“Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so.” — Douglas Adams

Adams wrote that observation about human nature generally. It applies with particular force to markets. The research is available. The track records are public. The failure rates of discretionary trading are well documented. And yet the vast majority of market participants continue making the same predictable errors, driven by the same cognitive biases, year after year. For trend followers, that predictability is not a problem to lament. It is the source of the opportunity.

Confirmatory Bias

Confirmatory bias is the tendency to give greater weighting to information that supports our pet theories and beliefs, while minimizing disconfirming information. People have a natural tendency to filter information in a way that favors their preferred views. Many a failed business venture can be linked with the way in which the proprietor neglected unsupported information about prospects and overly inflated data favoring the venture.

In markets, confirmatory bias shows up constantly. A trader who believes a stock is undervalued will seek out analysts who agree, dismiss those who do not, and interpret ambiguous news as confirmation of the thesis. The position gets held long past the point where the evidence supports it because every data point is being filtered through a lens that favors the original conclusion. The market, which has no opinion and no preference, continues moving against the position. The trader continues holding, because to exit would mean admitting the thesis was wrong, and the bias prevents that admission.

A mechanical trend following system has no thesis to confirm. It reads price. If price is moving up with sufficient strength, the system is long. If price reverses past the exit level, the system exits. No interpretation, no filtering, no preferred view. The confirmatory bias has nothing to attach to because the decision is made by the rules, not by the trader’s beliefs about what the market should do. More on how the TurtleTrader rules encode this principle.

Causality Bias

Causality bias is the natural human tendency to view the world as an organized, patterned environment where everything occurs for a reason. This perceptual quality is often extended into areas where such principles do not apply. The best example of this is gambling. Gamblers are very good at perceiving patterns and cause-effect relationships where there are no such processes operating. This bias can result in misjudgment of risks and the development of flawed spending and investment strategies.

Markets attract causality bias in enormous quantities. Every price move gets a reason attached to it after the fact. The market fell because of the Fed meeting. The market rallied because of earnings. Analysts and financial media compete to provide the most plausible-sounding causal story for each day’s price action. The stories are almost entirely retrospective and almost entirely irrelevant to what happens next. The market moved. The story was invented afterward to explain it.

Trend following is built on the explicit rejection of causality narratives. Price is not explained. It is measured. Whether crude oil falls because of geopolitical tension or weather patterns or a supply glut is irrelevant to a trend follower who reads the price decline and goes short. The cause does not change the trade. Only the price movement matters, and the rules respond to it without requiring an explanation. This is why the approach is reactive by design and why it works across markets that have nothing in common fundamentally. The Metallgesellschaft case is a documented example of trend followers profiting from a large price move they had no causal knowledge of.

Group Think Bias

Group think bias is where individuals in an organization overvalue particular ideas and decisions because of peer support. For example, a CEO may have a particular view and staff eager to facilitate career advancement may distort their own evaluation of the proposal to fit in with what they perceive the boss expects.

In financial markets, groupthink produces consensus positions that become dangerously crowded. When everyone in an institution agrees that a particular trade or asset is attractive, the dissenting voices get drowned out. The position builds beyond what any objective analysis would support, and when it unwinds it does so violently. Groupthink was a feature of every major market crisis: the dot-com bubble, the mortgage-backed securities consensus of 2006 and 2007, and countless other episodes where the collective agreement of smart people produced catastrophically wrong outcomes.

Trend followers operate outside institutional consensus by design. The system does not ask what other people think about a market. It asks what the price is doing. When a trend follower takes a position that runs counter to the prevailing consensus, they are not being contrarian for its own sake. They are following the price signal, which sometimes leads in the same direction as the consensus and sometimes does not. The independence from groupthink is structural, not attitudinal. The rules make the decision, and the rules have no access to what everyone else believes.

Why These Biases Mean Trend Followers Win

Losing traders have these biases. They are key reasons why trend followers win. As long as people fall prey to these biases, there will be opportunity to win their trading losses and profit in the great zero sum game.

That paragraph is the complete argument. Markets are zero-sum in aggregate. Every dollar gained by one participant is lost by another. Trend followers win consistently because they have removed the primary sources of error that cause other participants to lose consistently. Confirmatory bias produces traders who hold losing positions too long. Causality bias produces traders who react to stories rather than prices. Groupthink produces institutions that build positions far beyond what the evidence supports. Each of those behaviors creates the counterparty that systematic trend following needs. The biases do not disappear. Human psychology does not change. The opportunity persists. For the full story of how this was first demonstrated systematically, see the TurtleTrader story.

