Biases and Heuristics That May Impede Optimal Patient Decisions
| Cognitive or Affective Bias/Heuristic | Clinical Example |
|---|---|
| Availability heuristic: being influenced by what is most readily available in memory—recent, rare, and vivid events hold exceptional sway | A parent refuses to vaccinate her child after she sees an isolated media report of a child who developed autism after being vaccinated |
| Feeling vulnerable effect: being influenced by affective risk perceptions instead of cognitive ones | A smoker correctly estimates her probability of developing lung cancer to be high but reports that she nevertheless does not believe she is susceptible, and hence does not quit smoking |
| Focusing effect/side-effect aversion: being influenced sub-stantially more by short-term concerns and interests than by long-term goals | A patient chooses to forgo recommended colorectal screening because of its inconveniences despite wishing to live as long as possible |
| Gambler’s fallacy: being influenced by unrelated past Occurrences | A patient thinks that because she has developed so many incident health problems in the past year, she is unlikely to also develop breast cancer because she is “due for a break.” She thus skips her mammography |
| Impact bias/affective forecasting error: being influenced by inaccurate projections of future states | A patient delays getting a colostomy because he predicts that he will be extremely unhappy, even though studies show that those who have under- gone the procedure rate their quality of life as being the same as before, and report wishing they had done it sooner2 |
| Omission bias: preferring inaction to avoid harm even though it may cause a similar or greater harm than the action | A patient with atrial fibrillation refuses to take warfarin because she is concerned about causing a hemorrhagic stroke, despite the greater risk of ischemic stroke if she does not take the warfarin |
| Escalation/cascade effect: preferring the path already taken in favor of other paths that might clearly produce better results but require a change of habit or routine | Patients continue to make choices that produce negative health effects (eg, not exercising, smoking) because they have been doing it for so long already |
| Sunk cost bias: continuing with a plan of action, even when it is clear that there is no payoff, just because resources have already been invested into that plan | A patient with osteoarthritis continues taking a drug just because she already purchased a large supply even though after many months of taking it she notices no difference in her knee pain |