Matt Ridley schreibt im Wall Street Journal: The reason that science progresses despite confirmation bias is partly that it makes testable predictions, but even more that it prevents monopoly. By dispersing its incentives among many different centers, it lets scientists check each other’s prejudices. When a discipline defers to a single authority and demands adherence to a set of beliefs, then it becomes a cult.
A recent example is the case of malaria and climate. In the early days of global-warming research, scientists argued that warming would worsen malaria by increasing the range of mosquitoes. “Malaria and dengue fever are two of the mosquito-borne diseases most likely to spread dramatically as global temperatures head upward,” said the Harvard Medical School’s Paul Epstein in Scientific American in 2000, in a warning typical of many.
Carried away by confirmation bias, scientists modeled the future worsening of malaria, and the Intergovernmental Panel on Climate Change accepted this as a given. When Paul Reiter, an expert on insect-borne diseases at the Pasteur Institute, begged to differ—pointing out that malaria’s range was shrinking and was limited by factors other than temperature—he had an uphill struggle. “After much effort and many fruitless discussions,” he said, “I…resigned from the IPCC project [but] found that my name was still listed. I requested its removal, but was told it would remain because ‘I had contributed.’ It was only after strong insistence that I succeeded in having it removed.”
Yet Dr. Reiter has now been vindicated. In a recent paper, Peter Gething of Oxford University and his colleagues concluded that widespread claims that rising mean temperatures had already worsened malaria mortality were “largely at odds with observed decreasing global trends” and that proposed future effects of rising temperatures are “up to two orders of magnitude smaller than those that can be achieved by the effective scale-up of key control measures.”
The IPCC, in other words, learned the hard way the value of letting mavericks and gadflies challenge confirmation bias.
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