In the Wason selection task, you see four cards: A, K, 4, 7. The rule is: 'If a card has a vowel on one side, it has an even number on the other.' Which cards must you flip to properly test whether the rule is violated?
AA and 7 — A to check for an even number, 7 to check there is no vowel hiding behind it
BA and 4 — A to confirm the rule, 4 to confirm it further
CA, 4, and 7 — test all potentially relevant cards
DOnly A — it is the only card guaranteed to be relevant
You flip A (a vowel — must verify the other side is even) and 7 (an odd number — must verify there is no vowel, since a vowel behind 7 would falsify the rule). Card 4 is irrelevant: whether it has a vowel or consonant behind it, the rule ('vowel → even') is not violated. Card K is irrelevant: K is not a vowel, so the rule makes no claim about it. Most people choose A and 4 — seeking confirmation rather than falsification. This is confirmation bias in action: the logically necessary move is to look for what could prove the rule false.
Question 2 Multiple Choice
A researcher believes a new drug lowers blood pressure. Her study returns ambiguous results. She concludes the study was underpowered and needs repeating. A skeptic suggests she would have accepted the same ambiguous data as valid evidence if it had supported her hypothesis. This is an example of which stage of confirmation bias?
ABiased interpretation — identical ambiguous evidence is judged by a different standard depending on whether it confirms or disconfirms the hypothesis
BBiased memory — the researcher is forgetting the negative aspects of the data
CBiased search — the researcher is selecting only studies that support her belief
DNormal scientific skepticism — it is always appropriate to demand replication of ambiguous findings
Biased interpretation occurs when the same evidence is processed differently depending on its direction. Ambiguous results that support a hypothesis are read as 'suggestive evidence'; ambiguous results that contradict it are read as 'methodological failure.' This double standard is not obvious to the person exhibiting it — they experience themselves as applying rigorous standards, not as being biased. It is one of the subtler and more damaging forms of confirmation bias because it operates under the cover of apparent rigor.
Question 3 True / False
Confirmation bias can distort reasoning in trained scientists and people who are explicitly aware of the bias.
TTrue
FFalse
Answer: True
True. Studies consistently show that expertise and awareness of confirmation bias do not eliminate it. Scientists, judges, doctors, and logicians exhibit it, often while believing they are reasoning objectively. The most effective countermeasures are not introspective — they are structural practices like pre-registration (committing to hypotheses before data collection), adversarial collaboration, and explicit devil's advocate roles. Awareness is a necessary but insufficient condition for mitigation.
Question 4 True / False
The most effective way to counteract confirmation bias is to consciously remind yourself to consider opposing viewpoints when forming beliefs.
TTrue
FFalse
Answer: False
False. Research shows that introspective reminders — 'think about the other side,' 'be objective' — have limited effectiveness against confirmation bias because the bias often operates below conscious awareness. Biased search, interpretation, and memory are automatic processes that awareness does not reliably interrupt. The most effective countermeasures are structural: pre-registering hypotheses, actively assigning someone to argue the opposing view, designing tests that seek falsification rather than confirmation. The goal is to make the search for disconfirming evidence a procedural habit, not a conscious effort applied case by case.
Question 5 Short Answer
Why does consistently seeking only confirming evidence create a self-reinforcing cycle that makes beliefs increasingly resistant to revision?
Think about your answer, then reveal below.
Model answer: When you seek only confirming evidence, each piece of confirmation strengthens the belief, making it feel more justified and less in need of challenge. At the same time, disconfirming evidence is systematically absent from your search (biased search), interpreted charitably as inconclusive when encountered (biased interpretation), and forgotten more readily (biased memory). The belief's apparent evidential support grows not because the underlying truth warrants it, but because the feedback loop filters out everything that would challenge it — creating an epistemic bubble that becomes harder to exit as the belief becomes more entrenched.
This self-reinforcement is why confirmation bias is considered the most pervasive obstacle to objective reasoning. It does not require malicious intent or obvious motivated reasoning — it operates through ordinary cognitive processes applied asymmetrically. The cycle is broken only by structural interventions that force falsification-seeking, not by the believer simply 'trying harder' to be objective.