Laziness and intelligence are barely related. Across 272 samples, conscientiousness was essentially uncorrelated with IQ, so smart people are not lazier.
Dr. Russell T. WarneChief Scientist
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Smart people are not lazier than anyone else. In a meta-analysis of 272 samples and more than 160,000 people, conscientiousness, the personality trait that runs from diligent and organized to careless and lazy, was essentially uncorrelated with intelligence, and people who enjoy hard thinking tend to score somewhat higher, not lower.
The idea that brilliant people coast is popular anyway. This page looks at what large personality studies show, where the "smart people are lazy" claim came from, what brain research on "neural efficiency" means, and how much effort changes an IQ score.
Are smart people lazy? What the largest studies show
Psychologists do not measure "laziness" directly. The closest trait is "conscientiousness," one of the Big Five personality traits, which covers self-discipline, orderliness, dutifulness and the drive to achieve. A lazy person, in this sense, scores low on conscientiousness.
The best evidence comes from Jeromy Anglim and colleagues, who pooled 272 samples with a combined 162,636 participants in 2022. Openness to experience (ρ = .20) and neuroticism (ρ = -.09) were the strongest Big Five correlates of intelligence. Conscientiousness as a whole was unrelated to it. At the level of narrower facets, orderliness had a small negative correlation with intelligence, so brighter people were slightly less drawn to routine and structure. That is a preference for flexibility, which is a different thing from avoiding work.
Single studies sometimes find a small negative link. Beatrice Rammstedt and colleagues tested a heterogeneous German population sample and replicated a negative association between conscientiousness and cognitive ability, and they found that the size of this association depended on whether people were in the labor force. One explanation researchers have proposed is compensation: people who find intellectual tasks harder may learn to work more carefully and persistently to keep up. Either way, the correlations are close to zero. Knowing someone's IQ tells you almost nothing about how hardworking they are, and the reverse is also true.
Where "smart people are lazy" came from
A small 2016 study is the usual source for the claim. Todd McElroy and colleagues screened undergraduates at Appalachian State University on "need for cognition," a questionnaire measure of how much people enjoy effortful thinking. They took 30 students from the top 10% and 30 from the bottom 10% of the screening and had them wear wrist accelerometers for a week. The high-need-for-cognition group was less physically active overall, a difference that explained about 11% of the variance in activity. The gap was clear on weekdays and not statistically significant on weekends.
The study did not include an intelligence test. Need for cognition is a preference for thinking, and the participants were all college students in the middle of a semester. Translating "students who like to think moved around less during the week" into "intelligent people are lazy" skips several steps.
Need for cognition is related to intelligence, but in the opposite direction from the meme. Sophie von Stumm and Phillip Ackerman pooled 112 studies with about 60,000 participants on "investment traits," the tendencies (including need for cognition) that lead people to spend time and effort on intellectual activity. These traits correlated with markers of adult intellect, such as crystallized intelligence and academic performance, at an average of about .30. People who like to think tend to know more, plausibly because they spend more time thinking.
Physical activity does not favor the less intelligent either. In a cohort of more than 1.2 million Swedish men tested at military conscription around age 18, Maria Åberg and colleagues found that better cardiovascular fitness went with higher intelligence scores after adjusting for confounders, and the pattern held within pairs of identical twins. Muscle strength showed no association. Our article on whether exercise can affect your IQ score looks at what exercise experiments show.
Neural efficiency: do bright brains work less hard?
There is one sense in which smarter brains can look "lazy." The "neural efficiency" hypothesis, which traces to brain-imaging work by Richard Haier and colleagues in the late 1980s, says that brighter people show lower brain activation while doing the same cognitive task. In a 2009 review, Aljoscha Neubauer and Andreas Fink concluded that the pattern appears mainly on tasks of low to moderate difficulty and mainly in frontal brain areas. On very complex tasks, more able people seem to invest more brain resources, and activation correlates positively with ability.
A later fMRI study by Beate Dunst and colleagues compared 28 people of lower and 30 of higher intelligence. When both groups worked on the same items, the brighter group needed less activation. When each person got items matched to their own ability level, the difference disappeared. Neural efficiency describes how hard a task is for a given brain. It says nothing about willingness to work.
Does effort change IQ scores?
A related question is whether low effort makes people look less intelligent than they are. For years the standard answer cited a 2011 PNAS meta-analysis by Angela Duckworth and colleagues, which reported that paying people to do well raised IQ scores by an average of g = 0.64, close to 10 IQ points. That paper was retracted in 2025. One study in it, by Stephen Breuning and W. F. Zella, had itself been retracted, and it supplied about 24% of the meta-analytic sample. Without it, the effect fell to g = 0.47, and after correcting for publication bias it fell to 0.16 with a confidence interval that included zero. Our article on the impact of motivation on IQ tells that story in full.
Newer experiments point to a small effect:
• Six studies, 4,208 adults: Timothy Bates and Gilles Gignac found that self-reported effort correlated about .28 with cognitive test scores. In three randomized trials with 1,201 participants, cash incentives did not significantly raise scores in any study, and the combined effect was d = 0.166, about 2.5 IQ points.
• A 99-person incentive experiment: Gignac found that a moderate financial incentive increased how hard adults said they tried but did not significantly change their intelligence test scores.
• Low-stakes testing of 219 students: Gignac and colleagues found that test-taking motivation correlated about .20 with general intelligence, but the link came entirely from the low-to-moderate end of motivation. About 6% of the students appeared insufficiently motivated during the intelligence tests.
