Lifelong Impact of Early Self-Control · Curiosity about the power of self-control skills, which include conscien-tiousness, self-discipline, and perse-verance, arose from recent

FEATURE ARTICLE

Lifelong Impact of Early Self-ControlChildhood self-discipline predicts adult quality of life.

Terrie E. Moffitt, Richie Poulton, and Avshalom Caspi

W hen we first joined theDunedin Study team inthe 1980s, we had beentaught in our psychol-

ogy Ph.D. training to think in devel-opmental stages: We had learned whatis typical of preschoolers, of teenag-ers, and of older persons. But "typical"failed to describe any of the 1,000 Studyparticipants, who had been physicallyand psychologically examined sincetheir birth in the early 1970s and werenow teenagers. By interviewing tlieseyoung people, we learned to appre-ciate the remarkable variation among

her sweater. A quiet boy recited mul-tiplication tables for fun. The childrenranged remarkably in a quality that wehave devoted much of our science tounderstanding:, self-control.

The capacity for self-control over ourthoughts and actions is a fundamentalhuman faculty. But the inability to makeuse of that capacity can be our great-est personal failure, especially in today'sfast-paced, fast-food world of endlesspossibility, distraction, and temptation.It's no wonder that every self-help litera-ture shelf is cluttered with promises ofgreater self-discipline.

Our 40-year study of 1,000 childrenrevealed that childhood self-control strongly

predicts adult success, in people of highor low intelligence, in rich or poor.

people of the same age. When asked ifhe had ever started a fight and tried tohurt someone, one cheeky boy replied,"Only Catholics—do they count?"When asked if he had ever been introuble with the police, a 13-year-oldboy replied, "Not yet ma'am, but noworries, it's a-coming to me." Asked tocomplete a simple drawing task, a girlstruggled for six minutes, determineddespite severe disabilities. One daringgirl snuck out with a stolen game under

Terrie E. Moffitt and Avshalom Caspi are professorsin the departments of psychology and neurosci-ence, and psychiatry and behavioral science, atDuke University and at the Institute of Psychiatry,King's College, London. Richie Poulton is direc-tor ofthe Dunedin Multidisciplinary Health andDevelopment Research Unit at the Dunedin Schoolof Medicine in Neîv Zealand. Learn more at: http://ivwui.moffittcaspi.com and http://dunedinstudy.otago.ac.nz. Email: [email protected]

People are living longer than ever.To avoid disability, dependency, andpoverty, people focus on their long-termhealth and wealth. Managing retire-ment savings demands incredible fore-sight at the same time that one is daüybombarded by seductive advertising.Delectable, high-calorie foods are onevery comer, even as jobs leave peopleexercising little besides their fingers andminds. Should it be any surprise thatWesterners face an epidemic of obesity?

As more citizens receive more yearsof education, intellectual achievementalone no longer wins the competitionfor good jobs; employers now screengraduates (and their Facebook pages)for signs of conscientiousness and per-severance, or the lack thereof. Theseremarkable historical shifts are en-hancing the value of individual self-control, not only for well-being butalso for survival.

Our home lives aren't much sim-pler. The prevalence of working par-ents requires a delicate balance of ever-shifting roles and priorities. Whentimes get tough at home, divorce isnow a ready and socially acceptableoption—as are a wide range of addic-tive substances, prescription or other-wise. Keeping a family healthy and in-tact requires a tremendous act of will:Parents teach their children to controlthemselves and their emotions alongwith teaching them their ABCs.

Curiosity about the power of self-control skills, which include conscien-tiousness, self-discipline, and perse-verance, arose from recent empiricalobservations that preschool Head Start,an ambitious, federally funded programof special services lamiched in 1965 toboost the intellectual development ofneedy children, has failed to achieve thegoal of boosting IQ scores. But the pro-grams have unexpectedly succeeded inlowering the former pupüs' rates of teenpregnimcy, school dropout, delinquen-cy, and work absenteeism.

IQ was not increased by Head Startbut clearly something else was. A 2006paper in Science by economist and No-bel laureate James Heckman and othersposed the question: Could it be self-control? We recognized on reading itthat we were in a unique position tolearn answers to this question, usingdata from the Dunedin children wehad followed for the past 40 years. Ifself-control is a malleable, teachable de-terminant of success in health, wealth,parenting, and avoiding crime, thenpolicies aiming to enhance it could havebroad benefits. Our quest over the pastfew decades has been to understandwhether childhood self-control affectsadult life chances, and how powerfully.Evidence may convince policy makersthat enhancing self-control can effec-tively reduce major social problems.

