MCAT® ExamCritical Analysis and Reasoning SkillsMedium
A physician is evaluating a patient presenting with symptoms that could indicate either a common infection or a rare autoimmune disorder. Given the patient's demographic information, the physician initially leans towards the common infection, despite some atypical findings. This initial diagnostic inclination, based on the prevalence of the conditions, best exemplifies which cognitive bias?
- AHindsight Bias
- BAnchoring Bias
- CConfirmation Bias
- DBase Rate Fallacy
Show answer & explanationAnswer & explanation
Correct answer: D. Base Rate Fallacy
The physician is overlooking specific atypical findings in favor of the statistical likelihood of a common infection, which is a classic symptom of the base rate fallacy. This bias occurs when individuals fail to incorporate base rate probabilities into their judgments.
Why the other options are wrong
- A. Hindsight bias is the tendency to see past events as more predictable than they actually were, which is not applicable to a current diagnostic scenario.
- B. Anchoring bias involves relying too heavily on an initial piece of information, but the physician's reliance here is on statistical prevalence, not just any initial data point.
- C. Confirmation bias involves seeking out information that confirms existing beliefs, not necessarily ignoring base rates.
Base Rate Fallacy
The base rate fallacy is a cognitive bias in which people tend to ignore base rate information (i.e., the general prevalence of an event or characteristic) in favor of specific, but less reliable, individuating information.
- Involves neglecting statistical probabilities.
- Often prioritizes anecdotal or specific details over general data.
- Leads to flawed judgments or decisions.
Memory trick: Don't Neglect Basic Statistics, Or You'll Fall.