pretend that I place a glass box containing a large snake on the table in front of you. I ask you to lean forward and concentrate on the snake. If it rears up you will jump backwards (even if you aren’t afraid of snakes).

The reason for this reaction is that your X-system reacted to keep you safe. In fact, a signal was generated the second your brain perceived the snake moving. The signal was sent on two different paths—a low road and a high road, if you like. The low road was part of the X-system, and sent the information straight to the amygdala (the brain’s center for fear and risk). The amygdala reacts quickly, and forces the body to jump backwards.

The second part of the signal (taking the high road) sent the information on a long loop around to part of the C-system, which processes the information in a more conscious fashion, assessing the possible threat. This system points out that there is a layer of glass between you and the snake. But you have already reacted by this time. From a survival point of view, a false positive is a better response than a false negative. Emotion is designed to trump logic.

So, Are You Spock or McCoy?

Of course, we all use both systems at various points. Indeed, the evidence suggests that those with severely impaired X-systems can’t make decisions at all. They end up spending all day in bed pondering the possibilities, without actually engaging in any action.

However, from an investment perspective we may well be best served by using our C-system. Lucky for us, we can test how easy it is to override the X-system. Shane Frederick of Yale (formerly of MIT) has designed a simple three-question test which is more powerful than any IQ test or SAT score at measuring the ability of the C-system to check the output of the X-system.² Together these three questions are known as the Cognitive Reflection Task (CRT).

Consider the following three questions:

1. A bat and a ball together cost $1.10 in total. The bat costs a dollar more than the ball. How much does the ball cost?

2. If it takes five minutes for five machines to make five widgets, how long would it take 100 machines to make 100 widgets?

3. In a lake there is a patch of lily pads. Every day the patch doubles in size. If it takes 48 days for the patch to cover the entire lake, how long will it take to cover half the lake?

Now each of these questions has an obvious, but unfortunately incorrect answer, and a less obvious but nonetheless correct answer. In question #1 the quick and dirty system favors an answer of $.10. However, a little logic shows that the correct answer is actually $.05.

In question #2 the gut reaction is often to say 100 minutes. However, with a little reflection we can see that if it takes five machines five minutes to produce five widgets, the output is actually one widget per machine per five minutes. As such, it would take 100 machines five minutes to make 100 widgets.

Finally, in question three, the most common incorrect answer is to halve the 48 days and say 24 days. However, if the patch doubles in size each day, the day before it covers the entire lake, it must have covered half the lake, so the correct answer is 47 days.

Don’t worry if you got one or all three of those questions wrong—you aren’t alone. In fact, after giving the test to nearly 3,500 people, Frederick found that only 17 percent of them managed to get all three questions right. Thirty-three percent got none right! The best performing group were MIT students; 48 percent of them managed to get all three questions correct—but that is still less than half of some of the best students in the world. I ’ve had 600 professional investors (fund managers, traders, and analysts) take these questions and only 40 percent managed to get all three questions correct, while 10 percent didn’t get any right.

What does this tell us? It tells us that all humans are prone to decision making using the X-system, and this is often unchecked by the more logical C-system. I’ve found that the number of Frederick’s questions that you get correct correlates with your general vulnerability to a whole plethora of other behavioral biases, such as loss aversion, conservatism, and impatience. Those who get zero questions right seem to suffer more pronounced examples of the biases than those who get three questions right.

Just in case you got all three questions right and are now about to abandon this book, I would caution that two very important biases seem to be immune to the power of the CRT. No matter how well you scored on the CRT you are still likely to encounter a couple of specific mental pitfalls—namely over-optimism, overconfidence, and confirmatory bias. These will be explored in the coming chapters.

X Unchecked

When are we most likely to reply upon our X-System to help us out? Psychologists³ have explored this question and come up with the following conditions which increase the likelihood of X-system thinking:

• When the problem is ill structured and complex.

• When information is incomplete, ambiguous, and changing.

• When the goals are ill defined, shifting, or competing.

• When the stress is high, because either time constraints and/or high stakes are involved.