352 American Scientist, Volume 101

Better Than a Marshmallow TestWhen we decided to look into self-confrol, we knew we faced skeptics. Infact, we ourselves were skeptical. Manybehavioral scientists believed that self-control problems were a normal partof childhood and quickly outgrown. Iftrue, then childhood self-control wouldhave no implications for adult life. Oth-er scientists conceded that self-controlmay be of mild academic interest, butsaid it could not be as influential foradult life as a child's IQ or social class.Some conceded self-control may beinfluential, but xmworthy of study be-cause it is impossible to change. Stillothers viewed self-confrol as important,but only in the small group of childrendiagnosed with severe attention-deficithyperactivity disorder (ADHD). Weknew we might find that self-controlbore no relation to adult outcomes, orthat its connection to adult Ufe wouldpale to insignificance once IQ and socialclass were added to our analyses. Wehalf expected to find poor adult out-comes resfricted to ADHD children. To

The Dunedin Study is a longitudinal research effort that has followed more than 1,000 peoplefrom birth over four decades, collecting information on their physical health and social well-being. Over the past 38 years, the participants have been physically and psychologically exam-ined 12 times, at birth and then at ages 3, 5, 7,9,11,13,15,18,21,26,32, and 38.

our own surprise, our 40-year studyof 1,000 children revealed that chüd-hood self-control strongly predictsadult success, in people of high or lowinteUigence, in rich or poor, and does sothroughout the entire population, witha step change in health, wealth, and so-cial success at every level of self-confrol.

In the context of intense poUcy inter-est in self-confrol, the longitudinal studythat we had been involved with for de-cades provided invaluable informationabout variation in self-control and weU-being across a population and acrosseach individual's Ufetime. The DunedinMultidiscipUnary Health and Develop-ment Study is a 40-year investigation ofhealth and behavior in just over 1,000individuals born between April 1972and March 1973 in Dunedin, New Zea-land. Tlie study began with babies as anobstetric survey of newborn health but

evolved into a powerful long-term studyof much more, including behavior andpsychology. Assessments of the Studyparticipants were carried out at birthand at ages 3,5,7,9,11,13,15,18,21,26,and 32. Remarkably, between 2011 and2012, 95 percent of the 1,007 stirvivingstudy members, now 38-year-old adiüts,took part in the most recent assessment.For each assessment, study members re-tum to our research center in Dunedin,as they have done aU their Uves, for eighthours of grueling tests, examinations,and interviews about a broad array oftopics related to their health, wealth, andbehavior, including self-confrol.

The Duiiedin Study observes real peo-ple Uving real Uves, so this design lendsitself to analyzing correlations to under-stand behavioral patterns over the par-ticipants' lifetimes. Importantly, Dunedinparticipants with low self-confrol and

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poor outcomes have not dropped out ofthe study, enabling us to explore a fullrange of ufe experiences. Because of thestudy's design, we can address mulfiplepolicy-relevant quesdons: whether self-condol measured at preschool age canpredict outcomes in adulthood; whetherchildren wiüi low self-control are morelikely as teenagers to smoke tobacco,drop out of school, or become teen par-ents; whether children's self-controlconsistently predicts their later health,wealth, criminality, and parenting; andwhat any of it has to do with happiness.

We assessed the Dunedin chüdren'sself-control during their first decade oflife. Eadi child's self-control was ascer-tained in muldple ways: across ages 3,5, 7, 9, and 11, our research staff madeobservational ratings of each child'sbehavior at the research center, teach-ers filled in quesdonnaires sent throughthe mail, parents were interviewed, andat older ages the children themselveswere interviewed. Because these manyratings were strongly correlated, wecombined them into a single, highly re-liable composite self-control measure(see sidebar below, "Wliat Is Self-Control?").All children lack self-condol now cindthen, but this composite measure en-sured that low scorers had shown poorself-control in a variety of situadons andacross years. Mean levels of self-controlwere significantly higher among girls

than among boys, but the impHcadonsof childhood self-control were equallyevident for both sexes. We thereforecombined the sexes in all subsequentanalyses (but controlled stadsdcaUy forthe effects of sex, just to be sure).

