An IQ score may say more about whether you're a hard worker or a slacker than about how smart you are. And hard work may be at least as important as intelligence in determining who will be a successful student and adult, researchers say.
An IQ score can dramatically misjudge intelligence, depending on how motivated the person is when taking the IQ test, scientists discovered.
Academic performance, level of education, job performance, criminal record and even physical health and longevity are often linked to the person's intelligence quotient, or IQ score, which tends to suggest intelligence is primarily responsible for all these outcomes.
But do intelligence tests really measure intelligence and only intelligence?
"I was giving IQ tests to children and realized that there was a fair amount of variation in results that seemed to vary on how hard kids tried," said researcher Angela Lee Duckworth, a psychologist at the University of Pennsylvania who focuses on differences between individuals.
To see what effects motivation had on IQ scores, Duckworth and her colleagues analyzed 46 separate, previously collected datasets involving more than 2,000 volunteers given incentives such as money or candy for taking such tests. The researchers found that incentives noticeably boosted IQ scores, with the increase most pronounced for test-takers who had posted lower IQ scores when not given incentives. [Children Who Get Spanked Have Lower IQs]
"IQ test scores do not necessarily reflect a child or adult's actual intelligence, particularly when we give IQ tests under circumstances where there are no consequences for good or bad scores," Duckworth told LiveScience.
In other words, earning a high IQ score is apparently linked with both high intelligence and high motivation, and a low score could result from the lack of either factor.
The scientists also analyzed more than 250 boys as they took intelligence tests, judging them for signs of low motivation, such as refusing to attempt tasks, forcing the examiners to work hard to get them to try a task, or expressing the desire for the exams to end as quickly as possible. The researchers found that boys with lower motivation typically showed lower IQs.
These boys were part of a long-term study that followed them from adolescence to early adulthood. The researchers found that once motivation was taken into account, how well or poorly the boys did on the IQ test was less predictive of how they did later in life in terms of academic achievement, level of education, employment status and number of criminal convictions. This contradicted past findings suggesting that IQ is linked with all these elements.
"IQ scores may predict various outcomes in life, but in part for reasons that intelligence tests weren't designed for," Duckworth said. Sheand her colleagues detailed their findings online April 25 in the journal Proceedings of the National Academy of Sciences.
"The most important implication of this work is that people's IQ may have been misestimated by an indefinite amount," said University of Michigan psychologist Richard Nisbett, who did not participate in this research. "One future direction would be to see if there is any link here with, say, socioeconomic status."
Some people might say that motivation is part of intelligence, "but I think most people would say they are not the same, that we know friends who are brilliant but never get anything done for lack of trying," Duckworth said. "One direction this research can go from here is to show how people might do better in life if they worry less about intelligence and more on how hard they work, which appears to matter at least as much to success."
"Duckworth and colleagues have produced a great research study, but the fact that one of the most prestigious scientific journals in the world would publish a study showing motivation is important in test performance and its predictive outcomes — duh! — shows how off-track our society has gone in its acceptance of commercial persuasive appeals to buy into standardized tests as some kind of panacea for predicting almost any outcome in life that we value," said psychologist Robert Sternberg at Oklahoma State University. "Little wonder that in many Asian societies with much higher levels of achievement in school, the emphasis is on motivation rather than on so-called ability-test scores."
Sternberg calls these standardized tests "minor cosmetic variants of tests used a century ago," suggesting instead we should recognize that various skills are needed for success in life.
Sternberg suggested we also seek "to assess motivation as well as creativity, practical skills, wisdom, and even ethics. If we did, we might find our society advancing to levels of economic productivity — and, for that matter, well-being — that we previously believed to be out of reach."
Live Science newsletter
Stay up to date on the latest science news by signing up for our Essentials newsletter.