BiasBelief updating · Confirmation Bias · Entry 23
Experimenter’s Bias – when you see only what you expect
Do you only notice results that confirm your hypothesis? That’s Experimenter’s Bias – the tendency to give more weight to data that aligns with expectations while downplaying or ignoring conflicting results.
Where it can show up
- Science – a researcher ‘accidentally’ focuses only on data that supports their theory while dismissing the rest as error.
- Medicine – a doctor believes a new drug works, so they notice only improvements while ignoring failures.
- Workplace – a manager assumes certain employees are more capable and notices only their successes while overlooking others’ potential.
A practical countermeasure
- Question your expectations – do you want your hypothesis to be right, or do you want the truth?
- Accept all data, not just the convenient ones – inconvenient results may be more valuable than expected ones.
- Trust the numbers, not intuition – our perception adapts to expectations, but statistics remain objective.