It is well known that high family so-cial class and good intelligence influ-ence children's adult life success. We seethis pattem in our study as well: Dune-din children with greater self-controlare significantly more likely to be fromsocioeconomically advantaged fami-lies. Children wiüi greater self-controlalso had significantly higher IQs whentested by the Study in the. 1970s. Thesefindings raised the quesdon of whetherself-control has any effects of its ownon a child's development. We there-fore indoduced stadsdcal controls to allanalyses described here, to test whetherchildhood self-condol predicted adults'health, wealth, parenting style, and like-lihood of commitdng crime, indepen-dent of their social class origins and IQ.

Health and Wealth in DunedinIn our research into the effect of self-control, one of our key goals was toexamine adult health problems becausethese are known early warning signsfor costly age-related diseases and pre-mature mortality. To do this, we con-ducted a thorough assessment of theDunedin children when they reached

their thirdes. Each participant under-went a series of physical examinadonsand laboratory tests to assess obesity,hypertension, and lung damage; weeven had them checked for periodontaldisease. We also tested blood samplesfor high cholesterol, sexually transmit-ted infecdons, and blood proteins indi-cating systemic inflammadon.

We summed these clinical measuresinto a simple physical health indexfor each Study member. Although 43percent had none of the clinical bio-markers, 20 percent had two or morebiomarkers. Childhood self-control sig-nificantly predicted the number of theseadult health problems (See the top graphon the opposite page). We also conductedclinical interviews with the Study mem-bers in their thirdes to assess substancedependence. As adults, children whohad shown poor self-control reportedsignificantly elevated risk of substancedependence, and were addicted to agreater number of substances. Becausepeople may underreport their sub-Stance abuse, we also turned to inde-pendent informants for confirmadon.Each participant nominated someonewho knew him or her well and couldcomplete a survey about his or her lifesituadon. The informeints verified thislongitudinal link between self-controland substance dependence: As adults,children with poor self-control were

What Is Self-Control?Self-control is an umbrella constructthat bridges concepts and measure-ments from different scientific disci-plines, including the variables listedat right. The importance of self-controlis clear. Health researchers report thatself-control predicts early mortality,psychiatric disorders, and unhealthybehaviors, such as overeating, smok-ing, unsafe sex, drunk driving, andnoncompliance with medical regimens.Sociologists find that low self-controlpredicts unemployment, and crimi-nologists name self-control as a centralcausal variable in crime theory, provid-ing evidence that low self-control char-acterizes law-breakers. Tlie underlyingnattire of self-control is still subject toinvestigadon, however.

Neurosciendsts study self-control asan execudve funcdon carried out in thebrain's frontal cortex; MRI studies haveidendfied the brain structures cind sys-tems that are acdvated when research

subjects exert self-control. Behavioralgenedcists haveshown that self-control is subject toboth genetic and en-vironmental influ-ences. In our ownE-risk Twin Study,we found thatgenetically ident-ical twins are moresimilar in self-control at age 5 than arefraternal twins (the twin similarity cor-relations were .68 versus .36, respec-dvely). Geneticists are now searchingfor genes associated with self-control,but our identical twins are far fromidentical on self-control, which pointsto significant nongenetic influences onchildren's self-control. Research by de-velopmental psychologists is uncov-ering how young children learn self-control skills.

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more likely to be rated by informantsas having alcohol and drug problems.

In addition to health problems, weexamined unfavorable outcomes inwealth, such as low income, poor sav-ing habits, credit problems, and socialwelfare dependence—all early warningsigns for late-life poverty. Once again,childhood self-control foreshadowed theStudy members' situations in their thir-ties. People who as chüdren exhibitedpoor self-control were by their thirtiesless likely to have saved money and hadacquired fewer financial buuding blocksfor the future (such as home owner-ship, investment funds, or retirementplans). Children with poor self-controlalso were more Kkely to struggle finan-daUy in adulthood: They reported to usmore money management difficultiesand credit problems. This link betweenself-control and self-reported financialproblems was again verified by infor-mants who knew them weü.

Official administrative records alsoconfirmed that childhood self-controlpredicts adtüt financial outcomes. Forexample, self-control ratings in child-hood foretold our Study members' offi-cial credit ratings in adulthood, ratingsthat can impede attainment of businessloans or home mortgages. A match ofStudy members to the VEDA CreditSystem for Australia and New Zealandrevealed that the lowest self-controlchüdren were most likely to be rated asundesirable credit risks as adults.

