It’s hard to believe that hand washing was once considered controversial. In the 1840s, Ignaz Semmelweis discovered that when medical students performed autopsies in the morning and gave birth in the afternoon, maternal mortality was double the rate in the wards where midwives gave birth. As the midwives did not perform an autopsy, Semmelweis concluded that the particles from the autopsies contaminated mothers via the hands of medical students.

He instituted a hand washing routine that dramatically reduced maternal deaths. However, when he promoted the benefits of handwashing, he was widely derided because his conclusions conflicted with accepted dogma. Moreover, his theory tacitly blamed doctors for the deaths of their patients. Semmelweis died without his discovery being widely accepted.

In the years that followed, Florence Nightingale, Louis Pasteur, and Joseph Lister contributed to the growing understanding of germ theory and the disappearance of the belief in miasma as a cause of disease. Over the following decades, the benefits and practice of handwashing would gain popularity, especially in the medical community. However, it was not until the 1980s that the United States developed national standards of hygiene for hand washing. – 140 years after the initial discovery of Semmelweis.

Likewise, Louis Pasteur discovered that treating liquids such as milk with heat prevented bacterial contamination. Milk is nutritious because it contains all the essential amino acids and calcium. But precisely because it is a drink rich in nutrients, microbes love it as much as children. Poorly treated milk can carry fatal diseases such as tuberculosis, diphtheria and salmonella..

Pasteur made this discovery in the 1860s, but it was decades before pasteurized milk became available in major American cities. In the early 20th century, President Theodore Roosevelt’s Surgeon General released a voluminous report claiming that most child deaths were attributed to drinking contaminated milk. Chicago passed an ordinance requiring the pasteurization of milk in 1908, one of the first cities to do so.

The first state to pass a pasteurization law was Michigan in 1947. Federal government would not require all milk sold or distributed through interstate commerce to be pasteurized until 1987, more than 120 years after the discovery of Pasteur.

When did public awareness of climate change emerge? Most of the people I interviewed believe they first heard about climate change about 20 years ago. As this article makes clear, the scientific community has been thinking about climate change for more than a century. As a senator, President Joe Biden introduced legislation in 1986 to study climate change. In addition, Eunice Foote demonstrated the greenhouse effect, the concept behind climate change, in 1856.

Why do scientific findings meet resistance and often take decades or more to gain wide acceptance? There is no single answer to this question, but there are several illuminating ideas, both about the method and the process of rejecting new scientific information.

Psychologist Matthew Hornsey points out that, “Beliefs are hard to change, because people don’t act like scientists, evaluating evidence in an unbiased manner. When someone wants to believe something, then they act more like lawyers trying to pursue what they already want to be true.

This point of view is supported by Professor Jonathan Haidt of the University of Virginia, author of “The Righteous Mind” which emphasizes (as did the Nobel laureate Daniel Kahneman) that humans are not rational. Most of us, most of the time, make decisions based on emotion or intuition, rather than reason.

Using brain scans, Haidt found that when research subjects were asked moral questions, their pattern of brain activity showed that they were coming to conclusions quickly and provided reasons after the fact that supported the conclusion they were making. had arrived.

This process has been referred to as confirmation bias.. When people primarily seek information that confirms what they already believe, they engage in confirmation bias. Its close cousin is reasoned reasoning, a type of confirmation bias in which information conforming to existing beliefs is deemed more credible and conflicting information is rejected or ignored.

One of the reasons people engage in reasoned reasoning is to maintain congruence with the belief structure of the group they are aligned with. – typically religious or political. Therefore, evidence contrary to the belief of his identity group is threatening and dismissed.

It is a wonder, given the strength of emotions, resistance to change, and the power of group identity that scientific discoveries are ever adopted. However, the stew awareness of influences that impact belief in science has the potential to make everyone more thoughtful and deliberative, the first step is to recognize that rationality is a goal, not a given. .

Claire Noble can be found online at Claire Noble Writer on Facebook.