Are Adolescents Less Mature Than Adults? PDF

Are Adolescents Less Mature Than Adults? Minors’ Access to Abortion, the Juvenile Death Penalty, and the Alleged APA “Flip-Flop” Laurence Steinberg Temple University...

Are Adolescents Less Mature Than Adults? Minors’ Access to Abortion, the Juvenile Death Penalty, and the Alleged APA “Flip-Flop” Laurence Steinberg Temple University Elizabeth Cauffman University of California, Irvine Jennifer Woolard Georgetown University Sandra Graham University of California, Los Angeles Marie Banich University of Colorado The American Psychological Association’s (APA’s) stance (APA, 2004) and was informed by a recent summary of on the psychological maturity of adolescents has been relevant research on psychological development during criticized as inconsistent. In its Supreme Court amicus adolescence that was published in this journal (Steinberg & brief in Roper v. Simmons (2005), which abolished the Scott, 2003). Writing for the majority, Justice Anthony juvenile death penalty, APA described adolescents as de- Kennedy drew attention to three specific aspects of adoles- velopmentally immature. In its amicus brief in Hodgson v. cents’ immaturity that diminished their criminal culpabil- Minnesota (1990), however, which upheld adolescents’ ity: their underdeveloped sense of responsibility (and dif- right to seek an abortion without parental involvement, ficulty controlling their impulses), their heightened APA argued that adolescents are as mature as adults. The vulnerability to peer pressure, and the unformed nature of authors present evidence that adolescents demonstrate their characters. As Justice Kennedy wrote, adult levels of cognitive capability earlier than they evince emotional and social maturity. On the basis of this re- First, as any parent knows and as the scientific and sociological search, the authors argue that it is entirely reasonable to studies respondent and his amici cite tend to confirm, “[a] lack of maturity and an underdeveloped sense of responsibility are found assert that adolescents possess the necessary skills to make in youth more often than in adults and are more understandable an informed choice about terminating a pregnancy but are among the young. These qualities often result in impetuous and nevertheless less mature than adults in ways that mitigate ill-considered actions and decisions.”... The second area of criminal responsibility. The notion that a single line can be difference is that juveniles are more vulnerable or susceptible to drawn between adolescence and adulthood for different negative influences and outside pressures, including peer pres- purposes under the law is at odds with developmental sure.... The third broad difference is that the character of a science. Drawing age boundaries on the basis of develop- juvenile is not as well formed as that of an adult. The personality mental research cannot be done sensibly without a careful traits of juveniles are more transitory, less fixed.... These dif- and nuanced consideration of the particular demands ferences render suspect any conclusion that a juvenile falls among placed on the individual for “adult-like” maturity in dif- the worst offenders. (Roper v. Simmons, 2005, pp. 15–16) ferent domains of functioning. The position taken by APA in its brief—that adoles- Keywords: adolescents, abortion, juvenile death penalty, cents are inherently less blameworthy than adults as a Supreme Court, APA consequence of their developmental immaturity—was I noteworthy not only because it proved so influential to the n its landmark 2005 decision abolishing the juvenile Court’s decision but because it appeared, on its face, to death penalty (Roper v. Simmons, 2005), the U.S. Su- contradict a stance taken by APA in a previous U.S. Su- preme Court held that the inherent immaturity of ado- lescents relative to adults mitigated teenagers’ criminal Editor’s note. June P. Tangney served as the action editor for this article. responsibility to the extent that it barred the imposition of capital punishment for crimes committed under the age of Author’s note. Laurence Steinberg, Department of Psychology, Temple 18, regardless of their heinousness. Prior to this decision, in University; Elizabeth Cauffman, Department of Psychology and Social the United States, individuals could be executed for capital Behavior, University of California, Irvine; Jennifer Woolard, Department crimes committed at the age of 16 or older. By a 5-to-4 of Psychology, Georgetown University; Sandra Graham, Psychological vote, the Court ruled that this age boundary should be set at Studies in Education, University of California, Los Angeles; Marie 18, rather than 16. Banich, Departments of Psychology and Psychiatry, University of Colo- rado. Developmental science was front and center in the Correspondence concerning this article should be addressed to Lau- Court’s ruling, which drew extensively on an amicus curiae rence Steinberg, Department of Psychology, Temple University, Philadel- brief submitted by the American Psychological Association phia, PA 19122. E-mail: [email protected] October 2009 American Psychologist 583 © 2009 American Psychological Association 0003-066X/09/$12.00 Vol. 64, No. 7, 583–594 DOI: 10.1037/a0014763  Ultimately, Simmons wants the Court to declare that [drawing the age boundary for purposes of death penalty eligibility at 16] is now “without penological justification” not based on research that uniformly reaches that conclusion, but based on inconsistent research, viewed through the lense [sic] of a stereotype that the American Psychological Association decried in Hodgson: “[T]he assumption that adolescents as a group are less able than adults to understand, reason and make decisions about intellectual and social dilemmas is not supported by contemporary psychological theory and research.” (Roper, 2004, p. 11) Concerns about reconciling the scientific arguments offered in the two cases were also raised by abortion rights advocates, but in a different context. Indeed, after Laurence Steinberg met with the Executive Committee of the Society for Research on Adolescence, asking for the organization’s endorsement of the APA stance in Roper, the committee decided not to sign on to the APA brief, fearing that the argument that adolescents were not as mature as adults (and thus ineligible for capital punishment) would come back to haunt those who had worked so hard to secure the abortion Laurence rights of young women. As it turns out, these worries were Steinberg not unfounded. Within two years of the Roper decision, the U.S. Supreme Court heard Ayotte v. Planned Parenthood of Northern New England (2006), which, like Hodgson, con- cerned minors’ access to abortion without parental involve- preme Court case, Hodgson v. Minnesota (1990). In that ment. Opponents of adolescents’ autonomous abortion case, which concerned a minor’s right to obtain an abortion rights had taken the Court’s characterization of adolescent without parental notification, APA had argued that because immaturity in the juvenile death penalty case and used it to adolescents had decision-making skills comparable to those argue in favor of parental involvement requirements. Citing of adults, there was no reason to require teenagers to notify the Roper decision, they argued, their parents before terminating a pregnancy (APA, 1987, 1989). Thus, in Roper, APA argued that science showed Parental involvement is critical to ensure not only that the ado- that adolescents were not as mature as adults, whereas in lescent’s choice is informed, but that it is freely made and not the Hodgson, it argued that the science showed that they were. result of coercion or duress.... These concerns are heightened for adolescents who, as this Court has recently observed, are more The apparent contradiction in these views did not go susceptible than adults to “outside pressure” and other “negative unnoticed. Justice Kennedy explicitly asked at oral argu- influences,” and more likely than adults to make decisions that are ment in Roper if the APA had “flip-flopped” between 1989 “impetuous and ill-considered.” Roper v. Simmons, 125 S.Ct. (when its final amicus brief was filed in the abortion case) 1183, 1195 (2005). (Ayotte v. Planned Parenthood of Northern and 2004 (when its brief was filed in the juvenile death New England, 2006, p. 15) penalty case). The flip-flop issue also was raised by those who disagreed with the Court’s decision to abolish the It is easy to see why many criticized the APA for its juvenile death penalty. Indeed, in his dissenting opinion in apparently contradictory positions. On the face of it, the Roper v. Simmons (2005), Justice Antonin Scalia drew APA position in the juvenile death penalty case was in unambiguous attention to this issue: direct opposition to the stance it took in Hodgson. In its amicus brief arguing for adolescents’ abortion rights, for [T]he American Psychological Association (APA), which claims example, APA stated, in this case that scientific evidence shows persons under 18 lack the ability to take moral responsibility for their decisions, has [B]y age 14 most adolescents have developed adult-like intellec- previously taken precisely the opposite position before this very tual and social capacities [italics added] including specific abil- Court. In its brief in Hodgson v. Minnesota, 497 U. S. 417 (1990), ities outlined in the law as necessary for understanding treatment the APA found a “rich body of research” showing that juveniles alternatives, considering risks and benefits, and giving legally com- are mature enough to decide whether to obtain an abortion with- petent consent. (APA, 1989, p. 20) out parental involvement.... The APA brief, citing psychology However, in its amicus brief arguing against the juvenile treatises and studies too numerous to list here, asserted: “[B]y death penalty, APA stated, middle adolescence (age 14 –15) young people develop abilities similar to adults in reasoning about moral dilemmas, understand- Given that 16- and 17-year-olds as a group are less mature ing social rules and laws, [and] reasoning about interpersonal developmentally than adults [italics added], imposing capital pun- relationships and interpersonal problems.” (Justice Scalia, dis- ishment on such adolescents does not serve the judicially recog- senting, pp. 11–12) nized purposes of the sanction. (APA, 2004, p. 13) The petitioner in Roper, the State of Missouri, made a APA responded to accusations that developmental similar point in its brief: psychologists were trying to have their scientific cake and 584 October 2009 American Psychologist  The juvenile death penalty case was an 8th Amend- ment case involving the amendment’s cruel and unusual punishments clause. A central issue in Roper was whether adolescents were mature enough to be held to adult levels of criminal blameworthiness and, in particular, to a level of blameworthiness that potentially warranted capital punish- ment; if they were not, the juvenile death penalty was excessively cruel. Under a bedrock principle of American criminal law known as “penal proportionality,” the punish- ment a guilty party receives should be in proportion to his or her culpability for the criminal act, and certain factors are accepted as mitigating the actor’s culpability. These mitigating factors include diminished decision-making ca- pability (e.g., decision making that is impulsive or short- sighted), exposure to coercion, and evidence of the offend- er’s otherwise good character (Steinberg & Scott, 2003). As noted earlier, the Court ruled that the inherent immatu- rity of adolescents, with respect to the impetuousness of their decision making, their susceptibility to coercion, and their unformed characters, made them categorically less Elizabeth blameworthy than the average criminal and therefore not Cauffman eligible for a punishment that was reserved for only the most culpable offenders. Whether APA in fact “flip-flopped” or, worse yet, tried to have it both ways, as its critics have contended, is eat it too—spinning the science for the sake of youth an exceedingly important question, both with respect to the advocacy— by pointing out that the type of decision under decisions about where to draw legal boundaries between consideration in Roper was not the same as that at issue in adolescents and adults for various purposes and with re- Hodgson: spect to APA’s scientific credibility more generally. As some of us have written elsewhere, “scientists’ authority to We [APA] took note of the Hodgson brief in the approval process for APA’s brief in [Roper] but concluded that the two cases were enter the policy arena rests largely on the credibility of their distinguishable in several respects. [Roper] and Hodgson, while research findings” (Grisso & Steinberg, 2005, p. 620). If both dealing with adolescent decision-making, involved very dif- APA’s statements about the state of scientific knowledge ferent legal issues and different types of decisions. Therefore the are seen as advocacy masquerading as research, the integ- research, which was different in each of the two cases, addressed rity of the Association’s scientific mission is threatened. distinct aspects of adolescent behavior and attributes. (Gilfoyle, After all, in both Hodgson and Roper, APA