The finding flies in the face of long-held ideas about intelligence and cognition that regard IQ as a stable, predictive measure of mental horsepower. "This study tells us the idea that IQ is something we can reliably measure in isolation without considering how it interacts with social context is essentially flawed," says Steven Quartz, professor of philosophy at Caltech and one of the authors of the new study.
To investigate the impact of social context on IQ, the researchers divided a pool of 70 subjects into groups of five and gave each individual a computer-based IQ test. After each question, an on-screen ranking showed the subjects how well they were performing relative to others in their group and how well one other person in the group was faring. All of the subjects had previously taken a paper-and-pencil IQ test, and were matched with the rest of the group so that they would each be expected to perform similarly on an IQ test.
At the outset, all of the subjects did worse than expected on this "ranked group IQ task."