Investment psychology
People are neither fully rational nor completely selfish

I offer an explainer that looks at the key ways psychological problems confound us as investors. I also offer a list of practical things we can do to overcome them.
The practical things are what Daniel Kahneman (Nobel Prize in economics) calls risk policies. Kahneman describes risk policies as decision rules that are always applied in similar situations. Examples he gives are in the insurance context: “always take the highest possible deductible when purchasing insurance” or “never buy extended warranties.”
Some think investment psychology is all about controlling our emotions. In fact that is only a very small part of it. One happy thought is that most other investors, including the professionals, also suffer from the same foibles. Once our investor psychology education is complete, we have a decided edge in the market. It is what I call the behavioral edge.
The great investors and investment psychology
To set the scene, let’s look at the ideas of some investing greats.
Keynes wrote in the 1930s: “It might have been supposed that competition between expert professionals, possessing judgment and knowledge beyond that of the average private investor, would correct the vagaries of the ignorant individual left to himself. It happens, however, that the energies and skill of the professional investor and speculator are mainly occupied otherwise. For most of these persons are, in fact, largely concerned, not with making superior long-term forecasts of the probable yield of and investment over its whole life, but with foreseeing changes in the conventional basis of valuation a short time ahead of the general public.” (Keynes, 1936,2007)p.154.
What Keynes is talking about here is the investment industry’s focus on the short term. This is caused by what psychologists call the behavioral bias of ‘narrow framing’.
The old time investors knew a lot about investment psychology. Bernard Baruch is reported to have said: “Without due recognition of crowd-thinking (which often seems crowd-madness) our theories of economics leave much to be desired.” (Lowenstein, 1995,2008)p.306 In future posts we will look more deeply into the ever present danger of herd mentality, madness of crowds and groupthink. These are all behavioral biases that bedevil us.
Everybody knows about Ben Graham’s funny little fellow with incurable psychological problems called Mr. Market. As Warren Buffett explained in the 1987 Berkshire Hathaway letter to shareholders: “At times he feels euphoric and can see only favorable factors affecting the business. When in that mood, he names a very high buy-sell price because he fears that you will snap up his interest and rob him of imminent gains. At other times he is depressed and can see nothing but trouble ahead for both the business and the world. On these occasions he will name a very low price, since he is terrified that you will unload your interest on him.” Mr. Market suffers from a host of behavioral biases, including anchoring, priming, risk seeking behavior, risk aversion, herding and many more.
Peter Lynch one of the great investment managers of the 20th century wrote: “Things inside humans make them terrible stock market timers. The unwary investor continually passes in and out of three emotional states: concern, complacency, and capitulation. He’s concerned after the market has dropped or the economy has seemed to falter, which keeps him from buying good companies at bargain prices. Then after he buys at higher prices, he gets complacent because his stocks are going up. This is precisely the time he ought to be concerned enough to check the fundamentals, but he isn’t. Then finally, when his stocks fall on hard times and the prices fall to below what he paid, he capitulates and sells in a snit.” (Lynch, 1989,1990)p.70. Lynch is talking about what today behavioral psychologists would call, amongst other things, overconfidence, risk seeking and risk avoidance behaviors. These are all pathological behavioral biases.
To bring us up to date here’s something Howard Marks has written: “Whereas the key to ascertaining value is skilled financial analysis, the key to understanding the price/value relationship – and the outlook for it – lies largely in insight into other investors’ minds. Investor psychology can cause a security to be priced just about anywhere in the short run, regardless of its fundamentals.” (Marks, 2013)p.32. These can be caused by halo effect, wysiwyg, priming, anchoring and so on. Readers don’t have to understand all these terms at the moment.
If it wasn’t for the weird impact of investor psychology, the stock market would be fairly efficient. As it is, the stock market gyrates quite erratically. It is essentially a messy and inefficient affair. See my thoughts here on inefficient markets.
Psychological explanation
In the early 1970s, Amos Tversky and Daniel Kahneman, two Israeli psychologists, started working together on the subject of people’s attitudes to risky choices. The standard theory in psychology at the time, indeed in all social sciences including economics, was the ‘expected utility theory’. In 1979, they published their results in a paper titled “Prospect Theory: An analysis of Decisions under Risk.” This was the beginning of the study and application of behavioral psychology to decision making.
