From experience, most people mention critical thinking in two cases. Either we speak of critical thinking to explain why homeopaths, psychics and other charlatans are mistaken (this is the art of zététique). Or we talk about critical thinking in the context of scientific research. Indeed, researchers must display rationalism explicitly in their work.
In truth, critical thinking is an essential skill for almost all professions. Whether you are a manager or an engineer, knowing how to combat cognitive bias is a decisive asset that greatly improves your decision-making.
The only thing better than a good example to illustrate my point ? Two good examples (of course). And that is why I will present two professions where critical thinking is life-saving: physicians and traders.
Medical students: poorly prepared decision-making machines
Jérôme Groopman has compiled research on medical decision-making in his incredible book "How doctors think". He presents dozens of cases of misdiagnosed patients who have suffered a lot. Diagnostic errors are said to be the cause of 80% of medical errors, and 15% of medical treatments are incorrect. In many cases, diagnostic errors are due to a lack of critical thinking.
Let's take the true story of the patient named Anne Dodge, for example. She suffered for fifteen years from diarrhoea and vomiting. These fifteen years were a martyr for her, and several dozen physicians had come to the same diagnosis about her: Anne Dodge suffered from bulimia. But her life changed when an extraordinary physician - Dr. Myron Falchuk - diagnosed him with a gluten allergy. Anne Dodge ate 3000Kcal per day, mainly pasta, to fight her malnutrition. A few months after her (good) diagnosis, she had regained 15Kg, simply by not eating gluten anymore.
Dr. Myron Falchuk is a very good physician, and it was this person who made Groopman want to write his book.
Lack of critical thinking among physicians
Physicians are heroes who must face all critical biases on a daily basis to treat their patients. Unfortunately they are handicapped in their struggle:
- they are never explicitly trained in critical thinking during their studies;
- they are very strongly influenced by their prejudices when meeting a patient to make their diagnosis (an obese or alcoholic patient is not listened to in the same way as an athlete);
- the vast majority of patients (general practitioners and emergency physicians) have nothing serious, which biases their subsequent choices;
- the astronomical volume of patients they treat may over time reduce their alertness due to repetition.
There are a multitude of strategies that good physicians all apply. Before meeting with a patient, a physician may do a little mental preparation to remember several key principles in his or her diagnosis.
- remember that each patient is unique. Try to ignore the 400,000 previous patients he has seen in his life and devote all his attention to the new person.
- Prepare for the worst. Even if such symptoms most probably correspond to a particular disease, it is essential to also take into account the unlikely cases, which can be much worse. Good physicians explain that before making their final diagnosis, they ask themselves "which is the worst disease that could correspond to these symptoms? "Then they re-evaluate this possibility before deciding.
- make decisions in low-pressure situations, when possible. Daniel Kahneman has shown it: a decision made calmly is often more accurate than a decision made on the spot.
Lucidity: essential for physicians and computer scientists alike
But above all, good physicians have a profile that is the same as a good computer scientist.They do not give up.
I have two or three friends whom I consider to be excellent coders. What fascinates me most about them is their determination. A normal coder (like me), tries to understand a bug only for a while. Then, if he doesn't know where the bug comes from, he bypasses the bug (with the certainty that it will come back later, striking harder). With physicians, it's exactly the same. Dr. Alter, for example, had conducted several extensive examinations following an inexplicable vertebral fracture found while examining a child. After several unsuccessful analyses, these colleagues tried to reason with him by pronouncing the sentence that characterizes average physicians (or computer scientists):
“sometimes things happen that can't be explained. That's the way it is.". This sentence shows a lack of lucidity. In this case, Dr. Alter was right to be relentless: the child was later diagnosed with a leukaemia - still in time to be cured.
Traders are firefighters like any other
Traders also practice a profession where critical thinking is essential.
One of the principles of critical thinking that I particularly like is the "fire station" effect. In a fire station, firefighters spend a lot of time with each other, cut off from the world. So much so that by communicating only with each other, they can end up sharing the same ideas, even if they are strange and anyone who does not belong to the barracks would immediately realize it. Nassim Nicholas Taleb, a very influential intellectual in economics, explains that traders are victims of this bias, which indicates a lack of critical thinking.
Indeed, traders work in a very specific field, and the profession is cruelly lacking in critical thinking. This is how the "Long-Term Capital Management", an investment fund composed of superstars of the field (including two "Nobel prizes" of the economy) lost 1.8 billion dollars after disastrous decisions.
Taleb's analysis
Taleb is a skeptic and a vehement rationalist.
According to him, the stock market has been operating in a fairly similar way since the beginning of the 20th century: relatively stable growth, but about every 10 years a major crisis occurs. What he has frequently found in the financial world is that traders will present things in the least critical way possible. "Some crises are not predictable, that's life. I did a good job most of the time, but you can't see everything coming. But thinking like that is a mistake. If a trader, in the end, has lost more than he has earned over the course of his career, then he has done a bad job.
According to Taleb, this is the result of a multitude of reasoning errors :
- the freezing effect: when you have made an investment, and you start losing money, you prefer to get bogged down in the hope that things will get better rather than acknowledge your mistake;
- the fire station effect: a profession is the victim of its own culture;
- a lack of lucidity: if something is too good to be true, then it is not true;
- a profound misunderstanding of statistics and probabilities (the most forgivable mistake in a sense, but which is no less dramatic).
Do traders play darts?
Daniel Kahneman once conducted a study at a traders' firm that hired him to answer a question: how to determine which traders are the best?
He studied the traders' rankings (by gain) in the company for each year, and found that these rankings were completely uncorrelated to each other. In other words, a bad trader in the year n could become an excellent trader in the year n+1.
His conclusion was irrevocable: the results of these traders were purely luck-based. Like the results of a coin-tossing tournament : skill had nothing to do with them. Therefore, these traders could not be ranked.
How critical thinking helps us to progress professionally
To be good in a profession, initial training is not enough.
And I think that critical thinking allows you to provide the necessary perspective on your profession: who is good at my profession? What skills does he have that I absolutely must develop (such as perseverance and mental preparation for physicians)? And more importantly : what are the mistakes in my field that most people make (and therefore that no one will come to report me since no one realizes it) ?
Whatever the profession, in fact, I would recommend that anyone spend a lot of time reading the basic books on this profession, because it is the best way to understand the world in depth (so physicians: read "How doctors think", and traders, read Nassim Nicholas Taleb 😉).