Which things traders say about the mind are actually true?

Why this matters. This subject is the part of markets education most contaminated by confident nonsense. Being able to sort it yourself is worth more than any individual finding in this domain.

Everything in these three courses carried a label. There were five of them.

The five tiers

Conceptual frame. A distinction that organises thinking rather than reporting a measurement, and presented as such. Knight on risk against uncertainty. Hogarth's kind and wicked learning environments. Kahneman and Klein's condition on intuition. A frame cannot be replicated because it was never a result; it earns its place by being useful, and it is the tier most often mistaken for the first.

Replicated. Named finding, named researchers, evidence base stated. Prospect theory's value and weighting functions. Sunk cost and escalation of commitment. Mental accounting. Myopic loss aversion. Ambiguity aversion. Implementation intentions.

Documented but thin. Named, with the limitation in the same breath. Coates and Herbert on hormones — seventeen traders, eight days. Lo and Repin on physiology — ten subjects. Real measurements, small samples, no general claim.

Folklore. Taught only so you recognise it, never prescribed. The arousal-performance curve applied to trading: mice, electric shock, and an extrapolation the original does not support. "Twenty-one days to form a habit" — the modelled range in that study was 18 to 254 days.

Practitioner testimony. What real operators say they did, held apart from evidence: testimony is data about what this person did and believed, not evidence that you should do the same.

What was removed, and why it is worth knowing

Ego depletion — a 23-laboratory preregistered replication returned d = 0.04, interval spanning zero. The "hungry judges" result — the most quoted finding in this area, with its magnitude challenged as a possible artifact of case ordering.

Both are still cited constantly in trading writing. Meeting them here first is the point.

One removal in the other direction. Gilovich, Vallone and Tversky (1985) declared the "hot hand" an illusion: shooting streaks were no longer than chance. Miller and Sanjurjo (2018) showed the original test was biased by how streaks were sampled, and that a modest, real hot hand had been hidden by the method. That does not restore streak-reading in markets; Course 2 measured a broad fund's losing runs and found them shorter than a coin's. It means a debunking carries a tier like any claim, and "it is all noise" can be folklore too.

The tell that survives everything

Survivorship. Interview collections select on having already succeeded, so what unsuccessful people doing the identical thing would have said is missing by construction. That does not make the interviews useless — it makes them testimony.

The artefact

A tier label on anything you adopt. One word beside the claim: replicated, thin, folklore, testimony.

You will find that a surprising amount of what you already believe has no tier at all, and that finding out costs nothing.

Try it now

Take three things you believe about trading psychology and assign each a tier. Whichever resists labelling is the one to examine.