Dysrationalia: Why smart people do dumb things

Globe and Mail

Give this problem a shot before you keep reading, but don't feel badly if you get it wrong.
Bob is in a bar, looking at Susan. But she is looking at Pablo. Bob is married. Pablo is not.
Is a married person looking at an unmarried person? The answer could be (a) yes, (b) no or (c) cannot be determined.

Roughly 80 per cent of people choose (c), but it is not the correct answer, says Keith Stanovich, a professor of human development and applied psychology at the University of Toronto.
He studies why smart people do stupid things - or, in more scientific terms, how intelligence is distinct from rationality. His work offers insight into important cognitive abilities that are not measured by IQ tests. It also suggests that deficits in real-world reasoning can be corrected, whether in adults or in children.

He says most people get the Bob-Susan-Pablo problem wrong because they tend to be "cognitive misers" - they put as little mental effort as possible into solving a problem. In this case, they quickly jump to the conclusion that they don't have enough information rather than making the effort to see if they do.