Belief bias: believable conclusions feel logically valid

Correct: B — The conclusion is believable in real-world terms

Participants judged the logical validity of syllogisms whose conclusions were either believable or unbelievable in everyday terms. Believable invalid conclusions were endorsed about twice as often as unbelievable invalid conclusions; the reverse pattern appeared for valid syllogisms with unbelievable conclusions. The result demonstrates belief bias — real-world plausibility intrudes on formal-validity judgements — and is one of the strongest pieces of evidence for dual-process accounts: System 1 retrieves a believability assessment, System 2 must override it to produce the formal answer.