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Question

Difficulty: MediumHuman Factors and Cognitive Biases

A 62-year-old man with a well-documented history of severe alcohol use disorder is brought to the emergency department by EMS after being found sleeping on a park bench. The triage notes state, "Intoxicated, smells of alcohol, uncooperative." The assessing physician evaluates the patient, noting lethargy, slurred speech, and ataxia, and establishes a working diagnosis of acute alcohol intoxication. A non-contrast head CT is obtained due to a small scalp abrasion. The scan reveals a small subdural hematoma. The physician briefly views the imaging and documents, "likely chronic subdural hematoma, incidental and non-contributory to current acute intoxication state," without comparing it to any prior neuroimaging. The patient is placed in the observation unit to metabolize the alcohol but becomes unresponsive three hours later due to uncal herniation. The physician's specific act of rationalizing the objective CT scan findings as 'incidental' in order to maintain the preconceived diagnosis of acute alcohol intoxication best illustrates which of the following cognitive errors?

  1. A
    Anchoring bias
  2. B
    Availability heuristic
  3. C
    Framing effect
  4. Confirmation biasAnswer
  5. E
    Premature closure

Answer

Confirmation bias
The correct answer is confirmation bias. Confirmation bias is a cognitive error where a physician selectively interprets, favors, or ignores new information to validate a preconceived working diagnosis. In this scenario, the physician has established a diagnosis of acute alcohol intoxication. When presented with objective data that should prompt a broader differential (a subdural hematoma on a head CT), the physician rationalizes it as 'chronic' and 'incidental' without proper verification. By bending the new evidence to fit the existing theory rather than adjusting the theory to fit the evidence, the physician demonstrates confirmation bias.

Step-by-Step Solution

1
Identify the primary cognitive error described in the clinical vignette.
The physician rationalizes an abnormal head CT finding (subdural hematoma) as 'incidental' to maintain the initial diagnosis of alcohol intoxication.
Understanding the specific point of failure in the diagnostic process is necessary to classify the cognitive bias accurately.
2
Differentiate between anchoring bias and confirmation bias based on the physician's actions.
While anchoring involves fixating on the initial presentation (intoxication), confirmation bias specifically describes the subsequent mishandling of new evidence (rationalizing the CT scan) to fit that initial anchor.
Distinguishing between these closely related biases is required to select the single best answer.

Key Concept

Confirmation bias occurs when a clinician selectively searches for, interprets, or ignores new objective information in a way that confirms their preexisting diagnostic hypothesis.
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Topics

Human Factors and Cognitive Biases

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