Fear and Greed Are Not an Explanation

The short answer

"Fear and greed" is a vocabulary, not a theory. It accounts for every possible outcome after the event — you got out too early because you were fearful, you stayed in too long because you were greedy, you did nothing because you were paralysed — and that universal fit is exactly what makes it useless beforehand. A statement that cannot be wrong is not telling you anything.

This is not an argument that emotion is irrelevant. It has been measured in traders, and the measurement found something. The argument is that the finding does not say what the slogan says, and that the things which are specific enough to act on are decisions rather than feelings: how often you trade, whether a loss has been booked, whether your position size was settled before or after you entered.

What was actually measured

Lo, Repin and Steenbarger recruited eighty volunteers from a five-week online day-trading training programme. Participants filled in daily emotional-state surveys through the trading period and completed a standard personality inventory; the researchers correlated those with each participant's daily normalised profit-and-loss record.

Two results came out of it.

Intensity of reaction went with worse performance. Participants whose emotional reaction to monetary gains and losses was more intense — on the positive side as well as the negative — showed significantly worse trading performance. Subjects whose emotional states tracked their daily results more closely, feeling pleasant with gains and unpleasant with losses, tended to have worse overall profit-and-loss records.

No trader personality appeared. The standardised personality inventory revealed no specific "trader personality profile". The authors' reading of that is worth quoting in substance: it raises the possibility that trading skill is not necessarily innate, and that different personality types might perform trading functions equally well after proper instruction and practice.

The second finding is the one that should travel further than it does, because an entire category of writing and recruitment rests on the opposite assumption.

It is also a small study — eighty people, one training course, five weeks — and the authors are careful with it. When they compared the top and bottom thirds of the sample directly, they reported that the differences were not large enough to make the conclusion conclusive on their own. We cite it because it is the measurement that exists, not because it settles the question.

Why the measurement does not license the advice

Suppose the finding is exactly right: strong emotional reactivity is associated with worse results. What follows?

Not "be less emotional", which is not an action. Not "trade without emotion", which nothing in the study suggests is possible or was tested. Not that calm people make money, which is a different claim about a different variable.

What follows is narrower: something about how a person responds to gains and losses correlates with how they do. The study design cannot say which way the causation runs. It is entirely consistent with the finding that poor results produce stronger reactions rather than the reverse, and with both being driven by something else — position size, for example, which would make a given move feel larger and simultaneously make outcomes worse.

This is the general problem with the fear-and-greed frame. It takes a correlation that may not be causal and converts it into an instruction about an internal state nobody can verify you have followed.

What a mechanism looks like instead

Compare two accounts of the same trade.

A label. "I got greedy and held on too long."

A mechanism. "I did not write down an exit before entering. The position was still open, so the loss was unrealised. The research says risk-taking rises in exactly that state, and it did."

The second one is checkable. Someone can look at the record and see whether an exit was written. It also names an intervention that does not require you to change your character.

The findings in this field that have that shape are the ones this publication keeps returning to:

• Frequency. The households that traded most in the Barber and Odean data earned 11.4 per cent a year against 18.5 per cent for those that traded least. That is a count, not a mood, and it is covered in why people trade too often.
• Realised versus unrealised losses. People took less risk after a booked loss and more risk after an equivalent open one. That is a state with a timestamp, covered in the hour after a loss.
• Confidence, split three ways. What gets called confidence turns out to be at least three separately measured things that barely move together, which is covered in telling confidence from overconfidence.

Each of those names a decision rather than a feeling. That is the whole difference.

Where the emotional account does earn its place

Two qualifications, because dismissing emotion entirely would be its own kind of overreach.

First, the measurement is real. Reactivity correlated with worse performance in the one dataset that looked. If you find your reaction to a result unusually strong, that is information, even if the study cannot tell you what to do with it.

Second, emotion is a reasonable symptom to monitor even if it is a poor cause to blame. A sudden urge to double a position is not an explanation of anything, but it is a reliable cue that the size was not settled in advance — which is a mechanical fault you can fix. Used that way, as a trigger for a check rather than as a diagnosis, the feeling is useful.

What it cannot do is substitute for the decisions themselves. Those get made in advance or they get made under pressure, and what a plan has to settle beforehand is a much shorter list than most people expect.

Limits

The emotional-state study is small and its direction of causation is unresolved. The personality result is a null finding, which is weaker evidence than a positive one and should not be read as proof that temperament is irrelevant. We have not found a study showing that any particular emotional-regulation technique improves trading outcomes, and we do not claim one exists.

The wider map of what has and has not been established about trader behaviour is in our guide to the subject as a whole.

Nothing on this page is advice. Trading leveraged products carries a high risk of losing money quickly.