Report Prepared by Laurence Steinberg, Ph.D.
Name of Expert: Laurence Steinberg, DR.
Area of Expertise: Psychiatry & Psychology >> Psychology
Representing: Plaintiff
Jurisdiction: W.D.Tex.
PROFESSIONAL POSITION
1. My name is Laurence Steinberg. My address is 1924 Pine Street, Philadelphia, Pennsylvania, 19103, USA.
2. I hold the degrees of A.B. in Psychology from Vassar College (Poughkeepsie, New York) and Ph.D. in Human Development and Family Studies from Cornell University (Ithaca, New York).
3. I am a developmental psychologist specializing in adolescence, broadly defined as the period of life between 10 and 25. I am on the faculty at Temple University, in Philadelphia, Pennsylvania, USA, where I am the Distinguished University Professor and Laura H. Carnell Professor of Psychology. I am a member and Fellow of the American Psychological Association and the Association for Psychological Science, a member of the Society for Research in Child Development and the Society for Research on Adolescence, and a Fellow of the American Academy of Arts and Sciences. I was a member of the National Academies' Board on Children, Youth, and Families and chaired the Academies' Committee on the Science of Adolescence. I was President of the Division of Developmental Psychology of the American Psychological Association and President of the Society for Research on Adolescence.
4. I received my Ph.D. in 1977 and have been continuously engaged in research on adolescent development since that time. I am the author or co-author of approximately 400 scientific articles and 17 books on young people. Prior to my appointment at Temple University, where I have been since 1988, I was on the faculty at the University of Wisconsin-Madison (1983-1988) and the University of California, Irvine (1977-1983). From 1997-2007, I directed the John D. and Catherine T. MacArthur Foundation Research Network on Adolescent Development and Juvenile Justice, a national multidisciplinary initiative on the implications of research on adolescent development for policy and practice concerning the treatment of juveniles in the legal system. I am currently a member of the MacArthur Foundation Research Network on Law and Neuroscience, a national initiative examining the ways in which neuroscientific research may inform and improve legal policy and practice.
5. Although my work has focused broadly on adolescent psychological development, I have a special interest in the development of judgment and decision-making, which I have been studying for nearly 20 years. In my capacity as chair of the National Academies' Committee on the Science of Adolescence, I organized and oversaw several workshops on adolescent risk-taking and its consequences for health and well-being. The summary of these workshops, which was published in 2011, discusses findings from recent research on adolescent brain development and the implications of this work for understanding why adolescents often display poor judgment in a range of situations.
6. Since 1997, I have been engaged in research on the implications of research on adolescent development for legal decisions about the behavior of young people. More specifically, my colleagues and I have been studying whether, to what extent, and in what respects adolescents and adults differ in ways that may inform decisions about the treatment of juveniles under the law.
7. The work that my colleagues and I have conducted has had demonstrable impact on American jurisprudence. Most significantly, it was cited and/or quoted verbatim in the majority opinion of the United States Supreme Court in Roper v. Simmons, the 2005 case that abolished the juvenile death penalty, and in both Graham v. Florida (2010), which banned the imposition of the sentence of life without parole for juveniles convicted of crimes other than homicide, and Miller v. Alabama / Jackson v. Hobbs (2012) (subsequently referred to in this report as “Miller”), which banned mandatory sentences of life without parole for juveniles, even those convicted of homicide. In these cases, I served as the lead scientist in the drafting of amicus briefs filed by the American Psychological Association, which argued that adolescents' neurobiological and behavioral immaturity warranted treating them differently than adults.
8. It is my professional opinion that the diminished decision-making capacity and heightened inclination toward risky behavior among adolescents and young adults, relative to older individuals, is a critical consideration in the present matter.
9. This report is prepared at the request of Mr. Robert Wilson, an attorney in the Law Offices of Thomas J. Henry. I have been asked to discuss what is known about psychological and neurobiological development of individuals during adolescence and young adulthood and to render an opinion as to what this research suggests regarding the judgment and decision-making of individuals in their early 20s.
