Cognitive Daily

IQ has been the subject of hundreds, if not thousands of research studies. Scholars have studied the link between IQ and race, gender, socioeconomic status, even music. Discussions about the relationship between IQ and race and the heritability of IQ (perhaps most notably Steven Jay Gould’s Mismeasure of Man) often rise to a fever pitch. Yet for all the interest in the study of IQ, there has been comparatively little research on other influences on performance in school.

Angela Duckworth and Martin Seligman estimate that for every ten articles on intelligence and academic achievement, there has been fewer than one about self-discipline. Even so, the small body of research on self-discipline suggests that it has a significant impact on achievement. Walter Mischel and colleagues found in the 1980s that 4-year-olds’ ability to delay gratification (for example, to wait a few minutes for two cookies instead of taking one cookie right away) was predictive of academic achievement a decade later. Others have found links between personality and college grades, and self-discipline and Phi Beta Kappa awards. Still, most research on self-discipline has achieved inconsistent results, possibly due to the difficulty of measuring self-discipline. Could a more robust measure of self-discipline demonstrate that it’s more relevant to academic performance than IQ?

To address this question, Duckworth and Seligman conducted a two-year study of eighth graders, combining several measures of self-discipline for a more reliable measure, and also assessing IQ, achievement test scores, grades, and several other measures of academic performance. Using this better measure of self-discipline, they found that self-discipline was a significantly better predictor of academic performance 7 months later than IQ.

How did they arrive at this result? They studied a group of 8th-graders at the beginning of the school year. They used five different measures of self-discipline: the Eysenck Junior Impulsiveness scale (a 23-question survey about impulsive behavior), the Brief Self-Control Scale (13 questions measuring thoughts, emotions, impulses, and performance), two questionnaires in which parents and teachers rated the student’s self-discipline, and a version of Mischel’s delay of gratification task. Students were given an envelope containing $1, and were told they could spend it immediately or bring it back in a week for a $2 reward. The students were also given an IQ test (OLSAT7, level G).

At the end of the school year, students were surveyed again and several measures of academic performance were taken. The data included final GPA (grade point average), a spring achievement test, whether they had been admitted to the high school of their choice, and number of hours they spent on homework. All except two measures correlated more strongly to self-discipline than to IQ. Scores on spring achievement tests were correlated both to self-discipline and IQ, but there wasn’t a significant difference. Duckworth and Seligman suggest that this could be partially due to the fact that achievement tests are similar in format to IQ tests. The other area where there was no significant difference was in school absenses.

Most impressive was the whopping .67 correlation between self-discipline and final GPA, compared to a .32 correlation for IQ. This graph dramatically shows the difference between the two measures:

i-8d871dc59428cdf5a5cc3ff6757e09c0-iq.gif

Both IQ and self-discipline are correlated with GPA, but self-discipline is a much more important contributor: those with low self-discipline have substantially lower grades than those with low IQs, and high-discipline students have much better grades than high-IQ students. Even after adjusting for the student’s grades during the first marking period of the year, students with higher self-discipline still had higher grades at the end of the year. The same could not be said for IQ. Further, the study found no correlation between IQ and self-discipline—these two traits varied independently.

This is not to say this study will end the debate on IQ and heredity. The study says nothing about whether self-discipline is heritable. Further, the self-discipline might be correlated differently with achievement for different populations; this study covered only eighth graders in a relatively privileged school. Perhaps self-discipline has a different role at other ages, or in more diverse populations (though the study group was quite ethnically diverse—52% White, 31% Black, 12% Asian, and 4% Latino). Perhaps the most important question which remains is how best to teach children self-discipline—or whether it can be taught at all.

Duckworth, A.L., & Seligman, M.E.P. (2005). Self-discipline outdoes IQ in predicting academic performance of adolescents. Psychological Science, 16(12), 939-944.

Comments

  1. #1 Gary Peterson
    December 14, 2005

    Interesting research. I try to help my students to learn the differences between experiments and correlational research. You called it an experiment and seem to be toying with causal inferences regarding self-discipline. Did I miss something?

  2. #2 Dave Munger
    December 14, 2005

    You’re right. I was careless with my language in that final paragraph. I’ve fixed it now.

  3. #3 Tommy
    December 15, 2005

    I don’t think that all international readers understand that GPA stands for General Point Average.

    Is self-discipline the same as (high)motivation. Still there would be boundaries to what a highly motivated or highly intelligent person would/could do?

    Also didn’t you do a previous article that said that if you are smart (or think that) you are more likely to assume you are right (and won’t check) versus somebody who will always check what they do? Any relation?

