The Semmelweis Reflex: The gap between rejection and knowledge

” The greater the ignorance the greater the dogmatism “

Wiiliam Osler, Canadian physician, and one of four founders of Johns Hopkins Hospital

 In one of the previous posts, The Men Who Mistook p Values for Significant Results,  we explored how cognitive biases, statistical fallacies and misinterpretation of scientific research have plagued current critical thinking both in clinical medicine and research, and how we blindfoldedly accept statistical analysis as a proof that a scientific research is valid and reliable. But the “Semmelweis Reflex” gives a complete opposite view to the current state of affairs. Before diving into this matter, it would be interesting to take a look at the history behind this metaphor.

Ignaz Semmelweis, a Viennese physician who was born in 1818 came to Budapest to work at Rokus Korhaz Hospital [3]. He soon noticed that 1 in 3 women who came to the maternity unit to give birth died of puerperal fever (a.k.a childbirth or childbed fever).  After accurate observations he was convinced that poor hygiene was the main common denominator in all those mortality cases and soon started a rigorous cleanliness campaign, including washing hands, linens, and instruments between each patients. In the next 6 years he was able to lower the number of deaths from 30% to less than 1%.

He tried to convince other physicians, that they need to adopt his techniques in order to reduce mortality at hospitals, but no one listened to him, perhaps mainly because he could not explain how exactly these techniques reduced mortality. Unfortunately, he died at the age of 47 and never saw the impact of his observations and techniques[1,2] . Legend has it that after long bouts of depression and anger, his wife convinced him to go back to Vienna and visit a friends hospital, but he never came home, and was institutionalized at the same lunatic asylum until he died from the same condition as his patients on the maternity unit, septicemia.[1]

Had he read Louis Pasteur’s paper on the causes of fermentation, and bacteriology, he might have been able to explain to his colleagues, what Joseph Lister did in the same year as Semmelweis’s death.[2]

History aside, in the scientific and medical communities the acceptance rate for new methods and therapies are quite low, and the statistical analysis is a way to communicate research findings with the rest of the community to gain acceptance and eventually implementing those methods, skills and knowledge in the real world.  The dogmatic rejection of new research and techniques, or even what we call it now a days a ” Journal Club” where we rip apart any kind of research regardless of the main ingredients, is an example of the “Semmelweis Reflex” . Semmelweis Reflex is another way of describing dogma, and keeping an open and knowledgeable mind. It is a unique characteristic that not everyone posses in the scientific community.

Dogma itself has an evolutionary root in our neural networks, and just like the pattern recognition and data chunking serve a purpose, (which  will be explored in future posts under the topic of central dogma in neurobiology purposed by Ramon Y Cajal) dogma isa useful trait, or at least used to be during evolution  [4]. Dogma itself, as a trait, interferes with the general rule of plasticity, which will be explored in future posts.


[1] N. C. for B. Information, U. S. N. L. of M. 8600 R. Pike, B. MD, and 20894 Usa, Historical perspective on hand hygiene in health care. World Health Organization, 2009.
[2] H. J. Lane, N. Blum, and E. Fee, “Oliver Wendell Holmes (1809–1894) and Ignaz Philipp Semmelweis (1818–1865): Preventing the Transmission of Puerperal Fever,” Am J Public Health, vol. 100, no. 6, pp. 1008–1009, Jun. 2010.
[3] “Szent Rókus Kórház.” [Online]. Available: [Accessed: 14-Mar-2017].
[4] L. Colucci-D’Amato, V. Bonavita, and U. di Porzio, “The end of the central dogma of neurobiology: stem cells and neurogenesis in adult CNS,” Neurol. Sci., vol. 27, no. 4, pp. 266–270, Sep. 2006.

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