“The most necessary part of learning is unlearning our errors.” — Zeno
Question: Estimate the number of people you expect to die in the United States from the following causes over the course of the following year:
1. Homicides _____ or Suicides _____
2. Floods _____ or Tuberculosis _____
3. Tornadoes ____ or Asthma ______
If you’re like most people you will rate the number of deaths from homicides, floods and tornadoes as being higher than suicides, tuberculosis and asthma, but this is wrong. In fact, the numbers for the latter have been consistently higher than each of the former since records have been kept.
The reason so many people get the answer wrong is because homicides, floods and tornadoes are more vivid and easier to recall. Unfortunately, what people recall often bears little or no correlation to reality. The result is that people commonly expose themselves to greater risks for longer periods of time; or, alternatively, they worry about the wrongs things—such as being whisked away by a flood or a tornado.
If you wish to bolster your odds of surviving in the future, unlearning could be critical as the following story highlights.
In 1601, James Lancaster, an English sea captain, set sail from England to India. Overseeing a crew of 278 sailors on four separate ships, Lancaster conducted an experiment to evaluate the effectiveness of a treatment to prevent scurvy. He administered three tablespoons of lemon juice to the members of his ship and left the crews of the other three ships untreated—effectively creating a control group. Half-way through his journey, Lancaster’s experiment yielded startling evidence: none of the sailors on his ship had died of the disease but 110 of the sailors on the other ships—or 40 percent— had succumbed to the dreaded malady.With such clear and compelling evidence, one might have expected the British Navy to begin immediately administering lemon juice to sailors. It did not.
Nearly a century and a half later, in 1747, James Lind, a British Navy physician who was familiar with Lancaster’s work, carried out the first example of a truly controlled clinical nutrition study of the disease. He prescribed oranges and lemons to patients suffering from scurvy and found they were cured in a matter of days. Six years later, in 1753, Lind published his seminal work, “A Treatise of the Scurvy.”
Armed with this well-documented and scientifically-controlled information, one might again have expected the British Navy to make haste in prescribing regular doses of citrus fruits to all of its sailors. It did not. In fact, it took an additional 48 years for the disease to be eradicated.
Why did it take the British Navy almost two centuries to adopt a new, albeit simple, method for a treating a disease which could have spared the lives of untold numbers of its sailors? A variety of factors were at work but prominent officials and the sailors alike had different ideas for the best way to prevent scurvy and these erroneous ideas prevented them from being receptive to new knowledge. In short, before they could fully assimilate the new information they first had to unlearn their old knowledge.
It is easy to dismiss the scurvy case as an isolated example from history and chalked it up to poor scientific knowledge, the slow diffusion of new information, bureaucratic inertia or just plain stupidity. Unfortunately, the British Navy isn’t alone in its slowness to unlearn.
Consider the case of Australian physician Barry Marshall. In 1984, Marshall traveled to Brussels, Belgium to a prestigious conference of ulcer specialists to present his research suggesting ulcers were caused by bacteria. His presentation was greeted with laughter because the audience of ulcer experts judged the idea so preposterous.
A year later, Marshall (after drinking a vial of bacteria) returned with even more compelling evidence and this time was shouted down with a chorus of boos by the group. It took the American Medical Association a full decade before it accepted Marshall’s research and announced the vast majority ulcers were caused by bacteria and not by stomach acids, stress or spicy foods as leading ulcer experts had erroneously believed. In 2005, Marshall and his researcher partner, Dr. Robin Warren, were awarded the Nobel Prize in medicine.
This begs the obvious question: Why were hundreds of thousands of ulcer patients treated with unnecessary, costly and often ineffective treatment for more than 20 years? The answer is because many people, including highly educated medical specialists, have a difficult time unlearning old knowledge.
It would be reassuring to think that society has progressed much since 1984 and that it won’t repeat similar errors in the future but it would be wise to remain humble. To demonstrate, I’d like to share a mildly shocking insight with you: six times as many people died in their cars as a result of the terrorist attacks on September 11, 2001 as did in the planes that crashed into the World Trade Towers, the Pentagon and in the rural farm field in Pennsylvania—combined!
Impossible, you say? Not if you change your frame of reference and consider that since September 11, 2001 millions of Americans have decided to forego flying and instead chosen to drive to their destination. In this light, the numbers become more plausible because, statistically-speaking, driving is far more risky than flying. In fact, an estimated 1,710 (and counting) more Americans have died in automobile accidents than otherwise would have if only those travelers had chosen the safer method of travel—flying.
Alas, before people can accept that airplanes are more likely to get them safely to their destination, they first need to unlearn that driving is safer than flying. This isn’t an easy or even natural thing to do but, just as sucking on a lemon has saved and prolonged the lives of numerous sailors roaming the high seas, so too can unlearning prolong and, maybe even, save your life.
Homework Assignment: Research the following question: Which is the greater threat to a child’s safety: your neighbor’s swimming pool or the unlocked gun in his closet?
(Answer: By a factor of 50, it is the swimming pool. As a general rule, most of us are awful at assigning realistic levels of risk to everyday activities. To improve our odds of more safely navigating the future, remember, unlearning is a critical skill.)