With the assistance of the New Zea-land Ministry of Social Development,we further examined costs to govern-ment in the form of social welfare ben-efit dependence, by matching Studymembers to records of monthly sodalwelfare payments. More than half thecohort had at some time received suchbenefit payments. Although most vot-ers want their country to have a safetynet, few approve of iong-term depen-dence on social welfare benefits. Self-control ratings only weakly predictedwhich members of the Dimedin grouphad received a govemment benefit, in-dicating that a broad range of peopleneed help, particularly in today's weakeconomy. However, if they did receive abenefit, those Study members with thepoorest self-control were likely to stayon benefits for a longer period of time.Benefit recipients in the cohort's highestquintile of childhood self-control hadused benefits on average for less than18 months, whereas recipients in thelowest self-control quintile had used

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benefits on average for more than sixyears. Overall, children who had lowerself-control grew up to be adults withmore financial difficulties.

We also examined convictions forcrime, because crime control poses majorcosts to govemment. For example, crimeprevention, control, criminal courts, andincarceration have been estimated to ac-count for 10 percent of the U.S. gross do-mestic product, almost as much as heedthcare. We obtained records of Study mem-bers' court convictions at au courts inNew Zealand and Australia by search-ing the central computer systems of theNew Zealand police; one quarter of ÜieStudy members had been convicted ofa crime by their thirties (comparable toconviction rates in other developed na-tions). Children with poor self-controlwere more likely to have been convictedof a criminal offense. Among the 5 per-cent of the cohort who had spent timeincarcerated, more than 80 percent camefiom the cohort's two lowest quintiles ofchüdhood self-control.

The Dunedin Study let us examinethe effects of self-control on not only theStudy participants but also their chil-dren. The first Dunedin Study mem-ber became a parent in 1988 at age 15,and by 2012, three quarters of the 1,037members were parents. When the firstchild of each member reaches age 3,our research team visits the family athome to record parent-chüd interactionduring a standardized set of activities.Family psychologists blind to all otherinformation about the Study rate vid-eos on aspects of parenting, includingaffection and sensitivity to their chüd'sneeds. On an overaü combined ratingof parenting quality. Study memberswho as chüdren had poor self-controlgrew up to be the least skiüed parentsof their own chüdren. Childhood self-control also strongly predicted whetherthese members' offspring were in a two-parent or a one-parent household. One-parent households were more likely

Children who showed early difficulty withself-control grew up to have poorer health,greater substance abuse, more financial dif-ficulties, higher crime conviction rates, andlower parenting skill, even after controllingfor the effects of IQ, social class, and sex.Health and substance abuse were both stan-dardized into z-scores: negative scores arebelow average, and positive scores are aboveaverage. (Unless otherwise noted, all graphsadapted from Moffitt, T. E., et al. Proceedingsof the National Academy of Sciences of theIÍ.S.A. doi:10.1073/pnas.l010076108.)


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Children who avoided mistakes in adoles-cence, such as smoking, dropping out ofschool, or teen parenthood, grew up to beadults with better health, greater wealth,and lower crime conviction than those withsimilar self-control levels who did not avoidthese pitfalls. This finding indicates that pre-venting such adolescent mistakes could havelifelong benefits. Adult wealth and healthare normalized around a mean of 0.

for adults that had low self-control aschildren. These findings imply that onegeneration's low self-control causes dis-advantages to the next generation.

In summary, boys and girls withweaker self-control had worse health,less wealth, less skuled parenting, andmore crime as adults than those withstronger self-control, and that patternheld at every point along the gradi-ent of self-control. To check that ourobserved correlation was robust, werepeated the analyses after removingchildren in the least and most self-controlled quintiles. We continued toobserve significant linear associations,indicating that the findings did not de-pend on an extreme group.

Psychiatrists asked us if the societalchallenge of self-control could be ame-liorated simply by treating childhoodADHD. To investigate, we removed the61 members who were diagnosed withADHD and repeated the analyses. Thegradient associations remained unal-tered. These results, coupled with thepersistent effects of self-control after ac-counting for variation in sex, social classorigins, and IQ, suggest that teachingself-control skiüs, if they can be taught,would benefit even children who scoreabove average on self control, are intel-Ugent, or come from affluent homes.

