Confirmation Bias

Buy a stock and watch what happens to your information diet within a week. Bullish articles feel insightful. Bearish ones feel poorly reasoned, or biased, or "already priced in." Twitter threads agreeing with you get bookmarked; disagreeing ones get scrolled past with a micro-sneer you don't even notice. You believe you're researching. You're actually shopping — for agreement.

That's confirmation bias: the automatic tendency to seek, notice, and over-weight evidence that supports what you already believe, while filtering, doubting, and forgetting evidence against it. It's not lying to yourself — it's worse: it's honest selective vision. System 1 does the sorting before "you" ever see the material, so the world genuinely appears to agree with you.

Where it bills traders, specifically: the position flips your role from judge to defense lawyer. Before entry, you weighed both sides (maybe). After entry, your identity is invested, and every new fact gets processed by the question "how does this fit my thesis?" instead of "what does this mean?" This is why adding to losers feels researched — you've spent a week collecting supporting exhibits. It's why obvious sell signals get reinterpreted ("that CHoCH is just a shakeout"). And it's turbocharged by the modern feed: every platform's algorithm learns what you engage with and serves you more of it — confirmation bias with a recommendation engine attached. Hold a position for a month and your entire information environment has been custom-built to agree with you.

It also explains a Fundamental Analysis school trap from the inside: the "story stock" that's obviously broken to everyone except its holders. The holders aren't stupid — they're informed, catastrophically, by a filtered stream.

Defense — assign the prosecution. You cannot will yourself into neutrality (the sorting happens pre-consciously), so build the opposing counsel structurally: (1) Write the bear case at entry — your Fundamental Analysis school's Question 8 ("why might I be wrong?") is literally an anti-confirmation device; a thesis without a written kill-condition is a religion, not a position. (2) Pre-define what would change your mind — a specific price, level, number, or event, written in QbarTrade before entry, so the exit decision was made by the judge, not the lawyer. (3) Deliberately read one strong opposing view per position per week — not to be swayed, but to keep the sorting machinery honest. Charlie Munger's standard (from your Legendary Traders school) is the gold version: you're not entitled to an opinion until you can state the other side better than its supporters can.

Offense — crowded conviction is fragile. When an entire crowd has confirmation-filtered its way into one loud consensus (every headline bullish, every dip "a buying opportunity"), disconfirming reality eventually arrives all at once — to people structurally unprepared for it. That's the behavioral fuel inside your FA school's expectations game (priced-for-perfection stocks cracking on fine results) and inside exhaustion gaps (Market Structure school): the last buyers were the best-informed-agreed-with people in the room.