Asking people to work harder on tests of mental ability doesn’t actually improve their scores. Recent research published in intelligence and cognitive ability found that while monetary rewards were successful in motivating people to try harder, increased motivation did not lead to higher scores on cognitive tests. These results challenge the common belief that intelligence measures largely reflect a person’s willingness to engage with the material rather than their actual cognitive limitations.
Researchers have debated for decades the exact relationship between individual motivation and measured cognitive ability. Several prominent social theories propose that a significant portion of the differences seen in intelligence scores can be attributed to how much effort individuals exert during exams. Under this framework, two people with the same baseline intelligence can receive vastly different scores simply because one person values ​​results more and focus more.
A famous analysis from more than a decade ago supports this point of view, arguing that offering small monetary rewards can significantly improve test performance. This idea suggested that basic intelligence tests might measure motivation as much as they measure mental ability. That initial analysis ultimately collapsed under scrutiny, as some of the specific research papers included in the review contained fraudulent data and were retracted by their publishers.
Other observational studies on effort have relied on asking participants how much effort they exerted only after the test has already been completed. This approach introduces a serious flaw known as reverse causation. When people feel like they’re doing well at work, they tend to report trying harder. After all, it’s not that effort produces good performance, but that good performance produces a feeling of high effort.
Timothy Bates, a psychology researcher at the University of Edinburgh, designed a series of new experiments to solve this measurement problem. Bates wanted to isolate the influence of the true direction of effort on mental performance. To do this, we needed to precisely manipulate how much effort participants were willing to put in. We also needed to measure the intentions of volunteers before they actually started testing.
This experimental strategy relies on introducing an external influence, in this case a monetary reward, to randomly adjust participants’ motivation levels. Researchers can encourage some groups of people to work harder than others by tying financial bonuses to specific goals. If effort really improves intelligence scores, then the group that was given the money should show a clear spike in performance. This model allows scientists to eliminate invisible variables and focus entirely on the direct path from increased effort to final test score.
In the first phase of the study, Bates developed a survey to measure effort proactively. He asked nearly 400 adult volunteers to rate their intended effort before taking timed reasoning and grammar tests. In this test, participants had 90 seconds to evaluate simple sentences and decide whether they were logically true or false. Because he captured their intentions early on, participants were not able to modify their answers based on whether the question was easy or difficult.
Bates confirmed that his new measure of positivity is consistent with established behavioral indicators. He found that those who committed to working hard on his research also had a strong track record of reliably completing other online tasks. He looked at the test results and noticed an early hint of the final conclusion. There was no real relationship between the amount of effort participants committed to and the score they ultimately achieved on the logic test.
In the second phase, we scaled up the experiment to test for direct causality. Bates recruited 500 adults to take a visuospatial test. This particular assessment required participants to mentally imagine folding a piece of paper. Volunteers first completed a baseline version of the paper folding test and then filled out a new questionnaire asking them to state their intended effort for the second question.
At this stage, half of the participants were randomly selected to receive a special offer. If they were able to improve their score by at least 1 point compared to their first attempt, they were offered a monetary bonus of 2 British pounds. All others progressed to the standardized test group without any bonus offer.
The financial incentive worked exactly as intended. Participants in the reward group reported a clear increase in their willingness to work hard on the second test. Despite this increased motivation, actual performance on spatial reasoning problems did not change. The causal effect of increased effort on cognitive scores was nearly zero, and the small variation in performance between groups was not statistically significant.
To test these results, Bates conducted a third experiment with more than 1,200 adult participants. This final test used a completely different set of survey questions to measure intended effort. Bates borrowed an effort scale originally developed for large-scale international mathematics and science research. The use of secondary tools ensured that the results were not just a quirk of his own research design.
Volunteers again responded to the promise of financial rewards and increased their planned efforts. Similar to the second experiment, this increased motivation did not lead to improved test scores on the paper-folding task. Results across multiple independent samples and a variety of measurement studies refute the idea that working harder leads to improved cognitive scores.
Taken together, the results of these experiments suggest that basic mental abilities are largely isolated from short-term willpower. Although people can choose to direct their attention to specific tasks, they cannot force the underlying cognitive processing to operate beyond set limits. By analogy, a person may focus their eyes on a distant object, but if the object is too far away to see, that concentration cannot change the basic sensitivity of the visual system.
This study strengthens the general validity of standard cognitive tests. The test remains an accurate reflection of a person’s baseline reasoning skills because it is not easily distorted by changes in motivation levels. Educators and psychologists who rely on these metrics can be fairly confident that their scores represent actual ability and not just compliance or enthusiasm on test day.
This finding does not suggest that hard work and perseverance are generally useless traits. Hard work and goal setting remain highly effective strategies for long-term success, especially when learning new skills, learning information over time, or completing long-term projects. Effort can be very helpful in overcoming frustration and staying focused. The findings focus specifically on short-term attempts to temporarily improve brain power during isolated assessments.
Future research should continue to investigate the precise characteristics of these newly validated pretest surveys to ensure we accurately capture participants’ intentions. On the other hand, educators seeking to improve student outcomes may shift their focus to proven instructional techniques. Strategies such as planned time spent on a task and spaced repetition over weeks or months definitely help students learn. These strategies offer a more realistic path to academic improvement than expecting sudden efforts to improve students’ basic cognitive abilities.
The study, “Is Effort Enough? A Causal Analysis of the Relationship Between Effort and IQ Suggests Otherwise,” was authored by Timothy Bates.