When Do Troublemakers Start?The strengtli of otir observed correlationsbetween childhood self-control and adultquality of life made us wonder whenand how that correlation emerges. Ourcomposite measure of self-control in theDunedin Study included assessmentsfiom mulfiple reporters, covering ages3 to 11. To answer oxir question, we iso-lated our research staff ratings of self-control made when the children were3-5 years old in the mid-1970s. This mea-sure is a weaker one because in thoseearly years we had only a stranger'sobservations from a 90-minute meet-ing with the dtild at our research center.Nevertheless, that brief observation ofpreschoolers' self-control significantlypredicted outcomes in the fourth de-cade of Ufe, although less well than ourmore extensive measure that includedparent and teacher opinions collectedover the years from ages 3 to 11.

Early warning signs of troubled adult-hood often arise in adolescence, but wewere not sure if interventions address-ing self-control at this life stage wouldbe effective in preventing imdesirableUfe outcomes. Data coUected at ages 13,15,18, and 21 showed that children withpoor self-control were more likely tomake mistakes as adolescents. For ex2im-ple, more diildren with low self-controlbegan smoking by age 15, left second-ary school early with no educationalqualifications, and became unplannedteenaged parents. The lower their self-control as children, the more ensnaredthey were as teens; and the more snaresthey encountered, the more Ukely theywere to have poor health, less wealth,unskilled parenting^ and a criminal con-viction record 20 years later.

We also tested the association betweenchildhood self-control and the adultoutcomes among adolescents who en-countered no snares, a so-caUed Utopian

group of nonsmoking, non-teen-parent,secondary-school graduates. Comparedwith the fuU cohort, this Utopian sub-set had befter health, wealth, and crimehistory, illustrating that preventingadolescent mistakes can enhance adultoutcomes for children at any level ofself-control. This comparison of adultoutcomes for teens who did versus didnot make mistakes hints at what suc-cessful intervention might accompUsh.However, prediction from childhoodself-control to the adult measures re-mained significant along a gradient, evenamong the Utopian group. Helping teensavoid snares could improve populationhealth, wealth, chud welfare, and pub-lic safety somewhat, but building self-control skOls before the teen years is alsowarranted.

PoUcy making requires evidence thatisolates self-control as an active ingredi-ent in health, wealth, and crime, beyondintelligence or social class origins. Inthe Dunedin Study, statistical controlsconsistently reveal that self-control hasan independent eftect on Ufe outcomes.However, each Study member grew upin a difterent family, and their familiesvaried in many other ways that influencechildren's Ufe outcomes, making it trickyto know whether self-control was moreimportant than unmeasured variables.

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Fraternal twins of the same sex and growingup in the same household differ in their self-control levels. Self-control at age 5 forecastsoutcomes seen by age 12, even after control-ling for differences in IQ. For example, thetwin with poorer self-control was more likelyto begin smoking by age 12 than the twinthat had more self-control at age 5. Again,values were standardized so that the mean isrepresented by 0.


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Children that exhibit greater self-controlgrow up to be adults that express more sat-isfaction in their lives, a pattem that holdsafter controlling for the effects of IQ, socialclass, and sex.

Twin ComparisonsFor an acid test of self-control as anactive ingredient, we took advan-tage of an independent study, theEnvironmental-Risk Longitudinal TwinStudy (E-risk), a British birth cohortof 2,232 twin siblings whom we havetracked since their birth between 1994and 1995, with 96 percent retention. Wedesigned the E-risk Study to replicatethe Dunedin Study, this time with theadvantage of two chudren per family.

Twins do not have identical levels ofself-control, but they do grow up in thesame family, which gave us the oppor-tunity to ask whether the sibling in eachtwin pair who had lower self-controllater developed worse outcomes. Thiscompelling quasi-experimental re-search design isolates the influence ofself-control by tracking and comparingsiblings, disentangling the individualchild's self-control from all other fea-tures on which families differ. We ana-lyzed self-control differences within 509same->sex fraternal twin pairs, because,unlike identical twins, fraternal twinsare no more alike as children than ordi-nary siblings on their self-control levels.

When the E-Risk twins were fiveyears old, our research staff rated eachchild on the same measure of self-control we had used when the Dunedinchildren were preschoolers. Althoughthe E-risk children had been followedup only to age 12 when we performedanalyses for this article, their age-5 self-control already forecasted many of theoutcomes we saw in Üie Dunedin Study.Our analysis showed that the 5-year-old sibUng with poorer self-control was

sigrdficanfly more likely as a 12-year-oldto begin smoking (a precursor of pooradult health), perform poorly in sciiool(a precursor of adiüt poverty), and en-gage in antisocial conduct problemssuch as steaUng and fighting (a precur-sor of adult crime). (See the chart at thebottom ofthe opposite page.)