DOCUMENTS
10. I have received and read the following documents: the Plaintiff's Second Amended Complaint, Deposition of Driver Zackary Brooks, the Deposition of Mary Janus, the Deposition of Edward Freeman, the Deposition of Greg Sierra, and the Deposition of Leticia Dawson. All documents were provided by Mr. Wilson's office.
RELEVANT U.S. SUPREME COURT OPINIONS
11. In its majority opinion in Roper, the U.S. Supreme Court noted that “As any parent knows, and as the scientific and sociological studies...tend to confirm, a lack of maturity and an underdeveloped sense of responsibility are found in youth more often than in adults. These qualities often result in impetuous and ill-considered actions and opinions.”
12. In Graham, the Court reiterated the logic behind its ruling in Roper and noted that “No recent data provide reason to reconsider the Court's observations in Roper about the nature of juveniles.... ... Developments in psychology and brain science continue to show fundamental differences between juvenile and adult minds. For example, parts of the brain involved in behavior control continue to mature through late adolescence.”
13. In Miller, the Court reiterated the logic behind its prior rulings, in Roper and Graham, and noted that “the science and social science supporting Roper's and Graham's conclusions have become even stronger”; that “[A]n ever-growing body of research in developmental psychology and neuroscience continues to confirm and strengthen the Court's conclusions”; and that, “It is increasingly clear that adolescent brains are not yet fully mature in regions and systems related to higher-order executive functions such as impulse control, planning ahead, and risk avoidance.”
14. Although these Supreme Court cases concern the juvenile death penalty and the use of life without the possibility of parole in juvenile sentencing, I believe that the general points made by the Court in its majority opinions extend to situations in which young people must exercise mature judgment.
SCIENTIFIC KNOWLEDGE ABOUT PSYCHOLOGICAL AND NEUROBIOLOGICAL DEVELOPMENT IN ADOLESCENCE AND YOUNG ADULTHOOD
15. Several conclusions that have emerged from scientific research on brain and psychological development in adolescence are especially relevant to the present case (for a recent summary, see Steinberg, L. (2014). Age of Opportunity: Lessons from the New Science of Adolescence. New York: Houghton Mifflin Harcourt). As noted above, in this report, “adolescence” refers to the period of development extending from 10 to 25. Where a distinction among age groups within this range is important, I use the phrase “late adolescents” to refer to individuals who are between 18 and 25. (In some scientific writings, these individuals have been referred to as “emerging adults.”)
16. First, adolescents are more likely than adults to underestimate the number, seriousness, and likelihood of risks involved in a given situation. When asked to make a decision about a course of action, compared to adults, adolescents have more difficulty identifying the possible costs and benefits of each alternative, underestimate the chances of various negative consequences occurring, and underestimate the degree to which they could be harmed if the negative consequences occurred (see Grisso, T., Steinberg, L., Woolard, J., Cauffman, E., Scott, E., Graham, S., Lexcen, F., Reppucci, N., & Schwartz, R. (2003). Juveniles' competence to stand trial: A comparison of adolescents' and adults' capacities as trial defendants. Law and Human Behavior, 27, 333-363).
17. Second, adolescents are more likely than adults to engage in what psychologists call “sensation-seeking,” that is, the pursuit of arousing, rewarding, or novel experiences. As a consequence of this, adolescents are more apt to focus on the potential rewards of a given decision while neglecting to consider the potential costs (see Steinberg, L., Albert, D., Cauffman, E., Banich, M., Graham, S., & Woolard, J. (2008). Age differences in sensation seeking and impulsivity as indexed by behavior and self-report: Evidence for a dual systems model. Developmental Psychology, 44, 1764-1778). Other studies have indicated that heightened sensation-seeking among adolescents is due to the greater attention they pay to the potential rewards of a risky choice relative to the potential costs (Cauffman, E., Shulman, E., Steinberg, L., Claus, E., Banich, M., Graham, S., & Woolard, J. (2010). Age differences in affective decision making as indexed by performance on the Iowa Gambling Task. Developmental Psychology, 46, 193-207). This tendency is especially pronounced among individuals between the ages of 18 and 21.
