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:

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.

智商曾經是成百上千的研究者的主題,學者們曾經致力于研究智商和種族,性別,社會經濟狀況,甚至音樂等之間的關系.有關智商和種族關系以及智商遺傳性的討論也非常熱(可能最有名的是 Steven Jay Gould 的<關于人類的誤區>).然而,所有對智商感興趣的研究中,有關智商在學校表現影響方面課題則較少.

Angela Duckworth 和 Martin Seligman估計,有關智商和學業成就關系之間的論文中,只有不到十分之一的文章提到了自身努力.即便如此,這些小比例關于自身努力的研究也只是認為"它對成功有重要影響 ".Walter Mischel 和 colleagues 發現二十世紀八十年代,四歲的孩子延長快樂的能力(比如手上有兩塊餅干會等一會再吃掉他們,而不是先吃掉一塊再說)成為了年后學術研究的對象.而另外一些人則發現了個性和學業成績之間,以及自身努力和大學優秀生之間的關系.很多關于自身努力的研究出現了相互矛盾的結果,或者這要歸罪于自身努力的難以量化. 是否能出現一個更有說服力的證據:自身努力對學校成績的影響大于智商?

為了落實這個一問題, Duckworth 和Seligman對八年級生進行了一項為期兩年的調查,為了更可信,采用了很多自身努力的量化參數,也測試了智商.學業成績,年級以及很多其他在校表現.籍此,他們發現,自身努力比智商更明顯的預言了學生七個月后的表現.

如何得到這個結果的?他們從學年開始就對八年級學生進行調查,使用了五項不同的自身努力量化參數:Eysenck初級沖動數(有關沖動行為的23個問題), 自我控制系數(關于思考,情緒,沖動和表現的十三個問題),兩個問卷由老師和家長評定該孩子的自我修養,還有一個Mischel的自我滿足測試任務.(給孩子們一個裝了1美元的信封,告訴他們可以馬上花掉它或者一個星后用它換2美元).同時也給他們做了智商測定.

學年結束后,孩子們又接受了調查,還拿到了他們的成績單.最后的數據包括各科平均成績,成績彈性度，他們是否通過了己理想高中的錄取,每天花在家庭功課上的時間等等.所有這些除兩個以外都和自身努力有莫大關系,與智商之間的關系卻很少, 成績彈性度與智商及自身努力都有關系,但是并不是根本性的不同,Duckworth 和 Seligman認為,這或許要歸咎于成績測試智商測試很相似.另一個對二者而言沒有什么不同的因素是學校的出勤率.

最后,自身努力和最終平均成績之間67%的吻合度給人留下深刻印象,而與此對應的是,智商僅僅與其有32%的吻合度.從下面的可以明顯看出來.

智商和自身努力都和平均成績有關,但是自身努力是一個相對更加重要的因素,那些自身努力不夠的人比智商略遜的人成績差,當努力的學生取得的成績要高于高智商的學生.就算在一個學年標志性結束后調校了學生等級,很努力的學生也在年終取得了好成績.但是高智商的學生卻表現平平.而且,研究表明智商和努力之間沒有任何直接關系--它們各自獨立.

并不是說這個研究會終結關于智商和遺傳的爭論,這個研究根本沒有涉及自身努力是否可遺傳.相反,自身努力對不同的人來說,能對成功會起到不同的作用.這個研究也只是在一個學校的八年級取得結論而已.或許自身努力在其他的年齡段它會扮演不同的角色,或許對不同的人種也有不同的效果(研究包含了52%的白人,31%黑人,12%亞裔,4%拉丁裔).

或許,剩下最重要的事情是如何教育孩子奮發努力(如果能教育的話).