  4. #4 Dave Munger
    December 15, 2005

    Thanks, Tommy. I fixed that, too (though it’s “Grade Point Average,”—a weighted average of school grades). If we all pitch in, we can make this article really shine!

    I don’t think self-discipline is the same as high motivation. My son is highly motivated to play video games, so we told him if he got good grades, he could play whenever he wanted. But he doesn’t have the self-discipline it takes to get high enough grades (not yet—we haven’t given up on him!).

    re: boundaries—I’m a real optimist here. I think there are few absolute limits to what the human mind can do. We know that IQ can be improved with education, and I suspect self-discipline could be as well. Maybe there are limits, but I’d prefer to talk about potential (especially with respect to my son!).

    You might be thinking about an article we did on working memory as it related to “choking” under pressure. I’m disinclined to say this is related to the self-discipline issue, but someone would have to design a study to find out for sure.

  5. #5 Mind Hacks
    December 16, 2005

    2005-12-16 Spike activity

    Quick links from the past week in mind and brain news: British and American smiles may be different, claims book author. Cognitive Daily on the neglected area of self-discipline and its importance in acheivement. Author Jay Ingram on the evidence that …

  6. [...] IQ is an overrated measure. It cannot predict success beyond a few specific analytical tests. Concerning overall academic performance or quality of life it has little predictive value. Looking for alternative measures two researchers have turned to self-dicipline. Their study shows a much higher correlation to academic success for self-discipline than IQ. [...]

  7. #7 glen markie
    December 16, 2005

    Yes I’m a guy with low self-discipline and I’ve always performed abysmally in every aspect of my life. In school I was always the laziest kid in class but always did very well in exams. Never did figure out why I was so good at exams and it was the only thing I have ever done well in my entire life.
    Good article, I’m gonna use it for reference.

  8. [...] Self-Discipline: High IQ: Not as good for you as you thought (tags: iq intelligence self-discipline) [...]

  9. #9 deli lama
    December 17, 2005

    speaking as someone with a high IQ and limited self discipline, all i have to say is – duh-
    IQ has nothing to do with your definition of success-
    it simply has to do with seeing the world in different ways.
    this may or may not aid in your success- depending on what your definition of success is.
    by your apparent definition, well, no &^$#$ kidding self discipline is more important.

  10. #10 Dave Munger
    December 17, 2005

    Deli Lama,

    Often pscyhological research merely confirms what some people believe to be “obvious.” This does not make the results invalid, espcially when you consider that few other studies have addressed this area of research.

    On the other hand, I believe that many would find this result far from obvious. Consider how many people seem to think that IQ is the holy grail of academic achievement—they believe that those who are “smart” do better in school. Now we have clear evidence that hard work may be more important. I think this article could help a lot of people who think they are not “smart enough” to succeed.

  11. #11 GCT
    December 17, 2005

    If IQ is to be equated with inherent intelligence e.g. fluid intelligence, then all other aspects of arguments attempting to dispute its merit is senseless. IQ tests attempt to measure such a potential as we believe it to exist….such a trait has to do with innate intellectual capacity (not just academic and an absolute measure against retardation.

    I suppose though, since IQ tests pertain are supposed to correlate with academic performance, the research is significant in the sense that another trait seemingly correlates better with academic performance.

    Still I would value potential over earnest discipline any day. I can’t really agree with the correlation though as I’ve seen many fail because of what seemed to be “low potential” despite the discipline.

  12. [...] Cognitive Daily skriver i dag om en forskningsundersøkelse som undersøkte sammenheng mellom intelligens, selvdisiplin og skoleresultater hos amerikanske 8.klassinger. Intelligens og intelligenstester har lang tradisjon i psykologien, og mens intelligenstester eller evnetester også brukes en del i Norge, er de nok enda mer brukt i USA. Selvdisiplin er derimot ikke et fenomen det skrives like mye om, selv om studier har funnet at fireåringers evne til å utsette belønning (for eksempel å klare og vente noen minutter for å få to kjeks, i stedet for å spise den ene som er tilgjengelig akkurat nå), henger sammen med hvilke karakterer de får på skolen (academic achievement) ti år senere. Generelt sett har studier om selvdisiplin vært inkonsistente fordi fenomenet er vanskelig å måle. [...]

  13. #13 christopher
    December 18, 2005

    “Still, most research on self-discipline has achieved inconsistent results, possibly due to the difficulty of measuring self-discipline.”

    i would argue that it goes further than that – it would say it’s the difficulty of *defining* ‘self-discipline.’

