Intelligence tests are as a measure of motivation, revealed in a study conducted by University of Pennsylvania researchers. Getting a high score in an IQ test requires both intelligence and tendency to motivate the test-taker.
Incentives were also found to increase IQ scores by a noticeable margin.
For the findings, the researchers first analyzed previous studies of how material incentives affected the performance of more than 2,000 people in intelligence tests.
They found that incentives increased all IQ scores, but particularly for those of individuals with lower baseline IQ scores.
Then the researchers tested how motivation impacted on the results of IQ tests and also on predictions of intelligence and performance in later life.
By using data from a long-term study of 250 boys from adolescence to early adulthood, they were able to conclude that some individuals try harder than others in conditions where the stakes are low.
Therefore, the study said, "relying on IQ scores as a measure of intelligence may overestimate the predictive validity of intelligence."
The study is published in Proceedings of the National Academy of Sciences.