🧠 8 · Kereskedési pszichológia és mindset

🧩 Module 1: Cognitive Biases in Trading

8 cognitive biases that cost traders money — and how to recognize them

1. Cognitive Biases in Trading

1.1 Dual-Process Theory: How Your Brain Makes Decisions

Daniel Kahneman, 2002 Nobel laureate in economics, describes two fundamental thinking systems in Thinking, Fast and Slow (2011):

System	Properties	In Trading
System 1 — Fast	Intuitive, automatic, emotion-driven, energy-efficient	Impulsive decisions, gut feeling, errors under stress
System 2 — Slow	Analytical, deliberate, rule-based, energy-intensive	Plan-conforming trading, rule checking, rational analysis

The problem: markets are designed to maximally activate System 1 — red and green prices, real-time P&L, click buttons. Anyone who does not actively counteract this trades from System 1.

"The greatest source of trading errors is not the strategy, but the failure to follow one's own rules." — Brett Steenbarger, The Psychology of Trading

1.2 The 8 Most Important Biases in Trading

😰 Loss Aversion

Losses are weighted about 2.5× more strongly than equivalent gains (Kahneman & Tversky, 1979).

Stop-loss is not executed; losers get reclassified as "investments" and held further.

CounterstrategyAlways define stop-loss before entry and stick to it without compromise.

🔍 Confirmation Bias

Only confirming information is noticed; opposing signals are dismissed.

Bearish divergences and volume warnings on a long position are systematically ignored.

CounterstrategySteelman technique: actively formulate the strongest counter-argument to your thesis.

😎 Overconfidence

Your own skills are overestimated — especially after a winning streak (Dunning-Kruger effect).

After 5 winning trades, position size is doubled — "the market is on my side."

CounterstrategyFixed risk rules, no exceptions. Position size stays constant.

📅 Recency Bias

Recent events are dramatically over-weighted compared to objective probability.

After 3 up days the uptrend is considered "safe" — mean reversion is ignored.

CounterstrategyUse backtest data instead of current sentiment. Evaluate setups by defined criteria.

⚓ Anchoring

Fixation on a reference price — often your own entry price, which the market does not know.

Stop-loss is placed at "−10% from my entry" — instead of at a technical level.

CounterstrategyTechnical levels determine entry and exit — not your purchase price.

🔮 Hindsight Bias

In hindsight, everything seems predictable — "it was obvious!" distorts your ability to learn.

After a crash you believe you saw the signs — even though you were unsure beforehand.

CounterstrategyAlways write predictions down before the event and compare honestly afterward.

⚖️ Disposition Effect

Winners are realized too early, losers held too long (Odean, 1998).

+5% is taken immediately, −15% is "ridden out until it comes back."

CounterstrategyTrailing stop for winners, consistent stop-loss for losers.

📈 FOMO

Fear of Missing Out — entering live moves out of fear of missing something.

Entering a breakout that has already run +25% — usually right before the reversal.

CounterstrategyWait for the next valid setup. There is always another trade.

Study: Odean (1998) analyzed 10,000 brokerage accounts: stocks investors held (losers) subsequently underperformed by 3.4% p.a. compared to the ones they sold (winners). The Disposition Effect costs measurable returns.

1.3 Bias Check: Which Bias Dominates for You?

Answer the 8 situational questions honestly. There are no right or wrong answers.

🧩 Bias Check

1.4 Pre-Trade Bias Audit

5 questions you should ask yourself before every trade:

Is this trade based on my defined setup — or on a "feeling"?
Have I heard and weighed the strongest counter-argument to this trade?
Did I define my stop-loss level BEFORE entering?
Is my last trade (win or loss) influencing my current decision?
Am I entering because the setup fits — or because the price "is just running"?

💡 Rule of thumb: If you answer 2 or more questions with "no" after the audit, wait for a better setup.