    “for example, to wait a few minutes for two cookies instead of taking one cookie right away.”

    why is this a measure of self-discipline? doesn’t it just become a question of desire (how much do i want two cookies)? does someone who would take a cookie now, but doesn’t like cookies enough to be enticed by two later get labeled undisciplined?

    the cookie example you gave was undoubtably given simply to make a point – but you get the idea. the definition and measurement of self-discipline would seem to be very tricky indeed, and additonally im suspicious that there’s a cultural/religious (protestant work ethic, catholic guilt, etc.) bias involved in a) wanting to define discipline as a causal factor for success, and b) coming up with a definition that is not-surprisingly similar to self-denial.

    of course additionally, this measurement of success was academic excellence. what about those who don’t do well in that environment, but excell in other areas, be it sports, journalism, creative arts, etc.?

    regardless, it would seem to me that what the correlative difference between iq and “self-discipline” shows, is that desire of some sort is a greater factor in one’s success than intellectual ability (at least as defined by iq) – at least in the range between successful (b grades as a final gpa of 80 would suggest), and very successful (a grades).

  14. #14 Knowledge Jolt with Jack
    December 20, 2005

    IQ vs. self discipline

    Dave Munger of Cognitive Daily writes High IQ: Not as good for you as you thought, in which he discusses research that looked at IQ and “self discipline” as predictors for academic performance. The surprise? Self-discipline was more highl…

  15. #15 The Unreasonable Man
    December 20, 2005

    High IQ: Not as good for you as you thought

    I’d not come across Cognitive Daily before – but they do a good job on presenting this research that shows that even bright kids would do well to work on their self-discipline if they want to really succeed. Both IQ

  16. [...] Cognitive Daily — High IQ: Not as good for you as you thought Published in: Whatever | on December 23rd, 2005 | [...]

  17. #17 Andeora
    December 25, 2005

    The article definitely makes a lot of sense. But I think that what makes IQ somewhat more important than self-discipline is that while the latter can be developed during one’s life, it does not seem very likely that that would also be the case with the former.

    Also, as has been pointed out by some people, there is also the question of motivation. I suspect many people with a high IQ find school somewhat too mentally restrictive, perhaps even boring, because it just isn’t challenging enough for them. I know I tend to feel that a lot and therefore when outside of school try to spend as little time on anything school-related as possible. When I do have some kind of personal motivation to focus on it, though, I am usually completely capable of getting myself together to do what needs to be done, though admittedly only for some short periods of time. I can simply learn so much more when I don’t use up all my time and energy on ‘what has to be done’ I guess.

    Too much self-discipline can actually be harmful I think, to one’s health anyway, because such people just keep pushing themselves to do everything as close to perfection as possible regardless of how they might be feeling. I know a few of such people and it can be pretty terrible to watch really, how they seem to just sacrifice everything else in the name of that couple of extra points in a test or being able to quote the textbook word by word if asked. The borders between too little, a good and necessary amount and too much of self-discipline are so vague really and vary from person to person.

    Perhaps people with a high IQ have less self-discipline because at least in their childhood years they often have less need for it? But if they were to end up in a situation where they truly needed it, they would probably be able to summon it at least for that time as well. Could the same be said about people with high self-discipline lacking the IQ though?

  18. #18 Marvin
    December 27, 2005

    Well, it is clear that very few people truly understand IQ. The title of this article was a bit of a bait and switch, but the emphasis on self-discipline is appropriate. The problem is that high IQ and self discipline work well together, better than either alone. By attempting to lower the importance of IQ in your readers’ minds, you are doing a grave disservice to the needs of the future.

    You seem a bit emotionally attached to the work of reducing the esteem of IQ among your readers. This could be a problem in terms of objectivity.

  19. #19 Dave Munger
    December 27, 2005

    Marvin,

    I’m curious as to why you believe that I’m “emotionally attached” to any argument about IQ. I’d also be interested in any references you might have to research suggesting that IQ and self-discipline “work well together.” Duckworth and Seligman found that IQ and self-discipline were not correlated.

  20. #20 Marvin
    December 27, 2005

    I think I see the problem. Being statistically correlated has nothing to do with the synergistics involved. Think of it as a pity that the two things are not better correlated, given how synergistic they are. As for being emotionally attached to an argument, that is really for you to determine.

    Society desperately needs a better grip on the concept of IQ.

  21. #21 Farida
    January 1, 2006

    One has to remember that GPA is derived from “work submitted” and scored. Low GPA scores by the less disciplined would reflect missing or late assignments. It is rare that someone with a high IQ will submit a below average paper or score below average on actual testing of the material which was studied. Most importantly, the graph also shows clearly that those with high IQ and less discipline can achieve close to the same results. With GPA as a measure of “Work”, discipline comes in handy. With IQ as a measure of intelligence, intellect comes in handy. In a world that is headed into the realm of ‘work smarter’ not ‘harder’, the disciplined will reach a plateau, where the intellectuals will be sought to come up with ‘work smarter’ solutions. Those intellectuals who are less disciplined and achieve high scores would make the best consultants in that case, as they have somehow figured out a way to achieve above average results by working less. They live and breathe the ‘work smarter’ not harder concept.