took a position 2005, p. 1) that could be fairly characterized as, at the very least, There is no question that the legal issues in Hodgson friendly to youth advocates. It is crucial, therefore, to and Roper differed. The abortion rights case was a 14th examine the issue empirically. That is the focus of the Amendment case involving the amendment’s due process present article. clause. The central question considered in Hodgson was For the past several years, as members of the whether the state had a compelling interest in mandating MacArthur Foundation Research Network on Adolescent that an adolescent seeking an abortion be required to first Development and Juvenile Justice, we have been studying notify both her parents. Several legal issues were relevant, age differences in many of the cognitive and psychosocial including whether the notification requirement placed an capacities that have been at issue in the Supreme Court undue burden on adolescents (especially those whose par- cases discussed above. We have been studying basic intel- ents were divorced or estranged) and whether providing for lectual abilities, such as working memory and verbal flu- a judicial hearing as an alternative to parental notification ency, but also aspects of psychosocial development, includ- (known as a “judicial bypass”) was acceptable, but the ing impulse control (Steinberg et al., 2008), future most relevant for the present discussion concerned the orientation (Steinberg et al., 2009), reward sensitivity competence of adolescents to make informed and sound (Cauffman et al., in press), sensation seeking (Steinberg et health care decisions on their own. If it could be concluded al., 2008), and susceptibility to peer influence (Steinberg & that adolescents were sufficiently competent to make an Monahan, 2007). To our knowledge, ours is the first study informed decision about whether to terminate a pregnancy, to include both cognitive and psychosocial measures ad- the state’s interest in requiring parental notification would ministered to the same sample, to include an ethnically and be rendered less compelling. Ultimately, the Court ruled socioeconomically diverse group of individuals, and to that requiring parental notification was constitutional so span the period from preadolescence through young adult- long as a bypass provision was part of the law. hood. October 2009 American Psychologist 585  has an opportunity to consult with an adult expert, whereas the circumstances leading up to the typical adolescent criminal offense—robbing a convenience store, for in- stance—are characterized by heightened emotional arousal, time pressure, and peer influence. For example, studies indicate that about half of all pregnant adolescents contemplating an abortion whose par- ents are unaware of the situation consult with a nonparental adult other than medical staff (e.g., a teacher, school coun- selor, clergyperson, older relative, or adult friend of the family); this figure is the same among younger (under age 16) and older adolescents (Henshaw & Kost, 1992). More- over, 35 states require all women seeking an abortion to receive some type of counseling from the abortion provider before the procedure is performed, usually including infor- mation about the specific procedure as well as the health risks of abortion and pregnancy (Guttmacher Institute, 2009). Twenty-four states mandate a waiting period of at least 24 hours between the counseling and the medical procedure (Guttmacher Institute, 2009). Thus, it does not Jennifer appear as if a high proportion of pregnant teenagers decide Woolard to terminate a pregnancy under circumstances that are rushed or in the absence of adult advice. In contrast, studies indicate that adolescents’ crimes are more often than not impulsive and unplanned (Farrington, 2003) and typically On the basis of this work, some of which we summa- committed with peers (Reiss & Farrington, 1991). Thus, rize in the pages that follow, we believe that APA’s seem- while some of the capabilities relevant to both decision- ingly contradictory positions in Hodgson and Roper are in making contexts no doubt overlap, the circumstances that fact quite compatible with research on age differences in define “mature” behavior in each are clearly different. cognitive and psychosocial capacities. More specifically, Resisting peer influence, thinking before making a deci- our findings, as well as those of other researchers, suggest sion, and considering the future consequences of one’s that whereas adolescents and adults perform comparably on actions are clearly more important in criminal decision cognitive tests measuring the sorts of cognitive abilities making than abortion decision making, in part because that were referred to in the Hodgson brief—abilities that society structures the latter context to promote consultation permit logical reasoning about moral, social, and interper- with adults and avoid hasty decision making. sonal matters—adolescents and adults are not of equal The importance of maintaining a distinction between maturity with respect to the psychosocial capacities listed cognitive and psychosocial maturity in discussions of the by Justice Kennedy in the majority opinion in Roper— legal status of adolescents is supported by other research capacities such as impulse control and resistance to peer that has examined age differences in each of these domains. influence. Not only were the legal issues different in the Studies that have examined logical reasoning abilities in two cases, but so are the circumstances surrounding abor- structured situations and basic information-processing tion decisions and criminal behavior, and therefore, the skills, for instance, have found no appreciable differences relevant dimensions along which adolescents and adults between adolescents age 16 and older and adults; any gains should be compared differ as well. Unlike adolescents’ that take place in these domains during adolescence occur decisions to commit crimes, which are usually rash and very early in the adolescent decade, and improvements made in the presence of peers, adolescents’ decisions about after this age are very small (Hale, 1990; Kail, 1997; terminating a pregnancy can be made in an unhurried Keating, 2004; Overton, 1990). The results of the fashion and in consultation with adults. MacArthur Foundation Research Network’s earlier study We recognize that not all abortion decisions are de- of age differences in competence to stand trial, which liberative, rational, and autonomous and that not all crim- depends on individuals’ ability to understand facts about a inal decisions are impulsive, emotional, and