Before the 20th century, stomach ulcer was not a respectable disease. As stress was the believed cause, Europe and America had health spas and quack treatments to cure ulcers.
Eventually doctors realized they could see the ulcers with X-ray machines, but these machines were in big cities like New York and London. So, doctors in those cities started identifying ulcers in urban businessmen who probably smoked a lot of cigarettes and had a high-pressure lifestyle. Stress again – it all fit.
In 1981, Doctors Warren and Marshall in Australia noticed that biopsies of ulcer and stomach cancer patients seemed to have bacteria called Helicobacter. Everybody who got stomach cancer developed it on a background of gastritis. And, when there was no Helicobacter, there was no gastritis. Despite initial apathy, they went on to prove that ulcers were caused by Helicobacter. And, they won the Nobel prize in 2004.
What makes this story is amazing is that there were other doctors who’d observed this before them. In every case, they dismissed the evidence as it went against the commonly held belief. In effect, Doctors Warren and Marshall won the Nobel prize for being open to evidence that contradicted their beliefs.
To gastroenterologists, the concept of a germ causing ulcers was like saying that the Earth is flat. After that I realized my paper was going to have difficulty being accepted. You think, “It’s science; it’s got to be accepted.” But it’s not an absolute given. The idea was too weird. – Dr Barry Marshall
Image Source: Discover Magazine, Ian Regnard
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Source and thanks to: Persuadable by Al Pitampalli, Discovery Magazine’s interview with Dr Marshall
A Learning a Day 
As always, thanks for sharing. Sounds like a great example of what Daniel Khaneman refers to as “theory-induced blindness” in his book Thinking, Fast and Slow (which I know you have reviewed before).
Keep up the great work!
Yup – that would be right. Thanks for sharing, Jake!
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http://www.ALearningaDay.com – *Never failure, only learning and never older, only better..*
The relevant quote for this is, “science advances one funeral at a time.”
Thomas Kuhn’s classic, “The Structure of Scientific Revolutions” deals with this topic in great detail. He uses the example of ether to great extent, talking about how even through many experiments that assumed the existence of ether didn’t pan out, people still refused to accept it didn’t exist.
Ha. Nice thought. Thank you for sharing! :)