  22. #22 Maggie's Farm
    January 3, 2006

    Tues. Night Links

    The always-composed Hinderaker is provoked into a true blogger rant by Dean.China ratchets up controls of the press. CSMIQ vs. Self-Discipline. Cognitive Daily

  23. #23 Phil
    January 7, 2006

    Wasn’t there a substantial difference in the courses taken by high-IQ and low-IQ kids? Sure, you’ll get a better grade if you study harder in a less challenging course. Or did I miss something?

  24. #24 Michael Friedman
    January 10, 2006

    I think a lot more work is needed before this would be convincing.

    Some questions:

    To what extend did self discipline correlate with IQ? Are you really measuring two different things?Any thoughts on the extent to which self discipline is learned vs. innate? If it is learned are you just predicting people’s ability to learn in the next six months based on their ability to learn to date?Tied to that, how closely does self discipline correlate to prior grades? Which of those two is a better predictor of future grades?

    The more I think about this the less convinced I am. If you want to convince me that you are measuring something real I think you need a reasonable chunk of the supporting evidence that has gone into IQ tests – twin studies, etc.

  25. #25 Dave Munger
    January 10, 2006

    Michael,

    IQ did not correlate with self-discipline.

    A lot more research needs to be done to answer the remainder of your questions, but the key here is the point that IQ is almost certainly not the holy grail that many have treated it as.

    Phil, I don’t know the answer to your question. These are all high-achieving kids, and to me that may be the most significant objection to the study. How well does self-discipline lead to achievement when you’re dealing with kids from across the entire spectrum of abilities?

  26. #26 Neil Lynch
    January 10, 2006

    I once saw a ‘humorous’ article explaining (using 4 quadrants) who they would employ. One axis was bright / not bright and the other industrious / not industrious – unfortunalely I have no recollection of author or journal. The quadrants, in preferance order, were:
    1. Bright / industrious
    2. Bright / not industrious (lazy but will think of innovative solutions for achieving with minimal effort)
    3. Not bright / not industrious (causes little harm)
    4. Not bright / industrious (can cause irreparable harm but is not smart enough to know …)

    On a slightly different track, IQ may not be one measure. Howard Gardner (Multiple Intelligences) proposes that people may have varying intelligences that can be measured for:
    * literacy
    * numeracy
    * musical ability
    * kinesethic abilities
    * spatial awareness
    * interpersonal skills
    * intrapersonal skills

    Parts of this are often written about as ‘emotional intelligence’.

  27. #27 Solveig
    April 28, 2006

    Oh for crying out loud, when am I going to see an end to all these articles about how high iq doesn’t matter? Mine is currently 146 (I’m 27) and I was tested several times as a child. I don’t think the same as my contemporaries – FACT – COPE WITH IT. Can we stop all this pandering to the egos of the majority and just admit that some people are more intellectually sharp than others please? It really doesn’t matter – some of us are meant to be rocket scientists, some of us aren’t so can we all just get on with our flamin jobs on this earth please and leave our egos out of it?! It’s all to do with the 85%-odd who have human average IQs of 100 not being comfortable with who they are and their abilities. I’m sick of being the target of bullying crap because of their ego games, I’ve had it all my life and I’m sick of it! The sooner human beings stop competing and start co-operating and accepting themselves and each other the flippin better! I have a job to do in my life, as we all have no matter what our intellect – I’m a “genius”, so what, leave me alone!! I refuse to keep apologising to my fellow man for who I am! Don’t worry – life aint a bowl of cherries being at the top end of the intellectual scale either you know, try being bullied all your life and not being interested in most things your mates are. Being the odd one out – according to Mensa only 3% of people think like me.It’s pretty lonely over here I can tell you, I feel isolated and misunderstood alot of the time. At least most of you lot have got company!!
    So lets get a grip Planet Earth and get on with our jobs!! Ta! xx

  28. #28 Marcus
    May 19, 2006

    Dear Dave,

    thanks for posting this interesting article! I am blessed with a high IQ, but also suffer from ADHD, which means that I often lack self-discipline. This combination yields mixed results, as you might expect…

    Markus

    PS: It seems to me that your graph must be incorrect. The average GPA of all of the students together must be the average of the GPAs of the five quintiles (either on the blue line or on the yellow line). However it looks as if the average of the five yellow dots is not the same as the average of the five blue dots.