influenced by court proceeding and to reason with those facts in a rational others. After all, any decision about whether to abort a fashion, also were consistent with these findings. We found pregnancy or carry it to term has an emotional component, significant differences between the competence-related involves both immediate and long-term consequences, and abilities of adults and those of adolescents who were 15 and may be influenced by the opinions of family and friends. younger, but no differences between the abilities of adults By the same token, adolescents’ crimes are occasionally and those of adolescents who were 16 and older (Grisso et strategic, planned in advance, and executed alone. In gen- al., 2003). This general pattern, indicating that adolescents eral, though, when contemplating an abortion, an adoles- attain adult levels of competence to stand trial somewhere cent has time to deliberate before making a final choice and around age 15, has been reported in similar studies of 586 October 2009 American Psychologist  psychosocial capacities that are relevant to debates about the relative maturity of adolescents and adults, especially as they affect judgments of criminal blameworthiness. There were five data collection sites in the study: Los Angeles; Irvine, CA; Denver; Philadelphia; and Washing- ton, DC. Data for the present study come from 935 indi- viduals ranging in age from 10 to 30 years (M ! 17.84 years). Participants were recruited via newspaper advertise- ments and flyers posted at community organizations, Boys & Girls Clubs, churches, community colleges, and local places of business in neighborhoods targeted to have an average household education level of “some college” ac- cording to 2000 U.S. Census data. Because we were inter- ested in characterizing the capacities of “average” adoles- cents and adults, we did not target individuals on the basis of their involvement with the legal system but sought instead to survey an ethnically and socioeconomically di- verse sample of individuals in the age range of interest. Individuals who were interested in the study were asked to call the research office listed on the flyer. Mem- Sandra bers of the research team described the nature of the study Graham to prospective participants over the telephone and invited those interested to participate. Given this recruitment strat- egy, it is not possible to know how many potential partic- ipants saw the advertisements, what proportion responded, decision making across a wide variety of domains (e.g., and whether those who responded were different from Grisso, 1980; Jacobs-Quadrel, Fischhoff, & Davis, 1993) those who did not, although the education level of the and in many studies of age differences in individuals’ sample is comparable to that of the people in the neigh- competence to provide informed consent (Belter & Grisso, borhoods from which it was drawn. 1984; Grisso & Vierling, 1978; Gustafson & McNamara, Data collection took place either at one of the partic- 1987; Weithorn & Campbell, 1982). ipating university’s offices or at a convenient location in In contrast, the literature on age differences in psy- the community. Before beginning, participants were pro- chosocial characteristics such as impulsivity, sensation vided verbal and written explanations of the study, their seeking, future orientation, and susceptibility to peer pres- confidentiality was assured, and their written consent or sure shows continued development well beyond middle assent was obtained. For participants who were under the adolescence and even into young adulthood (Scott, Rep- age of 18, informed consent was obtained from either a pucci, & Woolard, 1995; Steinberg & Cauffman, 1996), parent or a guardian. although few studies have gone much beyond adolescence Procedure (but see Cauffman & Steinberg, 2000, for an exception). Consistent with this literature, and in contrast to the pattern Prior to data collection, all site project directors and re- of age differences seen in the information-processing, log- search assistants met at one location for several days of ical reasoning, and informed consent literatures, studies of training. The project coordinators and research assistants age differences in the sorts of risky behavior likely to be conducted on-site practice protocol administrations prior to influenced by the psychosocial factors listed above—such enrolling participants. Participants took part in a two- to as reckless driving, binge drinking, crime, and spontaneous two-and-one-half-hour interview that included three sets of unprotected sex—indicate that risky behavior is signifi- measures: (a) a series of computerized tasks designed to cantly more common during late adolescence and early assess a range of executive functions (not discussed in this adulthood than after (Steinberg, 2007). In other words, report); (b) a series of questionnaires designed to measure although adolescents may demonstrate adult-like levels of a variety of psychosocial capacities relevant to discussions maturity in some respects by the time they reach 15 or 16, of how adolescents should be treated by the legal system; in other respects they show continued immaturity well and (c) tests of basic intellectual functioning. The tasks and beyond this point in development. questionnaires were administered on a laptop computer in individual interviews. Research assistants were present to The MacArthur Juvenile Capacity monitor the participant’s progress, reading aloud the in- Study structions as each new task was presented and providing assistance as needed. To keep participants engaged in the Participants computer tasks, we told the participants that they would The MacArthur Juvenile Capacity Study was designed to receive $35 for participating in the study and that they examine age differences in a variety of cognitive and could obtain up to a total of $50 (or, for participants who October 2009 American Psychologist 587  IQ. The Wechsler Abbreviated Scale of Intelligence (WASI) Full-Scale IQ Two-Subtest (FSIQ-2) (Psycholog- ical Corporation, 1999) was used to produce an estimate of general intellectual ability based on two (Vocabulary and Matrix Reasoning) of the four subtests. The WASI can be administered in approximately 15 minutes and is correlated with the Wechsler Intelligence Scale for Children (r !.81) and the Wechsler Adult Intelligence Scale (r !.87). It has been normed for individuals between the ages of 6 to 89 years. Because there were small but significant differences between the age groups in mean IQ, this variable was controlled for in all subsequent analyses. Psychosocial maturity. The battery of