Feedback from Clients and Visitors

“Absolutely spot on. Great site, and great to see some honest people working in finance, what a refreshing rarity you are.” — Financial Advisor, Standard Life

“I found that your site combined with the book was so full of helpful instruction and information that I never had to ask for extra support. I’d been trading for a few years using technical analysis and was getting nowhere. Your easy K.I.S.S. approach with trend following and risk management has not only kept me from big losses, it has given me bigger gains. I’m actually making money, spending much less time looking at charts, and having fun!” — TurtleTrader Student

“Just wanted to say thank you…I am now beating all the averages, have happy clients and have employees who finally have a methodology that we believe in. Thanks. Your site is great.” — TurtleTrader Student

“Hello, I have been on your site for the last two days straight. It’s like a great novel I can’t seem to put down! Awesome site. I will definitely be e-mailing future thoughts and comments as I continue through the site. Thanks for a great site, and the dedication you have made to cutting through all the BS and making the information available the way you do!” — Financial Advisor, Raymond James Financial Services, Inc.

“The design of this system is really elegant and thoughtful. I’m a computer systems builder by trade, and to me, good systems are the ones that are really focused. Good systems try to keep things as simple as possible to keep the user concentrating his efforts in doing a few very effective things very well. They have a tremendous amount of smart thought behind them, and much of this effort goes into eliminating useless background noise (which in trend followers’ case would be fundamental analysis). It’s kind of like watching a skilled professional athlete, they make it look so easy but that’s because of the discipline and thousands of hours of sweat they put into the work.” — Derek

“Holy smokes guys, this is the first site I have come across that thinks like I do. You seem to tell it like it is, guaranteed there will be winners and losers, period. I work in the energy sector and have always positioned futures and options from a hedger’s perspective but deep down I have always had an interest in market efficiencies and how to profit from it without getting greedy and stupid. There is no sicker feeling than to get popped in the marketplace. Every web site out there seems to have a deal or no-brainer. This web site seems to be the first that I have come across that mentions that you have to be smart and you have to work, there are no shortcuts.” — Jeff T.

“Greetings, I must express my sincere appreciation for TurtleTrader. The amount of trading misinformation prevalent on the web and in the media can really hurt an individual trader. Your site manages to dispel a lot of trading myths as well as educate traders at the same time.” — Grant S.

Frequently Asked Questions

What is confirmatory bias and how does it hurt traders?

Confirmatory bias is the tendency to give more weight to information that supports existing beliefs and less weight to information that contradicts them. In trading it causes traders to hold losing positions too long, dismiss contrary evidence, and interpret ambiguous data as confirmation of their thesis. A systematic trading system eliminates this bias by making decisions based on price rules rather than the trader’s beliefs.

What is causality bias in financial markets?

Causality bias is the tendency to assume that every event has an identifiable cause and to seek out cause-and-effect explanations even where none exist. In markets it produces traders who react to news narratives rather than price reality. Trend following rejects causality narratives entirely, treating price movement as the only relevant input regardless of the story attached to it.

How does groupthink bias create opportunity for trend followers?

Groupthink causes institutions to build consensus positions that become dangerously crowded and eventually unwind violently. Trend followers operate outside institutional consensus by following price signals rather than collective opinion. When a crowded consensus position reverses, the price move is typically large and sustained, exactly the kind of move a trend following system is built to capture.

Why do these biases persist if traders know about them?

Because knowing about a bias and being immune to it are different things. Douglas Adams observed that humans are remarkable for their disinclination to learn from others’ experience. The biases are deeply wired into human psychology. Understanding them intellectually does not prevent them from operating emotionally under pressure. Only a mechanical system that removes real-time human judgment from the decision can reliably prevent them from affecting trading outcomes.

Is trend following profitable because other traders are irrational?

Partly, yes. Markets are zero-sum in aggregate. Trend followers win consistently because the systematic approach removes the primary sources of error that cause other participants to lose. Confirmatory bias, causality bias, and groupthink each produce predictable losing behaviors that create the counterparty opportunities trend following exploits. As long as human psychology remains constant, those opportunities persist.

Trend Following Systems
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