COGNITIVE BIASES AND THE DOCTOR-DETECTIVE DIAGNOSIS

March 07, 2019 / Ashley Romanchuk

A cognitive bias is an error in thinking that effects judgements, decisions and conclusions of an individual. In medicine, it is important for a Doctor to be aware of these in making the appropriate objective diagnosis and to make sure important information is not overlooked via the differential diagnosis. Cognitive biases are basically limitations in how our brain and power of logical and analytical reasoning and deduction can be blocked, typically these are called ‘heuristics’ in Psychology and usually deal with a variety of mental short cuts that we learn to naturally make to come to a conclusion on how we perceive a person, place or event. Having an understanding of these biases and then spending time (as the Doctor) to see where they might come into play in the Doctor-Patient relationship is an important facet of practice.

There are many, many, many biases available and typically we know some of the basic ones such as Stereotyping: expecting the person to have certain qualities without having real information of the person. Most doctors try to make sure they do not make these assumptions however it is easy, especially if a patient walks in that is not of typical norm to the other patients. In the land of Bias, we as doctors must always check ourselves. I would argue that one of the most important aspects to being a Doctor is to have HUMILITY to the human race and to ourselves. Making a preconceived judgement or allocating a person or event into a category in the mind is very natural and part of how we have learned to survive, to make sure we are not in danger at the most basic and primitive level however Doctor, you are not the one that is struggling to survive, your patient is and having the humility to see that person as a wonderful being of this land, a living person, and to see them through eyes of love firstly (not immediate judgement) is critical in making sure a stereotypical bias is not somewhere inherent in your perception of this person and their story. Alongside a stereotype bias, I am going to throw in the bias of Selective Perception which is just as critical and very similar. Doctor: you can not allow your expectations to influence your perception of the outside event. To further end just this first paragraph, just so you have the definition itself, a Blind Spot Bias is failing to recognize your own cognitive biases and is a bias in itself :). I would say then that spending time recognizing where we might have our biases as Doctors is a critical part of our job.

These are typical, we know these ones as Doctors. Let’s get into the other ones that are easy to understand but very much come into play and create issues in Diagnostics (and thus, not so easy to necessarily bypass). The first is Anchoring Bias: the over-reliance on the first piece of information received. In this Google Age, this is difficult. How many patients come in these days and firstly say, “I think I have …” then give the plethora of information (history and symptoms) for the Doctor to build on. This is TROUBLE. Super trouble. Because immediately, and very very naturally dear Doctor-detective, you have already been skewed by the first piece of information and I will tell you why…In meeting your patient for the first few minutes, you have already cleared your brain to pick up fresh information and this freshness will last for the first few minutes. Remember when you used to study? How long was it? Probably under the first 10 minutes that your brain drastically took up information and the recall was the strongest. This is the same in the patient-visit and this is why this is called an anchoring bias. It is very very strong. Beware. Alongside this very pulling bias, I would put the bias of the Bandwagon Effect which is the tendency and the heightened probability of one person adopting a belief increasing based on the number of people that also hold that belief. If a patient comes into your care presenting to you many other doctors previous diagnostics (and obviously they have not worked), you are being faced with both anchoring bias and the bandwagon effect. Humility again is important. Take a humble approach, be confident in yourself. Know that you both know nothing (have a clear slate on your perception of this patient and their story) and know everything (you ARE a Doctor). Find the balance here.