instru- ments contained self-report measures of five capacities frequently mentioned in discussions about age differences in maturity and their relevance to legal policy. Table 2 lists these measures and provides sample items from each. Three widely used and well-validated Likert-scale- type instruments were used to assess risk perception (the extent to which one perceives a potentially dangerous or harmful activity as risky), sensation seeking (the extent to Marie Banich which one actively seeks experiences that provide thrills), and impulsivity (the extent to which one acts without think- ing or has difficulty controlling impulses). Risk perception was assessed using a modified version of a widely used were under 14, an additional prize) depending on their measure developed by Benthin, Slovic, and Severson performance. In actuality, we paid all participants ages (1993). The respondent is presented with eight potentially 14 –30 the full $50, and all participants ages 10 –13 re- dangerous activities (e.g., riding in a car with a drunk ceived $35 plus a prize (approximately $15 in value). This driver, having unprotected sex) and asked to indicate how strategy was used to increase the motivation to perform risky the activity is (" !.82).1 Sensation seeking was well on the tasks but also to ensure that no participants assessed using a subset of six items (" !.70) from the were penalized for their performance. All procedures were Sensation Seeking Scale (Zuckerman, Eysenck, & Ey- approved by the institutional review board of the university senck, 1978).2 Impulsivity was assessed using all 18 items associated with the data collection site. (" !.73) from three six-item subscales of the Barratt Impulsiveness Scale (Patton, Stanford, & Barratt, 1995): Measures Motor Impulsivity, Inability to Delay Gratification, and Of interest in the present report are the demographic mea- Lack of Perseverance. All three self-report measures have sures and IQ (which were used to ensure that the various been shown to be significantly correlated with behavioral age groups had comparable social and intellectual back- indices of their associated constructs. In our sample, scores grounds), the measures of psychosocial capacities, and the on the impulsivity self-report measure were significantly tests of basic intellectual functioning. negatively related to the amount of time participants waited Demographic variables. Participants pro- before making their first move on a Tower of London task, vided information about their age, gender, ethnicity, and and scores on the sensation-seeking questionnaire were highest level of education within their household. For significantly correlated with sensation-seeking behavior in youths 17 years of age and younger, household education a video driving game (Steinberg et al., 2008). In addition, was based on parents’ level of education, as research has individuals who were less likely to perceive potentially indicated that parental education may be the most stable risky behaviors as risky were more likely to report engag- component of a family’s social class (Steinberg, Mounts, ing in high-risk behavior. Lamborn, & Dornbusch, 1991). For participants 18 years of age and older, their own educational attainment was used to 1 index this construct. In order to have cells with sufficiently The original Benthin et al. (1993) measure also contains an item concerning alcohol use. Our analyses indicated that including this item in large and comparably sized subsamples for purposes of the scale’s construction adversely differentiated the reliability of the scale data analysis, we created age groups as follows: 10 –11, among the younger and older participants, most likely because the use of 12–13, 14 –15, 16 –17, 18 –21, 22–25, and 26 –30 years. alcohol is risky for minors but not necessarily for adults. As a conse- The age groups did not differ with respect to gender or quence, we dropped that item from our scale computation. 2 ethnicity but did differ, albeit modestly, with respect to Many of the items on the full Zuckerman et al. (1978) scale appear to measure impulsivity, not sensation seeking (e.g., “I often do things on household education. Accordingly, all subsequent analyses impulse.”) Because we have a separate measure of impulsivity in our controlled for this variable. Demographic characteristics of battery, we used only the Zuckerman et al. items that clearly indexed thrill the sample are presented in Table 1. or novelty seeking (see Table 2). 588 October 2009 American Psychologist  ing statements that are both phrased in a socially acceptable Table 1 fashion, asked to indicate which best describes them, and Demographic Characteristics of the Sample (N ! 935) then asked whether the descriptor is “very true” or “sort of Characteristic Percentage true.” (This format is presumed to reduce social desirability bias.) Resistance to peer influence (Steinberg & Monahan, Age (in years) 2007) was assessed using a 10-item scale (" !.76) de- 10–11 12.5 signed to measure the extent to which individuals change 12–13 14.7 their behavior or opinions in order to follow the crowd. We 14–15 13.8 have no data on the validity of this measure in the current 16–17 15.2 sample, but we do in analyses of data from a large study of 18–21 15.9 serious juvenile offenders. There we found that the pres- 22–25 14.6 26–30 13.2 ence of antisocial peers in an individual’s network is more Gender highly correlated with the individual’s own criminal be- Male 49.2 havior among those who report a low ability to resist peer Female 50.8 influence on this measure than among those who have Ethnicity equally antisocial peers but score high in self-reported African American 29.2 resistance to peer influence (Monahan, Steinberg, & Cauff- Asian American 15.1 man, 2007). Studies of the neural underpinnings of resis- Hispanic 21.2 tance to peer influence using this measure have found White 24.0 neurobiological differences between same-age individuals Other/biracial 9.9 who vary in their resistance to peer influence in ways Household education High school 11.9 consistent with the notion that higher scores on this instru- High school graduate 22.8 ment reflect better coordination of affect and thinking Some college 34.1 (Grosbras et al., 2007; Paus et al., 2008), a key component College graduate 21.4 of psychosocial maturity in our conceptualization of the Postcollege 9.7 construct. Future orientation was assessed using a 15-item scale (" !.80) that measures the anticipation of future consequences, planning ahead, and thinking about the fu- ture. The validity of this measure is supported by our finding that individuals who score