How can someone with a high IQ have certain kinds of intellectual deficiencies? Put another way, how can a "smart" person act foolishly?
IQ tests fall down when it comes to measuring those abilities crucial to making good judgements in real-life situations. That's because they are unable to assess things such as a person's ability to critically weigh up information, or whether an individual can override the intuitive cognitive biases that can lead us astray.
"IQ tests measure an important domain of cognitive functioning and they are moderately good at predicting academic and work success. But they are incomplete. They fall short of the full panoply of skills that would come under the rubric of 'good thinking'."
There is no proven test of rational thinking skills that could be used alongside IQ tests. "It is not enough to say what intelligence is not measuring, you have to propose alternative ways of measuring rationality," says Kahneman. Stanovich maintains that while developing a universal "rationality-quotient (RQ) test" would require a multimillion-dollar research programme, there is no technical or conceptual reason why it could not be done. An RQ test could measure the extent to which people are inclined to use what capacity they have.