Cognitive Bias And The Art of Doctoring

While the full consequences of medical error cannot be measured, a cost estimate based on review of diagnostic error in US dermatology liability claims is a staggering $29 million.¹ A large part of diagnostic error can be attributed to cognitive bias, which can be defined as flawed decision making.² Defined in such a way, cognitive bias is a negative that needs to be corrected, although the last several decades of research in metacognition (thinking about thinking) shows that cognitive bias is entrenched in expert decision making.³ Another term used for cognitive bias is JDM bias, in which JDM stands for Judgment and Decision Making.⁴

Cognitive bias is inescapably useful to the fast, intuitive decision making that characterizes experts. Bias partially is a result of deliberate overlearning, particularly as it pertains to pattern recognition and the development of ingrained decision making.⁵ Although “bias” in general has a negative connotation, the positive aspects of “cognitive bias” can semantically fall under the more neutral terms “heuristic” or “rule of thumb.”³ In essence, a cognitive bias or heuristic can be not only a weakness but also a strength.

Heuristics in dermatology, on a basic level, include pattern analysis of morphology, color, pattern of distribution, body site affected, and secondary changes.² These heuristics are taught from the outset to early learners of dermatology, as they are an essential part of dermatologic diagnosis and visual recognition of skin disease. While these heuristics lead to greater expertise in dermatology, they also create pitfalls.² For example, the color heuristic is useful in dermatology but can lead to misdiagnosis when the background skin color influences color perception.²

We cannot wholly eliminate cognitive bias, because judicious use of heuristics is a hallmark of expert decision making. In other words, while the decision making of true experts involves heuristics, there is ever-present value in double-checking those decisions. This is metacognitive work, thinking about decision making and diagnosis, and for many experts it may be relatively rote. But to the extent that diagnostic error can be traced to cognitive bias, explicitly and consistently addressing heuristics and bias in diagnosis is beneficial.

Ultimately, whether we use the term cognitive bias or heuristic, evaluating decision making can more deliberately influence the cognitive and affective biases to which dermatologists might be vulnerable.^3,6 For example, all doctors are prey to the so-called “cognitive miser function,”⁶ which is the natural tendency of the brain to use the least amount of cognitive effort possible. This happens when a given diagnosis like psoriasis is recorded in a patient’s chart; the diagnosis may get carried forward over years without much reassessment of its accuracy, only to find out on performing a biopsy that the patient has psoriasiform lesions as a specific manifestation of sarcoidosis.2 Taking the time to consider particular mimics is useful.

Take Time to CARE

Simply thinking about decision making helps address cognitive bias. A proposed mnemonic is “CARE,” which in itself is a reminder to care for the patient.⁷ CARE stands for Communication, Assessing for biased decision making, Reconsidering differential diagnoses, and Enacting a plan. While the second step literally addresses cognitive bias, bias can also affect communication,⁸ decision making in general, and treatment plans. Patients are deserving of care in attending to each of these steps.

Familiarity with different types of biases that are both pragmatic and problematic can help dermatologists better recognize beneficial vs. detrimental use. Common biases,⁶ including availability bias, anchoring bias, confirmation bias, diagnosis momentum, premature closure, and unpacking failure, are listed in the Table, with salient examples of each as related to malignant melanoma, one of the diagnoses in dermatology that no one wants to miss. Additional ways to combat cognitive bias include self-care, continuous learning, and institutional practices that optimize health care delivery including forcing functions like the synoptic checklist included with the diagnosis of malignant melanoma. A vital prerequisite to many of these debiasing strategies is the initial awareness of bias.⁶

Increased recognition of cognitive bias in decision making⁶ will pave the way for dermatologists to more consciously promote patient safety. Taking the time to ask either, “What else could it be?” or “What might I be missing?” will help increase accuracy in dermatologic diagnosis. Going one step further, pinpointing the different biases (see Table) that contributed to any instance of medical error can further refine the ability to think.6 Decision making is a complex process but one step in preventing cognitive bias just takes thinking twice.

While diagnosis is important and deserves as much thought as possible, communication around that diagnosis is a necessary step for the best patient care. Most doctors are not actually trained in communication, and many doctors do not have the time to learn how to communicate better. Thankfully, good communication is predicated on the simple step of truly listening—even just asking, “How can I better listen to my patients?” Questions like this increase awareness of what the doctor is actually doing with the patient in the room. Some tools to promote a habit of listening is to ask patients open-ended questions, to repeat back to them information, and to ask patients to restate information they have been given. It is also helpful to listen for silence, not just words, and to pay attention to how body language is congruent (or not) with the words spoken aloud.⁸

Cognitive bias affects every decision made, whether it is in small decisions like how we greet a patient, or in larger decisions like how to treat an invasive melanoma. Refining decision-making and considering bias are essential to the art of doctoring.

1. Kornmehl H, Singh S, Adler BL, Wolf AE, Bochner DA, Armstrong AW. Characteristics of medical liability claims against dermatologists from 1991 through 2015. JAMA Dermatol 2018;154(2):160-166.

2. Lowenstein EJ, Sidlow R. Cognitive and visual diagnostic errors in dermatology: Part 1. Br J Dermatol 2018;179(6):1263-1269.

3. Kahneman D. Thinking, Fast and Slow. New York, NY: Farrar, Straus and Giroux; 2011.

4. Strough J, Karns TE, Schlosnagle L. Decision-making heuristics and biases across the life span. Ann NY Acad Sci 2011;1235:57-74.

5. Croskerry P, Petrie DA, Reilly JB, Tait G. Deciding about fast and slow decisions. Acad Med 2014;89(2):197-200.

6. Croskerry P. The Cognitive Autopsy: A Root Cause Analysis of Medical Decision Making. Oxford, England: Oxford University Press; 2020. doi: 10.1093/med/9780190088743.001.0001

7. Rush JL, Helms SE, Mostow EN. The CARE approach to reducing diagnostic errors. Int J Dermatol 2017;56(6):669-673.

8. Ko CJ. How to Improve Doctor-Patient Connection: Using Psychology to Optimize Healthcare Interactions. New York, NY: Routledge; 2021.