high on this scale are Two additional psychosocial capacities, resistance to more likely to choose a larger delayed reward over an peer influence and future orientation, were assessed using immediate smaller one in a delay discounting task (Stein- new self-report measures developed for this program of berg et al., 2009). work. Each used a response format introduced by Harter A composite measure of psychosocial maturity was (1982) in which respondents are presented with two oppos- formed by reverse-scoring the measures of impulsivity and Table 2 Indices of Psychosocial Maturity Construct Measure Sample item Risk perception Benthin et al., 1993 “If you did this activity (e.g., had unprotected sex), how much are you at risk for something bad happening?” Sensation seeking Zuckerman et al., 1978 “I sometimes like to do things that are a little frightening.” Impulsivity Patton et al., 1995 “I do things without thinking.” Resistance to peer influence Steinberg & Monahan, 2007 “Some people think it’s better to be an individual even if people will be angry at you for going against the crowd. BUT Other people think it’s better to go along with the crowd than to make people angry at you.” Future orientation Steinberg et al., 2009 “Some people take life one day at a time without worrying about the future. BUT Other people are always thinking about what tomorrow will bring.” October 2009 American Psychologist 589 sensation seeking so that higher scores indicated greater adolescents and cited sources that referred to both infor- maturity (i.e., more impulse control and less thrill seeking), mation-processing abilities (Keating, 1980) and logical rea- standardizing all five measures, and averaging the stan- soning (Inhelder & Piaget, 1958) in support of its argument dardized scores. Thus, individuals who score relatively that adolescents are as cognitively competent as adults. We lower on the composite characterize themselves as less acknowledge that our index, which tilts heavily toward likely to perceive dangerous situations as risky, more im- measuring how many pieces of information an individual pulsive, more thrill seeking, more oriented to the immedi- can process or produce, does not measure logical or moral ate, and more susceptible to peer influence. This is very reasoning and as such is an incomplete measure of cogni- similar to the portrait of adolescents described by Justice tive capacity as conceptualized in the APA Hodgson brief. Kennedy in his majority opinion in the juvenile death Our measure assesses cognitive ability in a highly struc- penalty case. A confirmatory factor analysis indicated that tured manner and as such does not tap aspects of executive the composite model fit the data well (comparative fit function that may be important in novel situations. It is also index !.95, root mean square error of approximation ! important to note that our measure of general cognitive.075). The five indicators are modestly, but significantly, capacity does not include tests of higher order executive intercorrelated (rs range from.14 to.38; average r !.26). functioning, such as comparing short- versus long-term Cognitive capacity. The test battery included consequences, coordinating affect and cognition, or balanc- several widely used tests of basic cognitive skills, including ing risk and reward. Many such executive functions have a test of resistance to interference in working memory both cognitive and psychosocial aspects to them, however, (Thompson-Schill et al., 2002), a digit-span memory test, and given that our interest was in maintaining a distinction and a test of verbal fluency. The resistance to interference between general cognitive and psychosocial capacities so in working memory test was one in which participants saw as to better examine their distinct developmental timeta- four probe letters on the screen and then a target. They bles, it was important not to conflate the two. The measures were then asked whether the target was among the four of psychosocial maturity and cognitive capacity are very probes. On test trials, two of the four letters presented had modestly correlated once age is controlled, r(922) !.15, appeared in the previous trial, providing interference with p #.001. Although our operationalization of general cog- recall on the present trial. An overall accuracy score was nitive capacity is not identical to that used by APA in its computed by averaging the number of correct responses argument, it is very clear that the authors of the Hodgson across all test trials. The digit-span memory test was sim- brief (APA, 1987) were referring to cognitive abilities and ilar to that in the Wechsler scales. Participants heard a not psychosocial maturity and that the authors of the Roper series of 13 sequences of digits (beginning with two digits brief (APA, 2004) were referring to psychosocial maturity and increasing to eight) that they were asked to recall and not cognitive capacity. forwards and 13 sequences that they were asked to recall Results backwards. A memory score was computed by averaging the total number of forward trials and backward trials Two analyses of covariance were conducted in order to recalled correctly. Finally, the measure of verbal fluency examine age patterns in psychosocial maturity and general asked participants to generate, in one minute, as many cognitive capacity; as noted earlier, both analyses con- words as possible that either began with a specific letter trolled for IQ and household education. (three trials) or were members of a category (e.g., fruits; The results of the two analyses are shown in Figures three trials). A verbal fluency score was computed by 1 and 2. Each figure presents the age group means for the averaging the number of words generated for each of the standardized composites, with a value of 1.0 added to each six lists. Because the composite consisted of only three items, it was not possible to derive a reliable estimate of internal consistency. However, after examining the intercorrela- tions among the tests, we found them to be significant Figure 1 (fluency and working memory, r !.29; working memory Psychosocial Maturity (Standardized Composite and digit span, r !.39; digit span and verbal fluency, r ! Scores) as a Function of Age (in Years).40). Accordingly, scores on each of the measures were standardized, and the standard scores were averaged to create an index of general cognitive capacity. Not surpris- ingly, our composite measure of general cognitive capacity is significantly correlated with IQ (r !.46, p #.001). Unlike IQ scores, however, which are adjusted for chrono- logical age, the measure of cognitive capacity is not. More important, because we controlled for IQ in all analyses, any observed age differences in general cognitive capacity are not due to age differences in intelligence. In its original amicus brief in Hodgson, the APA (1987) made reference to the “cognitive capacity” (p. 6) of 590 October 2009 American Psychologist Figure 2 Figure 3 General Cognitive Capacity (Standardized Composite Proportion of Individuals in Each Age Group Scoring at Scores) as a Function of Age (in Years) or Above the Mean for 26- to 30-Year-Olds on Indices of Cognitive Capacity and Psychosocial Maturity group’s mean for ease of presentation (i.e., to make all influence abortion decision making. As we noted earlier, in values positive numbers). The analysis of age differences addition to the present study, the MacArthur Network also in psychosocial maturity indicates a significant age effect, conducted a study of age differences in capacities related to F(6, 900) ! 