  29. #29 Dean Schonfeld
    May 21, 2006

    There is some cross cultural support for the findings of this article. The TIMMS studies measure performance in math across many nations. In looking at same test scores, kids in Asian countries score at the top. Is it a coincidence that Asian cultures praise hard work over IQ?

  30. #30 Siva
    June 6, 2006

    I have an IQ in the range of a gifted person. High IQ is not a boon , rather its acurse. Limited to 100 is good .
    What is needed for sucess is Strong big body, high drive and strong nervous system and social skills. I wish I had a bigger heavily muscled body and 30 points lesser IQ.

  31. #31 Kaethe
    August 3, 2006

    Oh, this was interesting. I’ve been aware for some time that despite studying the hell out of IQ, researchers didn’t find it predictively useful.

    This meshes well with something I’d read not too long ago about how important practice is over the the highly-touted “innate talent.” [I found a similar article archived in the NY Times from 1994.]

    Neil, I think Howard Gardner’s work is interesting, and worthwhile, but IQ is quite definitely one measure, probably most easily defined as pattern recognition.

    Solveig, condescend much?

    some of us are meant to be rocket scientists, some of us aren’t

    The point you seem to have missed is that IQ isn’t predictive of who will become a rocket scientist. Marcus isn’t alone in discovering that high IQ without self-discipline yields mixed results. The non-political appointees at NASA have gotten there by working really hard, regardless of IQs.

    The US is very proud of its meritocracy, and places a great deal of importance upon “innate talent”, of which IQ would be just one. Does anyone happen to know how highly it is valued in other cultures?

  32. #32 James McWilliams
    November 24, 2006

    It’s interesting that Solveig the “genius” rants about people trying to boost their own ego yet his own post reads like nothing more than an exercise in vitriolic self-aggrandizing. It’s like he read the article and became outraged that the unwashed peons could possibly suggest anything that demeans his place up in the ivory towers.
    It would seem to destabilize his delicate superiority complex.

    I guess it demonstrates that high IQ doesn’t stop him thinking much differently from everyone else when it comes to self delusions, insecurity and delicate ego’s.

    I’ve never taken an IQ test, so I have no idea which intelligence bracket I would come under and I don’t really care. Perhaps IQ tests are not quite as regarded over here in the UK as they are in the US?

  33. #33 Joe Shelby
    January 19, 2007

    A comment that came to mind on the “High IQ” post from November that you link to.

    One variable that didn’t seem accounted for is the actual class difficulty level, which is oft related to IQ (or some other test mechanism), regardless of self-discipline. There’s also the variables on GPA from non-academic classes where other non-intellectual parameters get into play like music (an “easy A” for many) and physical education (an unavoidable “C” for anybody with my terribly skinny body type).

    So there’s always that question of the relationship between self-discipline and the level of difficulty of the class itself and how IQ might affect one in affecting the other. I could have taken easy classes and gotten A’s except I got extremely bored very quickly and stopped working ’cause I “already knew it all” and couldn’t maintain the self-discipline through the boredom.

    In short, it kinda ignores the classic “under-achiever” stereotype (like myself and my wife – i fear for our eventual kids) that’s still a common persona in schools.

  34. #34 Thomas Harris
    January 20, 2007

    That “high IQ” rant was hilarious.

    I have a high IQ as well. But really, it’s not that important. There seem to be a lot of sick geniuses out there.

    I think people get way too emotionally charged about this. Grades are not even close to all that matters. There are so many educated fools out there (and so many failed geniuses), it’s downright scary.

    I’d take common sense over genius any day.

  35. #35 Brian
    February 9, 2007

    Hello all,

    A recent set of articles in the Wall Street Journal by Charles Murray (a STRONG proponent of the predictive power of IQ) is discussed extensively on a site you may be interested in: Bravehumans.com. Please come over and check it out if you are so inclined.
    Bravehumans.com

  36. #36 dick chan
    January 1, 2008

    Good.I come from china. I don`t believe the IQ tests are good enough.And I wanna ask you what IQ is?It`s too hard and early to definite.chinese are much more self-discipline.

    On a slightly different track, IQ may not be one measure. people may have varying intelligences that can be measured for:
    * literacy
    * numeracy
    * musical ability
    * kinesethic abilities
    * spatial awareness
    * interpersonal skills
    * intrapersonal skills
    i really think so.

  37. #37 susan
    November 23, 2008

    IQ vs self-discipline? I would put my money on creativity and imagination. With so many children being raised on television, there will soon be a large demand for anyone possessing this qualities.