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Learning path Bronze Understand and protect

Confirmation bias

Seeking and overweighting evidence that confirms an already chosen trade idea — ignoring contrary signals.

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Who it's for — Anyone who has already «decided» long or short and then hunts the chart for confirmations only — skipping objective criteria and opposite signals.

Confirmation bias can push you to notice what supports your preferred thesis and downplay or ignore what contradicts it. In trading it can weaken a structured decision process and a checklist written before entry.

In plain terms — You decided to buy and see only support; bearish signals «don't count». The chart becomes a mirror of your idea.

Confirmation bias: test the opposing thesis Four observations to examine with the same discipline: observed support and the prior trend in favor of the thesis, declining volume and negative delta as contrary evidence. No item determines the future outcome on its own. Confirmation bias: test the opposing thesis Seek supporting and contrary evidence without turning either into certainty. SUPPORTING THE THESIS Observed support Defined zone explicit rule SUPPORTING THE THESIS Prior trend Historical context not a promise CONTRARY EVIDENCE Declining volume Evidence to check do not dismiss it CONTRARY EVIDENCE Negative delta Contrary evidence needs context Cyclepedia diagram · Emiciclo
The selective filter favours evidence consistent with the thesis and overlooks contrary information.

Operational antidotes

Tool Action
Pre-trade checklist Criteria written before opening the chart
Devil's advocate Seek at least one well-founded reason not to enter
Log skipped trades and «near» entries too
External review Compare the setup with fixed rules, not the preferred narrative

Common mistake — Adding indicators until one «gives the green light» — emotional curve fitting, not analysis.

Example — Long setup: you notice support but overlook falling volume on the breakout and negative delta. Entering on visual confirmation alone leaves the decision exposed to contrary information that was excluded.

Summary card

  • What it is: selective search for confirmation.
  • Signal: you «already know» direction before the checklist.
  • Hub: Trading psychology.

Sources