12.577, p #.001. As Figure 1 indicates, age competence to stand trial (Grisso et al., 2003). The main differences in psychosocial maturity, as assessed in this instrument used to assess these capacities was the study, did not emerge until mid-adolescence but were present MacArthur Competence Assessment Tool—Criminal Ad- throughout late adolescence and early adulthood. Indeed, pair- judication (MacCAT–CA), a standardized interview that wise comparisons, using a Bonferroni correction, revealed no measures respondents’ understanding of and reasoning significant differences in psychosocial maturity among the about their legal situation (Poythress et al., 1999). Al- first four age groups (10 –11, 12–13, 14 –15, and 16 –17 years) though the abilities necessary for competence to stand trial but significant differences between the 16 –17-year-olds and are not identical to those necessary for competent decision those 22 and older, and between the 18 –21-year-olds and making about abortion, they are conceptually similar in that those 26 and older. In neither case was there a significant both involve being able to understand and reason with facts interaction between age and gender, indicating that the pat- and appreciate the nature of one’s situation. terns were the same among males and females. Figure 4 presents data from the present study along- The analysis of age differences in cognitive capacity side data from the Grisso et al. (2003) study in a way shows a very different pattern. As with psychosocial ma- turity, there is a highly significant age effect, F(6, 901) ! 58.246, p #.001. However, as Figure 2 indicates, age differences in cognitive capacity were evident during the Figure 4 first part of adolescence but not after age 16 —just the Proportion of Individuals in Each Age Group Scoring opposite from the pattern seen with respect to psychosocial at or Above the Mean for 22- to 24-Year-Olds on maturity. Pairwise comparisons using a Bonferroni correc- Index of Cognitive Capacity and on a Measure of tion indicated significant differences in general cognitive Abilities Relevant to Competence to Stand Trial capacity between each of the first four age groups but no age differences after age 16. Figure 3 presents these data in a somewhat different way. Here we show the proportion of individuals in each age group who scored at or above the mean level of the 26- to 30-year- olds in our sample on the psychosocial and cognitive com- posites, graphed in the same figure. As the figure indicates, general cognitive capacity reaches adult levels long before the process of psychosocial maturation is complete. Although our measure of cognitive capacity included several of the information-processing skills noted in the APA (1987) Hodgson brief but did not include indices of the sort of reasoning to which APA referred, it is important Note. MacCAT–CA ! MacArthur Competence Assessment Tool—Criminal to ask whether the pattern of age differences we found on Adjudication, Understanding and Reasoning subscales. MacCAT–CA data are this measure resembles that observed using measures of from Grisso et al (2003). more sophisticated cognitive abilities of the sort believed to October 2009 American Psychologist 591 comparable to that used in Figure 3, that is, in terms of the autonomy and/or culpability), which science alone cannot proportion of individuals of different ages who performed dictate. Nevertheless, the legal treatment of adolescents at or above the mean level of the adults in the sample. The should at the very least be informed by the most accurate Grisso et al. study included participants ages 11 to 24, and timely scientific evidence on the nature and course of drawn equally from the community and the justice system. psychological development. On the basis of the present In order to make the appropriate comparison of these data study, as well as previous research, it seems reasonable to to those of the present study, we excluded the justice distinguish between two very different decision-making system subsample from the analyses (the average IQ of that contexts in this regard: those that allow for unhurried, subsample was 85, substantially lower than that of the logical reflection and those that do not. This distinction is present study), categorized individuals into chronological also in keeping with our emerging understanding of ado- age groups that paralleled those used in the present study lescent brain maturation, which suggests that brain systems (11, 12–13, 14 –15, 16 –17, 18 –21, and 22–24 years), and responsible for logical reasoning and basic information used the oldest group as the adult reference category. processing mature earlier than those that undergird more Similarly, we reanalyzed the cognitive capacity data from advanced executive functions and the coordination of affect the present study after dropping the 10-year-olds, exclud- and cognition necessary for psychosocial maturity (Stein- ing individuals who were older than 24, and using 22- to berg, 2008). 