• When decisions rely upon an interaction with others.

Now I don’t know about you, but pretty much every decision of any consequence that I’ve ever had to make has fallen into at least one or more of those categories. It certainly characterizes many of the decisions that we make when faced with an investment proposition.

One of the world ’s greatest investors, Warren Buffett, has said that investors need to learn to control their X-system, “Success in investing doesn’t correlate with IQ once you’re above the level of 100. Once you have ordinary intelligence, what you need is the temperament to control the urges that get other people into trouble in investing.”

But before we conclude that we have solved all of our behavioral errors, we should be aware that self-control (the ability to override our urges) is like a muscle—after use it needs time to recharge. To illustrate this point, think about the following experiment.⁴

You are told not to eat any food for the three hours prior to the exercise (actually timed so you have to skip lunch). When you arrive at the lab you are put into one of three groups.

The first group is taken into a room where the aroma of freshly baked chocolate chip cookies is wafting around. This room contains two trays, one laid out with freshly baked chocolate chip cookies, the other full of radishes. The group is told they can eat as many radishes as they would like, but they mustn’t eat the cookies. The second group is more fortunate. They too are faced with two trays, each containing the same foods as for the first group, but this group is told they can eat the cookies. The third group is taken to an empty room.

After 10 minutes all the groups are collected and moved to another room to take a test. The test is one of those tricky ones where you are told you must trace a shape, but do so without going over a line you have drawn before and without lifting your pen from the paper.

How do you think people from each grouped fared in the test? Those who were forced to resist the temptation of freshly baked cookies and content themselves with radishes gave up on the test in less than half the time of those from the other two groups; they also attempted just half as many problems! Their willpower had been diminished by simply resisting the temptation of cookies.

These results suggest that relying upon willpower alone is going to be tricky. Resisting the chocolate cookie that beckons to us may lead to a poor investment choice. Willpower alone is unlikely to be a sufficient defense against behavioral biases.

As Warren Buffett said, “Investing is simple but not easy.” That is to say, it should be simple to understand how investing works effectively: You buy assets for less than their intrinsic value and then sell when they are trading at or above their fair value. However, the gamut of behavioral bias that we display tends to prevent us from doing what we know we should do. As Seth Klarman observes:

So if the entire country became securities analysts, memorized Benjamin Graham’s Intelligent Investor and regularly attended Warren Buffett’s annual shareholder meetings, most people would, nevertheless, find themselves irresistibly drawn to hot initial public offerings, momentum strategies and investment fads. People would still find it tempting to day-trade and perform technical analysis of stock charts. A country of security analysts would still overreact. In short, even the best-trained investors would make the same mistakes that investors have been making forever, and for the same immutable reason—that they cannot help it.

The alternative is to ingrain better behavior into your investment approach. In the coming chapters, I will highlight some of the most destructive behavioral biases and common mental mistakes that I’ve seen professional investors make. I’ ll teach you how to recognize these mental pitfalls while exploring the underlying psychology behind the mistake. Then, I show you what you can do to try to protect your portfolio from their damaging influence on your returns. Along the way, we’ ll see how some of the world’s best investors have striven to develop investment processes that minimize their behavioral errors.

So turn the page, and we’ll start our voyage into your mind. First stop—emotions and the heat of the moment!

Chapter One

In the Heat of the Moment

Prepare, Plan, and Pre-Commit
to a Strategy

EMOTIONAL TIME TRAVEL ISN’T OUR SPECIES’ FORTE. When asked in the cold light of day how we will behave in the future, we turn out to be very bad at imagining how we will act in the heat of the moment. This inability to predict our own future behavior under emotional strain is called an empathy gap.

We all encounter empathy gaps. For instance, just after eating a large meal, you can ’t imagine ever being hungry again. Similarly, you should never do the supermarket shopping while hungry, as you will overbuy.

Now let’s imagine you are lost in some woods. As you search though your backpack you discover that you have forgotten to bring both food and water. Oh, the horror. Which would you regret more: not bringing the food or the water?

Psychologists⁵