Normalcy bias

The brain sometimes ignores multiple warnings signals. This leads to people not believing or minimizing threat warnings. Eg. People ignoring flood warnings.


Research suggests that even when the brain is calm, it takes 8–10 seconds to process new information. Stress slows the process, and when the brain cannot find an acceptable response to a situation, it fixates on a single and sometimes default solution that may or may not be correct. This could be why the brain stays in denial mode instead of acting on the warning.


  • The normalcy bias can explain why, when the volcano Vesuvius erupted, the residents of Pompeii watched for hours without evacuating. It can explain why thousands of people refused to leave New Orleans as Hurricane Katrina approached.
  • The lack of preparation for disasters often leads to inadequate shelter, supplies, and evacuation plans.