24-year-olds as the adult reference category. When it comes to decisions that permit more deliber- As Figure 4 illustrates, the pattern of age differences ative, reasoned decision making, where emotional and so- in abilities relevant to competence to stand trial is virtually cial influences on judgment are minimized or can be mit- identical to the pattern seen with respect to general cogni- igated, and where there are consultants who can provide tive capacity as assessed in the present study. On both objective information about the costs and benefits of alter- indices, scores increased between ages 11 and 16 and then native courses of action, adolescents are likely to be just as leveled off, with no improvement after this age. This gives capable of mature decision making as adults, at least by the us greater confidence that the absence of age differences in time they are 16. Three domains of decision making that cognitive capacity after age 16 observed in our study is not would seem to fit into this category are medical decision merely a function of the fact that our index included only making (where health care practitioners can provide infor- measures of basic information-processing abilities. Rather, mation and encourage adolescents to think through their our reanalysis of the Grisso et al. (2003) data supports the decisions before acting), legal decision making (where argument that adolescents reach adult levels of cognitive legal practitioners, such as defense attorneys, can play a maturity several years before they reach adult levels of comparable role), and decisions about participating in re- psychosocial maturity. search studies (where research investigators, guided by institutional review boards, can function similarly). Al- Discussion though adults in these positions cannot and should not Developmental psychologists with expertise in adolescence make the decision for the adolescent, they surely can take are frequently called on to provide guidance about the steps to create a context in which adolescents’ decision- appropriate treatment of young people under the law and making competence will be maximized. The position taken about the proper placement of legal age boundaries be- by APA in Hodgson v. Minnesota (1990), in favor of tween those who should be treated as adults and those who granting adolescents’ access to abortion without the neces- should not. The results of the present study suggest that it sity of parental involvement, therefore seems to us to be is not prudent to make sweeping statements about the consistent with the available scientific evidence, so long as relative maturity of adolescents and adults, because the youngsters under the age of 16 have the opportunity to answer to the question of whether adolescents are as mature consult with other, informed adults (e.g., health care prac- as adults depends on the aspects of maturity under consid- titioners, counselors). eration. By age 16, adolescents’ general cognitive abilities In contrast, in situations that elicit impulsivity, that are are essentially indistinguishable from those of adults, but typically characterized by high levels of emotional arousal adolescents’ psychosocial functioning, even at the age of or social coercion, or that do not encourage or permit 18, is significantly less mature than that of individuals in consultation with an expert who is more knowledgeable or their mid-20s. In this regard, it is neither inconsistent nor experienced, adolescents’ decision making, at least until disingenuous for scientists to argue that studies of psycho- they have turned 18, is likely to be less mature than adults’. logical development indicate that the boundary between This set of circumstances likely characterizes the commis- adolescence and adulthood should be drawn at a particular sion of most crimes perpetrated by adolescents (which are chronological age for one policy purpose and at a different usually committed in groups and are seldom premeditated; one for another. Farrington, 2003; Zimring, 1998) and may also be typical Whether and how these findings should inform deci- of other situations where adolescents are emotionally sions about adolescents’ treatment under the law depends aroused, in groups, absent adult supervision, and facing on the specific legal issue under consideration. To varying choices with apparent immediate rewards and few obvious degrees, such decisions rely on value judgments (e.g., or immediate costs—the very conditions that are likely to about what aspects of maturity are relevant to a particular undermine adolescents’ decision-making competence decision or about what is mature “enough” to warrant (Steinberg, 2007). These conditions often prevail in situa- 592 October 2009 American Psychologist tions involving the purchase of alcohol and tobacco, driv- Hodgson v. Minnesota, 497 U.S. 417 (1990)]. Retrieved February 11, ing, and other potentially health-compromising behaviors, 2009, from http://www.apa.org/psyclaw/hodgson.pdf American Psychological Association. (1989, September 1). [Amicus cu- such as having unprotected sex. In these cases, adolescents’ riae brief filed in U.S. Supreme Court in Ohio v. Akron Center for relative immaturity should be acknowledged either by im- Reproductive Health, Inc., 497 U.S. 502 (1990) and Hodgson v. Min- posing greater restraints on their behavior than are imposed nesota, 497 U.S. 417 (1990)]. Retrieved February 11, 2009, from on adults (e.g., prohibiting the purchase of alcohol, restrict- http://www.apa.org/psyclaw/reproductivehealth.pdf American Psychological Association. (2004, July 19). [Amicus curiae ing driving to certain hours of the day or certain conditions) brief filed in U.S. Supreme Court in Roper v. Simmons, 543 U.S. 551 or by providing added protections (e.g., prohibiting capital (2005)]. Retrieved February 11, 2009, from http://www.apa.org/ punishment, making condoms easily accessible). Thus, psyclaw/roper-v-simmons.pdf APA’s argument that adolescents should not be subject to Ayotte v. Planned Parenthood of Northern New England, 546 U.S. 320 capital punishment owing to their impulsivity and suscep- (2006). Belter, R., & Grisso, T. (1984). Children’s recognition of rights violations tibility to peer pressure is consistent with the results of our in counseling. 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Be- havioral Sciences and the Law, 18, 741–760. with the differing nature of the decision-making scenarios Farrington, D. (2003). Developmental and life-course criminology: Key involved in each case. The skills and abilities necessary to theoretical and empirical issues. Criminology, 41, 221–225. make an informed decision about a medical procedure are Gilfoyle, N. (2005). Understanding APA’s amicus curiae brief in Roper v. likely in place several years before the capacities necessary Simmons. Retrieved February 11, 2009, from http://www.apa.org/ releases/ropervsimmons.html to regulate one’s behavior under conditions of emotional Grisso, T. (1980). Juveniles’ capacities to waive Miranda rights: An arousal or coercive pressure from peers. empirical analysis. California Law Review, 68, 1134 –1166. Science alone cannot dictate public policy, although it Grisso, T., & Steinberg, L. (2005). Between a rock and a soft place: can, and should, inform it. 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