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Clearer Thinking Team

Observer-Expectancy Effect: Definition, Examples and Effects

The Semmelweis Reflex is a phenomenon that occurs when people reject new ideas or discoveries that contradict their existing beliefs. Named after the Hungarian doctor Ignaz Semmelweis, who discovered the importance of handwashing in preventing the spread of disease, the Semmelweis Reflex is a powerful force that can prevent progress and impede scientific advancement. Here is a closer look at the definition, examples, and effects of the Semmelweis Reflex.


Definition: The Semmelweis Reflex is a psychological phenomenon in which people reject new ideas or discoveries that contradict their existing beliefs. It is named after the Hungarian doctor Ignaz Semmelweis, who discovered the importance of handwashing in preventing the spread of disease.


Examples: One of the most famous examples of the Semmelweis Reflex is the rejection of Ignaz Semmelweis’s discovery that handwashing could prevent the spread of disease. Despite the fact that his discovery was backed up by scientific evidence, it was rejected by the medical community at the time. Another example is the rejection of the germ theory of disease in the 19th century, which was met with skepticism and disbelief.


Effects: The Semmelweis Reflex can have a significant impact on scientific progress and advancement. By rejecting new ideas and discoveries, people can prevent progress and impede the development of new treatments and cures. Additionally, the Semmelweis Reflex can lead to a lack of trust in science and scientific institutions, which can have a negative impact on society.


Overall, the Semmelweis Reflex is a powerful psychological phenomenon that can prevent progress and impede scientific advancement. By understanding the definition, examples, and effects of the Semmelweis Reflex, we can better recognize and address this phenomenon in order to promote scientific progress.


Do you want to expand your knowledge on this topic? Read our full in-depth article on cognitive biases.


Do you have extra 15 minutes today? Takeour fun and interactive quiz to learn which of 16 reasoning styles you use, your overall level of rationality, and what you can do now to improve your rationality skills.

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