Another provocative finding fromthe E-Risk study attests to the societalcost of low self-control. Tlie twin withlower self-control was rated by teach-ers as requiring more of their effort inthe classroom. Results showed thatchildren with low self-control depleteteachers' energy for teaching other pu-pils. Children lacking in self-controlmay even contribute to teachers' jobdissatisfaction and attrition.

Reengineering the SelfOur results from the Dunedin Studyshow that individual differences inchildhood self-control have key socialeffects. They predict multiple indica-tors of health, wealth, parenting, andcrime across three decades of Hfe, in bothsexes. Furthermore, the E-risk Studycomparison of fraternal twins helpedus disentangle the effects of chüdren'sself-control from the effects of variationin their social class and home Uves, sin-gUng out seU-control as a clear target forintervention poUcy.

But are children with self-controlhappy? Some may express concern thatchudren with the highest levels of self-control must be rigid, unspontaneous,and unhappy. They fear that interven-tions may reduce happiness. Promptedby this concern, we exarrdiied indicatorsof our Study members' life satisfactionin the fourth decade of Ufe. Fortunately,most cohort members said they weresatisfied with their Uves: 70 percent weresomewhat or very satisfied. However,the most satisfied of aU were those whobegan life with high self-control (nearly90 percent of them felt satisfied). Highself-control protected Dunedin Studymembers from suicide, an objective in-dicator of deep unhappiness. Of partici-pants in the bottom fifth of self-controlscorers, 22 percent attempted or diedby suidde by age 38, but only 7 percentin the top fifth of chudhood self-controlscorers made a suicide attempt.

Joining earlier longitudinal follow-up studies, our findings imply tliat in-novative policies that put self-controlcenter stage could reduce a panoply ofcosts tliat now heavüy burden taxpayersand governments: health care deUvery,

crime control, sodal welfare, and educa-tion. Moreover, many Dunedin Studymembers with low self-control had un-planned babies who are now growingup in a low-income single-parent house-hold lacking in skuled parenting, wherethe parent is substance-dependent, inpoor health, or overcoming a criminalrecord. Therefore, one of the highestcosts of seU-control may be the poor startit creates for successive generations.

Improving childhood self-control isespecially appealing because we findthat differences in self-control betweenchudren predict their adult outcomesapproximately as well as (sometimesbetter than) low intelligence and lowsocial class origins, factors known to beextremely difficult to improve throughintervention. Effects were marked atthe extremes of the self-control gradi-ent. For example, by adulthood thosewith the highest and lowest chüdhoodself-control were at opposite ends of thespectrum in adult outcomes. For Studyparticipants in the top fifth of child-hood seU-control scores, only 10 percentmade an annual income below the pov-erty line, as opposed to the 32 percent ofadults who as chudren had scored in thebottom fifth on self-control measures.

1 2 3IQ, chiidhood(2-score)

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self-controi, childhood(z-score)

Childhood IQ is tightly correlated with adultIQ; in contrast, childhood self-control is signfi-cantly correlated with adult self-control butshows much more room for change. The factthat a child with low self-control can still be-come an adult with high self-control indicatesthat self-control may be a more malleable andteachable characteristic than IQ. Scores arenormalized around a mean of 0.


In Sesame Streets multimedia activity "For me. For you. For later,"an intervention targeting earlychildhood self-control, Elmo learns to save money for an intriguing toy. (http:llsesamestreet.org/parentsltopicsandactivitiesltootkitslsave; photograph courtesy of Richard Termine.)

Simüarly, the top fifth exhibited crime-conviction rates of 13 percent as op-posed to 43 percent for the bottom fifth.

After estabUshing the sfrong relation-ship between childhood self-controland adult well-being, we stiU were notsure what, if anything, could be doneto help those with weak self-control.Many potential interventions seemedpromising, so we began to look intotheir effectiveness. Possible interven-tions run the age gamut, targeting pre-school children to adults, and interven-tions approach the self-control deficitat many levels, from one-on-one skilltraining to federal legislation.Importantly, analyses led byBrent Roberts of the Universityof Illinois attest that self-confrolcan change. In fact, in the Dune-din Study, across the first fourdecades of Ufe, study members'self-control scores were onlyabout half as stable as their IQtest scores {See the graphs at thebottom of page 357). We foundone factor that improved somemembers' self-control rank:working as a supervisor respon-sible for subordinate employees.Of course, those who becamemanagers already had good self-control, one likely reason thatthey were hired or promoted.However, even after becomingbosses, their self-control scoresrose rapidly compared withscores of their cohort peers.