Next let’s go deeper into the interview where we will see some more biases come out as the Doctor gets to decipher a whole load of information, categorize it and decide what is pertinent and what is not. This is the art of medicine, anyone (not really, but you know what I mean) can study pathology and treatment. Deciphering information quickly and correctly is something that takes a lot of practice. Firstly, let’s start with Overconfidence by the Doctor. Lacking humility in our abilities can cause us to take greater risks, especially those that deem themselves “experts”, this can easily also lead to a plethora of many other biases too as if you are an expert, you will already have the anchoring bias inherent in your practice. Have you heard the saying ‘when you are a hammer, everything is a nail’? This is pertinent here. Again…Humility, humility, humility. I keep saying it, clear your mind, clear your ego. Begin with humility. The definition of humility is to have a modest view of ones own importance. This means to put yourself below the other person, to serve them, for their own highest well being (not yours ;) ). Paradoxically, I am going to mention what is termed as the Dunning-Kreuger Effect: the theme that there is a tendency for unskilled individuals to overestimate their abilities, while the skilled individuals underestimate their abilities. Incompetence prevents one from recognizing incompetence. As skill level rises, one becomes more aware of his/her own incompetence. There is a balance here once again, know your worth and be humble ;).

After this, I am going to argue that as a Doctor, you must find the line between the Anchoring bias, Saliencey: our tendency to focus on the most easily recognizable features of a person or concept and Recency: The tendency to weight the latest information more heavily than older data. Obviously Doctors know this takes practice, there is even a cognitive bias that is proven that too much information can skew ourselves from the facts of the matter. This is called the Information Bias. And this is where medicine becomes an art, Doctors must know the questions to ask, when to ask them and how to ask them and then how to collect and divide all of the information. Furthermore, we must ask ourselves if there is a tendency to seek information when it does not affect action…More information is not always better as it has been shown that with less information, people can often make more accurate decisions. So a quick summary of what I have just said is let’s realize that more information is not always a good thing. The first and last pieces of information a patient gives have been shown to hold a lot more weight in the mind than the rest of the story and there is a typicalness for even the Doctor to pick out the typical red flags or prototypical clues which can lead to bias in Diagnosis.

So now, let’s get into the Diagnosis. Beyond all these biases, we still have more! We have been trained as Doctors to extract certain pieces of information (again go re-read what the saliency bias is) in doing this, we need to be careful and aware also of the bias of Clustering Illusion: Tendency to see patterns (or not see patterns) in random events. I am going to put this out there at this time, bloating, fatigue and feeling full easily are often some of the only signs and symptoms of some major cancers such as the lympathic cancers. Be wary. A Confirmation Bias is the tendency to listen to information that confirms our preconceptions and once we have formulated a theory, we pay more attention to items that support it and ignore evidence that disproves it. Somewhere in your interview, you started to align the information towards a specific diagnosis. Be careful that you are now not just collecting the information from then on to support this. This leads us into two more biases to recognize: the Choice Supportive Bias which is the fact that when you choose something (ie. a diagnosis) you tend to feel positive about it even if there is flaws. The Ostrich Effect is the decision to ignore dangerous or negative information (also comes full circle with the clustering illusion bias). Holy moly! There is a lot to think about and the psyche is so interesting! This is by no means a complete list, there are so many more biases that cloud our vision (often called “The Veil of Perception”). Here are some more interesting ones:

Action-Oriented Bias: we as Doctor feel pressure to take action, to know the diagnosis, to take course in treatment. This is our job. Remember when we were taught in school to say “I don’t know” and how this can be a very powerful tool. Don’t let your ego get in the way of somebody else's health.

Self-Interest Bias: Similar to above, and similar to the bias of Overconfidence. Doctors are somewhat competitive businesses themselves in a competitive market.

Publication Bias: Very important for the Doctors that put a lot of worth on EBM! Scientific Journals and Publishers publish studies with positive results and rarely with negative results.

Recency Bias: The tendency to weight recent information or history more than something that happened a long time ago.

Lastly, I am going to end this all (I could go on for very long time) with what is termed the Semmelweiss Reflex: the tendency to reject new evidence that contradicts an established paradigm/diagnosis/treatment. the tendency to reject new evidence that contradicts an established paradigm. Each patient return-visit must have a clean platform and Doctor, be humble enough to recognize you might have not been right in your diagnosis or that your treatment is not working well, and be prepared to start over. Another fresh start.

JUNE 1, 2016

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