Why Do So Many Claim Expertise in Reading Scientific Literature?

‘Last October an op-ed piece appeared in the  New York Times titled “The quest for scientific certainty is futile.” The author is Adam Mastroianni, described as “an experimental psychologist and the author of the science blog ‘Experiment.’”

That provocative title certainly caught our attention. We always thought that at least some things in science are fairly certain. In the health field, for instance, there is certainty that high blood pressure and high blood levels of low-density lipoprotein (“bad cholesterol”) increase one’s risk for heart attacks; that cigarette smoking causes lung cancer; and that vaccines reduce the risk of acquiring and/or getting very sick from a range of infectious diseases.

In physics, we don’t see anyone expressing uncertainty about the basic laws of thermodynamics, general relativity, or even the uncertainty principle itself. Chemists, evolutionary biologists, and astronomers all seem to have principles, laws, theories, and equations they consider fundamental and certain. The quest for certainty in science is far from futile because scientists reach firm conclusions on a regular basis. Rather, the quest for certainty is an ongoing process. 

The Data for Dental Flossing Are Weak

What seems to have set Dr. Mastroianni off is a 2019  Cochrane review paper that concluded that although dental flossing may reduce gingivitis and plaque, the quality of the evidence supporting those assertions is poor and more evidence is needed. “I thought,” Mastroianni writes, “that I was born into the age of science and reason. But what my trip down the flossing rabbit hole taught me is that this is nowhere nearly as true as I hoped it to be…the more I learn about science, the more I discover basic mysteries that I assumed were solved long ago. Perhaps we’ve exited the Dark Ages, but our own age seems rather dim.”

To buttress that nihilistic conclusion, Mastroianni piles on other examples of what he believes to be scientific uncertainty in addition to the benefits of flossing. These include:

• How antidepressants work. Here he cites a recent review that concluded that antidepressants do not in fact work by increasing levels of the brain neurotransmitter serotonin. From this he concludes “Maybe that’s why antidepressants don’t seem to work that well.”
• Whether sunscreen is effective in reducing skin cancer risk. He claims that a 2018 meta-analysis he dug up “could not conclude that this is true.”
• The recent withdrawal by the U.S. Food and Drug Administration (FDA) of phenylephrine, an ingredient in popular over-the-counter cold and allergy medications, because it is no better than placebo.
• Dark matter and dark energy, which scientists say dominate the universe “but they don’t really know what it is.”
• The utility of face masks for reducing acquisition and transmission of aerosolized virus particles. Once again, Mastroianni cites a  Cochrane report that some people think failed to find a benefit for face masks.

Uncertainty is Fundamental to Science

We recognize that uncertainty is an integral part of what science is all about. Even when we consider things we know with certainty there is always more to learn. The problem with Mastroianni’s analysis, however, is that it fails to put what he thinks is uncertain in context or to explain how scientists themselves go about determining that they need to conduct more studies to get better answers to lingering questions.

Let’s start with flossing. The Cochrane review relied on 15 studies that have been published that examined whether flossing plus brushing reduces gingivitis more than brushing alone. As noted above, a small effect was in fact found for flossing. But as noted in an National Institutes of Health (NIH) piece called  “Don’t toss the floss,” such studies are very difficult to conduct because they rely on people accurately reporting how much they floss or don’t floss. Studies that rely on this kind of self-report are prone to errors that wash out the effect of an intervention under scrutiny. Also, the studies were all short term, so it is possible that flossing for years instead of months may make a bigger difference for oral health. The NIH also noted that many dentists are sure that flossing is effective and that it has no known risks or adverse side effects. One would conclude from all of this that although scientific studies don’t show that flossing is a slam dunk, there is ample evidence to suggest it probably helps and cannot hurt. Uncertain as this conclusion may be, it surely doesn’t seem to warrant being the basis of a general dismissal of the certainty of all of science.

If we look at each of Mastroianni’s other assertions, we see similar problems with his approach and logic. With respect to the antidepressant claim, almost no expert in the field has believed that they work by simply increasing levels of serotonin in the brain for at least the last three decades. The review that came to that conclusion was really setting up the proverbial straw man to knock down. In fact, all marketed antidepressants have passed the test of relieving depression symptoms more than placebo in randomized controlled trials. They don’t work for all people who are suffering from depression, but they work very well for many. Mastroianni’s conclusion here is clearly misleading and to the extent it dissuades people from considering evidence-based options to treat depression, irresponsible. 

The sunscreen example he uses is more egregious. The review paper he refers to was actually set up to determine if sunscreen increases the risk for acquiring melanoma, the most serious form of skin cancer. It found that it does not increase the risk but says absolutely nothing about whether sunscreen decreases the risk for skin cancer. Other studies have indeed shown a protective effect of sunscreen against the three major types of skin cancer. The bottom line, according to a bevy of experts, is to use sunscreen if you are out in the sun. And why does Mastroianni consider the withdrawal of phenylephrine a blow to science? The main problem with this that we see is that it took too long for the FDA to act on certain evidence that phenylephrine is ineffective to order it off the market. Mastroianni doesn’t mention that solid evidence led to that action or that withdrawals of already approved medications are very uncommon.

Nor do we understand his point about uncertainty surrounding the exact nature of dark energy and dark matter. Dark matter is postulated by astrophysicists because it is necessary to explain observed rotations of galaxies, and dark energy is needed to explain the observed expansion of the universe. Both are based on decades of careful research and continue to be the subject of intense investigation that hopefully will yield important discoveries. Much about the cosmos is well understood by scientists, so why is Mastroianni so bothered by things that are yet to be elucidated?

Finally, his jab at face masks is plainly wrong. The Cochrane report that fueled politicized skepticism of face masks is  riddled with errors and has been widely criticized by experts.  Better analyses of the data on face masks show that they work to cut down on the acquisition and transmission of viruses like the one that causes Covid-19. Mastroianni engages in what we call “cherry picking” by selecting just one publication to support his skepticism of face mask effectiveness rather than considering the weight of publications and commentary that provide a much more informed picture.

There are at least two conclusions we can make by reviewing the Mastroianni piece in the New York Times. First, there is a lot of certainty in science. Looking across his six examples of alleged uncertainty, what we actually see is some very firm evidence. Second, that there are many things we don’t know about these six topics and that is why scientists continue to conduct experiments and observations. There will never come a time when we know everything about the natural world around us, which is why science will be needed in perpetuity.

Uncertainty, then, is part of the natural progression of science. Rather than rail against science and scientists for not knowing everything, we need to be curious about this unfolding of knowledge. How will better studies show us optimal ways to protect oral health? What is the mechanism of action behind antidepressants? What are the fundamental particles and forces that constitute dark energy and dark matter? Yes, we are uncertain about these things, but that hardly puts us back in the dark ages. And as scientists unravel these mysteries, we better keep on flossing, applying sunscreen, and wearing face masks during pandemics.