In our studies, health, wealth, andcrime outcomes followed a gradientacross the full distribution of self-confrol in the population. The observedgradient implies that better outcomesare possible and suggests universalinterventions. Such programs benefiteveryone, avoid stigmatizing anyone,and tberefore attract widespread citi-zen support. An example of a universalintervention is Sesame Street's multi-media activity "For me. For you. Forlater," which teaches preschoolers todelay gratification by saving moneytoward a goal.

programs targeted toward the earliest years

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age

James Heckman asserts that at current levels of funding,government underinvests in preschool education, given thelifelong retum on investment. (Figure adapted from Heck-man, J. Science 312:1900.)

Programs to enhance young chil-dren's self-control have been devel-oped, and many show promise. Suchself-control enhancers for children in-clude martial arts, music lessons, andcomputer games. Even mastering asecond language develops self-confrol.There are programs for school class-rooms, based on the notion of "plan,do, then review." Some programs tar-get parents, coaching them on how toraise their chüd's self-confrol quotient.The chaUenge remains to improve theseprograms and scale them up for uni-versal dissemination with a good cost-benefit ratio. Many programs show po-tential as small model demonsfrationsdeUvered to keen voltinteer farrdUes byenthusiastic experts. But these prom-ising schemes must work just as wellwhen fransferred to a statewide schoolsystem and implemented by nonprofes-sional staff. Randomized friáis shouldshow that the programs produce realchange in self-confrol skills, and long-term follow-ups need to show that thechange is lasting. Economic analysesmust weigh whether the up-front costsof each program are outweighed bytheir eventual effect on costs of healthcare, crime, and financial dependency.

Our findings support a "one-twopunch" strategy of scheduling inter-ventions during both early childhoodand adolescence. On the one hand, theconnection between low self-controland poor outcomes from childhoodto adulthood was in part a function ofmistakes made in adolescence. There-fore, interventions that prevent teen-

agers' mistakes may improvehealth, wealth, child welfare,and pubUc safety for the popu-lation. On the other hand, be-cause childhood self-controlpredicts which teens wül rnakelife-altering mistakes, early-childhood intervention couldprevent teens from making suchmistakes in the first place. Evenamong teens who managed tofinish high school as nonsmok-ers and nonparents, the level ofpersonal self-control they hadachieved as children explainedsubstantial variation in theirhealth, finances, and crime rateswhen they reached their thirties.Consequently, enhancing self-confrol in early childhood willlikely bring a greater retum oninvestment than waiting untiladolescence.


Even in adulthood, there may bemeaningful ways to improve self-control. Social psychologists havemarshaled experimental evidence thatself-condol is like a muscle: Adults canexercise and sdengthen it, but their self-condol can also be depleted when theyare stressed, intoxicated, or fatigued.In a culture in which low self-controlreigns, policy makers have tended torespond with schemes that make social-ly responsible behaviors, such as eadnghealthfully, saving money, or obeyingthe law, the effort-free default opdon.For example, the crime-reducdon pol-icy called "target hardening" discour-ages would-be offenders by makinglaw-breaking so onerous that it losesits easy-money appeal (A case in point

we hope, accept our invitadons to takepart in each burdensome, intrusive newwave of data coUecdon.

In longitudinal research Hke this, wescientists design measurements to re-cord the most important biological andsocial developments at each stage of Ufe.When the pardcipants were babies, otirteam had to be expert on quesdons ofbirth weight, breastfeeding, infant sleep,and language development. Now, weare launching invesdgadons into inferdl-ity, retirement savings, parenting, andtelomere erosion. At the same time, weassess certain parameters of health andmental ability, as well as self-condol, atevery age to maintain continuity.

The interplay of genes and environ-ment is a parficularly rich new theme of

The segment of the adult populationmost inclined to avoid effortful planning is

the same segment that accounts for themost costs to society

is sophisticated antitheft devices intoday's cars demand more advancepreparadon and diligence of would-becar thieves). Similarly, because a defaultautomadc payroU-deducdon redrementsavings scheme requires no effort, moreemployees save successfully withouttrying. Such plans assume that just anudge can compensate for imperfectself-condol.