Their work was all about ‘violations of rationality’, ‘decision making’ and ‘risky choices’. These are naturally of great interest to investors.
Kahneman explains: “To a psychologist, it is self-evident that people are neither fully rational nor completely selfish, and that their tastes are anything but stable. Our two disciplines [psychology and economics] seemed to be studying different species, which the behavioral economist Richard Thaler later dubbed Econs and Humans.” An Econ is a utility maximizing rational man loved by economists. (Kahneman, 2011)p.269-270. Humans are, well, human.
Mr. Market is described by Warren Buffet as having incurable emotional problems. In truth, his emotional problems are the least part of it. What he really suffers from is behavioral biases and a propensity to make cognitive errors.
Behavioral biases and cognitive errors
So what are behavioral biases and cognitive errors? Psychologists, particularly behavioral psychologists study, amongst other things, both the behavioral side and the cognitive side of Humans. The cognitive side is the mathematical, logical and rational side. Cognitive errors are errors in how we think through problems or solve problems. One example is the problem we have intuiting probabilities and drawing inferences. Investors, like all Humans, regularly make cognitive errors that contribute to poor performance. We will also see that investors, like all Humans, regularly exhibit behavioral biases that also contribute to poor performance. Behavioral biases are systematic errors in our impressions and feelings that result in quirks of behavior that one would not expect of normal rational people i.e. Econs.
Most discussions of behavioral biases and cognitive errors and investing discuss lists of biases and errors and the impact they have on investors. Experts have identified scores of biases and errors. I have come at it somewhat differently. I have identified various ways in which behavioral biases and cognitive errors harm our investing. In other posts I will go through these topics and explain the various biases and errors that are at work.
As we look at each of them I will explain how investors can overcome the problems by using decision rules and risk policies mentioned at the beginning of this post.
Other posts on investment psychology
Investors overreact to vivid memories and recent events
Explainer – herd mentality and poor investment results
Overcoming mistaken short term thinking with Kahneman style risk policies
The worst behavioral bias – jumping to conclusions
Keeping your head in times of turmoil
Investors defending against management spin and ourselves
Let’s face it, we’re really bad at patterns and statistics
Beat the behavioral gap and take advantage of Mr. Market’s foibles
The special risks of investing a windfall gain
Why is it so difficult to change our view of things?
The frailty of high conviction ideas
Do optimists make better or worse investors?
Your investment style may be stuck in a bad grove in a changing world
The joy of contrarian investing
The danger of phony correlation
The secret to keeping things in perspective
Most investors suffer from home bias
The stock market as a complex adaptive system
It doesn’t matter what high profile investors are buying or selling
Experience and becoming a really successful investor
Cut your losses is confused advice
Scatter shot estimates of fair value
Quantitative vs intuitive in investing
The inherently short-term nature of the investment management industry
Can we use heuristics to analyze a business?
The search for a better guide to stock values
Minimizing regret is a loser’s strategy
A special talent for converting life’s setbacks into future successes
Investing when others are fearful
A set of rules to develop a behavioral edge – Part 1 The problem of short-term thinking
A set of rules to develop a behavioral edge – Part 2 The attractive trap of extrapolating the most recent past into the future
A set of rules to develop a behavioral edge – Part 3 Control our animal spirits when faced with risky situations
A set of rules to develop a behavioral edge – Part 4 The herd mostly gets it wrong
A set of rules to develop a behavioral edge – Part 5 Our minds search for confirming evidence
A set of rules to develop a behavioral edge – Part 6 We generalize from limited observations
A set of rules to develop a behavioral edge – Part 7 Over-confidence and optimism bias
A set of rules to develop a behavioral edge – Part 8 Jumping to conclusions
To read more deeply on investment psychology see Part 2: Human Foibles and Investment Decision Making
Specifically Chapter 9. Great Investors and Market Psychology
Chapter 10. The Behavioral Gap
Chapter 11. Two Different Species – Econs and Humans as Investors
Want to dig deeper into the principles behind successful investing?
Click here for the Motherlode – introduction.
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