Semmelweis reflex

The Semmelweis reflex is a cognitive bias wherein people tend to reject new evidence or knowledge if it contradicts established norms or beliefs. Named after Ignaz Semmelweis, a 19th-century Hungarian physician who discovered that hand-washing could drastically reduce childbed fever incidence, the term describes the tendency to dismiss or undervalue findings that conflict with accepted paradigms.

How it works

The Semmelweis reflex occurs when individuals encounter new information that conflicts with their pre-existing beliefs or accepted norms. Instead of objectively analyzing the evidence, individuals instinctively react by defending their current understanding. This reflexive rejection is often driven by discomfort associated with cognitive dissonance—the mental tension that arises from holding contradictory beliefs.

Examples

• In the 19th century, Semmelweis observed that hand-washing reduced mortality rates in maternity wards. Despite substantial evidence, his peers initially rejected his findings because it contradicted established medical practices.
• Climate change denial often illustrates this bias; despite overwhelming scientific evidence, individuals or groups obstinately refute new data that contradicts their pre-established beliefs about human impact on climate change.

Consequences

The Semmelweis reflex can lead to the perpetuation of outdated or incorrect information, hinder innovation, and prevent necessary changes or adaptations that could resolve problems or improve situations. In professional or academic contexts, this bias can delay the acceptance and application of beneficial discoveries or practices, adversely affecting progress and decision-making.

Counteracting

To counteract the Semmelweis reflex, individuals and organizations can cultivate an environment that encourages open-mindedness and critical thinking. It helps to foster a culture that values evidence-based reasoning and willingness to adapt beliefs in light of new, credible information. Training in recognizing cognitive biases can also aid individuals in questioning their instinctual reactions to new data.

Critiques

Critics argue that labeling rejection of new information as a Semmelweis reflex might oversimplify or misinterpret complex decision-making processes. Not all instances of rejected findings can be attributed to cognitive biases; often, new evidence may genuinely lack credibility or fail rigorous examination. Thus, discernment is essential to differentiate between healthy skepticism and unwarranted bias.

Fields of Impact

Also known as

Relevant Research

• On the merits and limitations of subpopulation analyses in observational research

  Greenland, S., & O’Rourke, K. (2001)

  Statistics in Medicine, 20(23), 3631-3641

• The dangers of deducing a causal relationship between brain biology and psychopathic behavior without considering the broader sociocultural context

  Lilienfeld, S. O., & Lynn, S. J. (2015)

  Psychological Inquiry, 26(3), 219-227