Our research demonsdates that thesegment of the adult populadon mostinclined to avoid effortful planning isthe same segment of the adult popula-don that accounts for the most coststo society. So-called nudge policies in-tended to exploit the laziness in all ofus should work best for the least self-condolled among us, significantly mag-nifying their benefits. Ultimately, whenall hope is lost that adults will condolthemselves in response to a nudge, na-dons resort to passing coercive laws toenforce self-control, such as banningsmoking in public places and makingmotorcycle helmets, seatbelts, and in-fant car seats obligatory.

Maturing and Reproducing StudiesBoth the Dunedin and E-risk studiesare long-term research projects that willcontinue to improve our understandingof self-condol. The study members con-tinue to grow up and grow older, and.

our research. Untu now, neuroimaginghas been conspicuously missing fromthe Dunedin Study's treasure troveof measurements. We are preparingto study variation in the structure ofStudy members' brains, as well as di-rect fMRI studies of how their brainsprocess threat, reward, memories, andthe execudve funcdons of self-control.Our U.S.-New Zealand-U.K. teamis already planning investigations ofmembers' experiences of menopause,memory loss, grandparenting, andeventually redrement. The Study mem-bers' great gift to science is their lifelongcollaboradon in this work.

Globally, the human population istrending toward fewer children andmore elderly people. If this trendcontinues as predicted, soon youngworkers will be obliged to support alarger number of redred seniors. In thecoming century the value that soci-ety places oh every child will increase,along with expectadons that each mustcontribute maximally toward his orher nation's health, wealth, and publicsafety. Simultaneously, the trend to-ward longer life expectaiicy means thattoday's children must prepare strategi-cally while still young to secure well-being in their own prodacted old age.These historic demographic changesare driving up the value of individual

self-control. The two cohorts we arestudying—born in different coimtriesand different decades—strongly sup-port that improving individual self-condol will prove essendal for human-ity's long-term health, wealth, safety,and happiness.

BibliographyBaumeister, R. F., and J. Hemey. 2011. Willpower:

Rediscovering the Greatest Human Strength.New York: Penguin.

Casey, B. J., et al. 2011. Behavioral and neural cor-relates of delay of gratification 40 years later.Pmceedings ofthe National Academy of Sciences oftte ¡J.S.A. 108:14998-15003.

Center on the Developing Child at Harvard University.2011. Building the Brain's "Air Traffic Control"System: How Early Experiences Shape the De-velopment of Executive Function: Working PaperNo. 11. http://www.developingduld.harvard.edu, downloaded April 2,2013.

Diamond, A. 2011. Interventions shown to aidexecutive function development in children 4to 12 years old. Sdaice 333:959-964.

Heckman, J. J. 2006. Skill formation and the eco-nomics of investing in disadvantaged chil-dren. Science 312:1900-1902.

Kern, M., and H. Friedman. 2008. Do conscien-tious individuals uve longer? A quantitativereview. Health Psychology 27:505-512.

Knudsen, E. I., J. J. Heckman, J. L. Cameron, andJ. P. Shonkoff. 2006. Economic, neurobiologi-cal, and behavioral perspectives on buildingAmerica's future workforce. Proceedings ofthe National Academy of Sciences of the U.S.A.103:10155-10162.

Kochanska, G., K. C. Coy, and K. T. Murray2001. The development of self-regulation inthe first four years of Hfe. Child Development72:1091-1111:

Mischel, W., Y. Shoda, and M. Rodriguez. 1989.Delay of gratification in children. Science244:933-938.

Moffitt, T. E., et al. 2011. A gradient of chiidhoodself-control predicts health, wealth, and publicsafety. Proceedings of the National Academy ofSciences ofthe U.S.A. 108:2693-2698.

Piquero, A. R., W. G. Jennings, and D. P. Far-rington. 2010. On the malleability of self-control: Theoretical and policy implicationsregarding a general theory of crime. JusticeQi/flrter/y 27:803-834.

Roberts, B. W., K. E. Walton, and W. Viechtbauer.2006. Patterns of mean-level change in per-sonality traits across the Hfe course: A meta-analysis of longitudinal studies. PsycliologicalBulletin 132:1-25.

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Lifelong Impact of Early Self-Control · Curiosity about the power of self-control skills, which include conscien-tiousness, self-discipline, and perse-verance, arose from recent