Confirmation Bias

Confirmation bias is the cognitive default. The brain spends less energy validating a belief it already holds than reconsidering it, so once a trader has formed a thesis they instinctively read the chart, the news, and the order flow through the lens of that thesis. The downside risks are still visible; they just receive less weight in the decision.

In trading this shows up as one-sided research notes, ignored stops, refusal to take a counter-thesis seriously, and continuing to add to a losing position because each new data point that fits the original story feels like fresh confirmation. The pattern is especially damaging on news-driven trades, where the same headline can be read as bullish or bearish depending on what the trader already believes.

The structural antidote is a written disconfirming-evidence test: before any trade, the trader writes down the specific price action or data point that would invalidate the thesis, and pre-commits to closing if it appears. The act of writing the disconfirmation out loud at entry is more reliable than any in-the-moment promise to stay open-minded.