The practical reading is that someone who gives a test reasonable effort gets a score that reflects their ability. Very low effort can pull a score down, so a person who rushes through a test half-interested may score lower than they would otherwise. Part of the effort-score correlation also runs the other way, since people who find the items manageable tend to report trying harder.
Laziness, procrastination and getting things done
Because conscientiousness and intelligence are close to independent, they add up. A person can be bright and disorganized, or average in reasoning ability and highly reliable, and both traits contribute separately to how well things go at school and work. Anglim and colleagues describe conscientiousness as mostly an independent factor that leads to better performance through the steady application of effort.
Putting work off is a related but separate habit, and our page on IQ and procrastination covers what research says about it. When thinking about laziness and IQ in real people, keep the usual confounds in mind. Education, employment and age all shape both test scores and how organized people appear, which is why studies that sample only students or only one occupation can find links that vanish in broader samples.
Frequently asked questions
Is laziness a sign of intelligence?
No. Conscientiousness, the trait that captures diligence versus laziness, was essentially uncorrelated with intelligence in a meta-analysis of more than 160,000 people.
Are lazy people smarter than active people?
There is no good evidence for that. The 2016 study behind the claim compared 60 students on enjoyment of thinking and never measured intelligence, and in 1.2 million Swedish conscripts, fitter young men scored higher on intelligence tests.
Why do smart people seem lazy?
Bright people may finish easy tasks with less visible effort, and their brains show lower activation on easy and moderate tasks. They are also slightly less drawn to order and routine, which can look like disorganization.
Does not trying hard lower your IQ score?
A little, if effort is very low. Recent incentive experiments suggest that extra motivation adds only about 2.5 IQ points on average, and the retracted 2011 meta-analysis that suggested about 10 points should no longer be cited.
Is need for cognition the same as intelligence?
No. Need for cognition is how much a person enjoys effortful thinking, and investment traits of this kind correlate about .30 with markers of adult intellect.
The takeaway
Laziness and intelligence are close to unrelated. Conscientiousness shows essentially no correlation with IQ in very large samples, people who enjoy thinking tend to score somewhat higher, and the study behind the "smart people are lazy" headline never measured intelligence. Effort matters for test scores only at the low end. If you want a score that reflects your reasoning ability, give the test your honest attention and take a full-length online IQ test.
References
1. Anglim, J., Dunlop, P. D., Wee, S., Horwood, S., Wood, J. K., & Marty, A. (2022). Personality and intelligence: A meta-analysis. Psychological Bulletin, 148(5-6), 301-336. [doi.org/10.1037/bul0000373](. doi.org
2. Rammstedt, B., Danner, D., & Martin, S. (2016). The association between personality and cognitive ability: Going beyond simple effects. Journal of Research in Personality, 62, 39-44. [doi.org/10.1016/j.jrp.2016.03.005](. doi.org
3. McElroy, T., Dickinson, D. L., Stroh, N., & Dickinson, C. A. (2016). The physical sacrifice of thinking: Investigating the relationship between thinking and physical activity in everyday life. Journal of Health Psychology, 21(8), 1750-1757. [doi.org/10.1177/1359105314565827](. doi.org
4. von Stumm, S., & Ackerman, P. L. (2013). Investment and intellect: A review and meta-analysis. Psychological Bulletin, 139(4), 841-869. [doi.org/10.1037/a0030746](. doi.org
5. Åberg, M. A. I., Pedersen, N. L., Torén, K., Svartengren, M., Bäckstrand, B., Johnsson, T., Cooper-Kuhn, C. M., Åberg, N. D., Nilsson, M., & Kuhn, H. G. (2009). Cardiovascular fitness is associated with cognition in young adulthood. Proceedings of the National Academy of Sciences, 106(49), 20906-20911. [doi.org/10.1073/pnas.0905307106](. doi.org
6. Neubauer, A. C., & Fink, A. (2009). Intelligence and neural efficiency. Neuroscience & Biobehavioral Reviews, 33(7), 1004-1023. [doi.org/10.1016/j.neubiorev.2009.04.001](. doi.org
7. Dunst, B., Benedek, M., Jauk, E., Bergner, S., Koschutnig, K., Sommer, M., Ischebeck, A., Spinath, B., Arendasy, M., Bühner, M., Freudenthaler, H., & Neubauer, A. C. (2014). Neural efficiency as a function of task demands. Intelligence, 42, 22-30. [doi.org/10.1016/j.intell.2013.09.005](. doi.org
8. Duckworth, A. L., Quinn, P. D., Lynam, D. R., Loeber, R., & Stouthamer-Loeber, M. (2011). Role of test motivation in intelligence testing (retracted 2025; retraction notice: Proceedings of the National Academy of Sciences, 122(18), e2508040122). Proceedings of the National Academy of Sciences, 108(19), 7716-7720. [doi.org/10.1073/pnas.2508040122](. doi.org
9. Bates, T. C., & Gignac, G. E. (2022). Effort impacts IQ test scores in a minor way: A multi-study investigation with healthy adult volunteers. Intelligence, 92, 101652. [doi.org/10.1016/j.intell.2022.101652](. doi.org
10. Gignac, G. E. (2018). A moderate financial incentive can increase effort, but not intelligence test performance in adult volunteers. British Journal of Psychology, 109(3), 500-516. [doi.org/10.1111/bjop.12288](. doi.org
11. Gignac, G. E., Bartulovich, A., & Salleo, E. (2019). Maximum effort may not be required for valid intelligence test score interpretations. Intelligence, 75, 73-84. [doi.org/10.1016/j.intell.2019.04.007](. doi.org
Hero image: Empty Hammock at South Yuba Campground, by Ginessa Stark, Bureau of Land Management, public domain. Via Wikimedia Commons.
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