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Dunning-Kruger Effect

Scientific Expertise vs. the Dunning-Kruger Effect

A conversation with Nobel Prize winner Adam Riess.

Key points

  • The scientific method teaches us to test hypotheses and form beliefs based on evidence and repeated observations.
  • In the internet era, many believe that their own viewpoints are just as valid or accurate as that of experts.
  • Although scientific experts often second-guess themselves, most of us are prone to the overconfidence of the Dunning-Kruger effect.
NASA/public domain
Type Ia supernova
Source: NASA/public domain

In 2011, Adam Riess—my one-time freshman roommate at MIT and now Bloomberg Distinguished Professor and Thomas J. Barber Professor of Space Studies at the Krieger School of Arts and Sciences at Johns Hopkins University—won the Nobel Prize in Physics for his postdoctoral work using the Hubble Space Telescope.

While looking at light emitted from Type Ia supernovae in the distant universe, he and his colleagues observed that contrary to the prevailing expectation that the universe’s expansion that began with the Big Bang was slowing down, it was actually speeding up. Riess says that when they first saw the data, they assumed it had to be a mistake since it didn’t conform with the existing model at the time. But with repeated analyses and observations that were confirmed by another team of researchers doing similar contemporaneous work at the Lawrence Berkeley National Laboratory, they eventually realized that the data were right and the model itself had to be revised. It’s now an accepted fact of science that the universe’s expansion is accelerating, most likely due to a force called “dark energy,” the nature of which remains something of a mystery that Riess and other astrophysicists are still trying to unravel.

A few years ago, when I was catching up with him, we got to talking about his discovery and the unexpected way that it changed his life. In this follow-up conversation, we talk more about science, scientific expertise, and the Dunning-Kruger Effect.

Joe Pierre: When I listened to an interview you did for the TED Radio Hour back in 2013, I was impressed with your account of how you didn’t really believe—or want to believe—what you first “observed” through the Hubble Space Telescope. But rather than trying to discard the observation or try to fit it to existing theory as we do when we succumb to confirmation bias or motivated reasoning, you repeated your observations and did the opposite—you reshaped the theory to fit the data. This reminds me of something that Richard Feynman said about science—“It doesn’t matter how beautiful your theory is, it doesn’t matter how smart you are… If it doesn’t agree with experiment, it’s wrong.” Can you say more about how you approached your research and how you maintain that attitude in your work or even in your daily life?

Adam Riess: I have always had a strong belief in the scientific method that I was taught—you do an experiment to test a hypothesis and if the data doesn’t fit (and you can confirm the data), you must revise the hypothesis. This is what makes science different and more capable of explaining the natural world than religion or politics where you hold to your beliefs. Unfortunately, this can drive my wife nuts as I like to test a lot of hypotheses around the home that I should probably take on faith!

JP: Around the time you won the Nobel Prize, a friend of mine who had an undergraduate degree in engineering had his own thoughts about the universe. He thought they were valuable insights and he wanted me to share them with you. In talking with you through the years, I understand that you get contacted by people all the time who believe they have something meaningful to contribute but whose understanding of basic physics is often lacking. Can you tell us more about these interactions?

AR: I get about a half a dozen “proposals” per month from people who have no background, probably not even a course in college physics, trying to explain the mysteries of the universe to me. These always seem to be gibberish as far as I can tell, sort of a word salad of terms and equations but not following logic.

The people who send these seem to have a deep desire to be able to say that they’ve pulled the proverbial sword from the stone of contemporary physics. They want me to validate their findings. In many cases, they want me to propose them for a Nobel Prize. It’s really an astonishing phenomenon. In all of these cases, they do not know enough to know they are not making sense. Also, these folks are always alone in their work—they’re not collaborating with anyone—and they’re all men.

These interactions can be either fun or frustrating depending on how seriously the person takes their theory. I’m always happy to explain the science and listen to a question—but when someone’s theory isn’t a question but an insistence on what’s right and it’s not based on an understanding of the science, the interactions aren’t productive.

The thing that always amazes me isn't the outlandishness of their theories, but that they're always so sure that they're true. The scientists I know are always worried about whether their understanding is right. These guys aren’t worried about that at all.

JP: In the era of everyone “doing their own research” on the internet, what do you think these interactions have to say—other than being a perfect illustration of the Dunning-Kruger effect—about what Michael Polanyi described as “The Republic of Science”? One way of looking at it seems to support the idea that in the eyes of the public, expertise is dead because the internet has democratized opinion to the point of everyone believing their own viewpoint is just as valid or accurate as that of experts. To what extent do you see it like that—and as a kind of annoyance?

AR: I understand that everyone wants to jump into the deep end of the pool and have a go at the mysteries in science, but it takes a lot of work and study to understand the ideas that have been tried and failed and why they failed. I would ask anyone who’s rational to think of something about which they have acquired deep knowledge or training. Would it make sense for someone who knows little about that subject to tackle the hardest problems in that area? If you needed brain surgery, would you trust the brain surgeon who has maybe done a tricky procedure hundreds of times, or say your neighbor who has a big heart and thinks he/she knows another procedure to try?

I saw a recent cartoon in The New Yorker by Will McPhail that put this in perspective. A guy on a commercial airline flight who’s standing up and facing the other passengers says, “These smug pilots have lost touch with regular passengers like us. Who thinks I should fly the plane?” And a lot of them are raising their hands.

I also think there’s an element of “shooting the messenger” to modern science. Who wants to hear that the planet is warming, that the latest COVID variant is extra deadly or that sort of thing? When you don’t understand the science behind those claims, it’s a very human response to say that “the emperor—that is, scientists and the experts—have no clothes.”

JP: Another way of looking at this is that expertise might be dead due to a failing of science education that those of us within “The Republic of Science” should own. In other words, if the state of people’s scientific knowledge wasn’t plagued by a failure in understanding some basic elements of math or physics or biology or what have you, then maybe they’d be less vulnerable to the false confidence of the Dunning-Kruger effect. But that's on people like us who teach within scientific disciplines. Doesn’t this mean that we need to remedy the situation by either revamping K-12 education for children from the ground up or by letting adults who think they know better “in the door” and giving them a “seat at the table” so that science would seem less ivory tower and scientific experts would seem more trustworthy? I’m curious what you think about this premise.

I think we need to focus on explaining the methods of science for cases everyone can understand so that they can believe science when the details are beyond their grasp. This is something I try to put into practice when I teach undergrad non-science majors. Science is an incredibly powerful and logical method of finding truth that has driven essentially all of the technology and know-how we have today. It has a great track record and we need to explain that in a way that’s inspiring.

JP: I don’t know if you’re familiar with it, but there’s something called “Nobel disease” that describes how some Nobel Prize winners have gone on in their careers to embrace fringe theories and spread dangerous misinformation, especially outside their areas of expertise. It's a great example of how no one is really immune to the Dunning-Kruger effect. Do you have any unusual theories outside of astrophysics that you want to leave readers with?

AR: Well, I do think all Twinkies were made in the 1980s with enough preservatives so that those same ones are still sold today. Did you ever see a moldy Twinkie? No one has.

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