The Semmelweis reflex is a cognitive bias that describes the tendency to reject new evidence because it contradicts established norms or beliefs. This phenomenon is named after Ignaz Semmelweis, who, in the 19th century, discovered that handwashing dramatically reduced childbed fever mortality rates, but faced rejection from his contemporaries due to their adherence to existing medical beliefs.
Despite Semmelweis providing strong evidence for hand hygiene, many doctors continued to dismiss his findings, believing in miasma theory and other outdated concepts, illustrating the Semmelweis reflex in action.
To overcome the Semmelweis reflex, individuals must engage in critical thinking and reflect on their beliefs, being open to changing them in light of new evidence.