18. Third, adolescents are less able than adults to control their impulses and consider the future consequences of their actions and decisions. In general, adolescents are more short-sighted and less planful, and they have more difficulty than adults in foreseeing the possible outcomes of their actions and regulating their behavior accordingly (see Steinberg, L., Graham, S., O'Brien, L., Woolard, J., Cauffman, E., & Banich, M. (2009). Age differences in future orientation and delay discounting. Child Development, 80, 28-44). Importantly, gains in impulse control continue to occur during the mid-20s (see Steinberg, L., Albert, D., Cauffman, E., Banich, M., Graham, S., & Woolard, J. (2008) Age differences in sensation seeking and impulsivity as indexed by behavior and self-report: Evidence for a dual systems model. Developmental Psychology, 44, 1764-1778).
19. Fourth, the development of basic cognitive abilities, including memory and logical reasoning, matures before the development of emotional maturity, including the ability to exercise self-control, properly consider the risks and rewards of alternative courses of action, and resist coercive pressure from others. Basic cognitive abilities reach adult levels of maturity
by age 16, but emotional maturation is ongoing into the early 20s, a phenomenon that has been referred to as a “maturity gap.” As a consequence of this gap between intellectual and emotional maturity, the tendencies of adolescents, relative to individuals in their mid-20s, to be more focused on rewards, more impulsive, and more myopic are exacerbated when adolescents are making decisions in situations that are emotionally arousing, such as those that generate negative emotions, such as fear, threat, or anxiety. Accordingly, adolescents' deficiencies in judgment, relative to adults, are greater under circumstances in which emotions are aroused (Steinberg, L., Cauffman, E., Woolard, J., Graham, S., & Banich, M. (2009). Are adolescents less mature than adults? Minors' access to abortion, the juvenile death penalty, and the alleged APA “flip-flop”. American Psychologist, 64, 583-594).
20. In a recent study my colleagues and I conducted we assessed individuals' impulse control while experimentally manipulating their emotional state. Under conditions during which individuals were not emotionally aroused, individuals between 18 and 21 were able to control their impulses as well as those in their mid-20s, but under emotionally arousing conditions, 18- to 21-year olds demonstrated impulsive behavior comparable to those in their mid-teens (Cohen, A. et al. (2015). When does an adolescent become an adult? Assessing cognitive capacity under emotional influences. Paper under review.)
21. Like emotional arousal, fatigue also increases the risk for poor judgment among adolescents. The combination of immature self-control and fatigue has been linked to driving accidents among adolescent drivers (Dahl, R. (2008). Biological, developmental, and neurobehavioral factors relevant to adolescent driving risks. American Journal of Preventive Medicine, 35, S278-S284). According to a report from the Institute of Medicine, the peak age for “falling-asleep accidents” is in the late teens and early 20s. Contrary to popular belief, the peak time of day for adolescent crashes due to sleepiness is during the morning, not at night (Institute of Medicine. (2007). Preventing Teen Motor Crashes: Contributions from the Behavioral and Social Sciences: Workshop Report. Washington (DC): National Academies Press). Just one night's sleep deprivation can significantly impair adolescents' behavioral functioning. Inadequate nighttime sleep during adolescence has been linked to daytime sleepiness, cognitive difficulties, slower reaction times, and inattentiveness (Beebe, D. W. (2011). cognitive, behavioral, and functional consequences of inadequate sleep in children and adolescents. Pediatric Clinics of North America, 58, 649-665; Louca, M., & Short, M. (2014). The effect of one night's sleep deprivation on adolescent neurobehavioral performance. SLEEP, 37, 1799-1807).
22. The combination of heightened attentiveness to rewards and still-maturing impulse control makes middle and late adolescence a period of greater risk taking than any other stage of development. This has been demonstrated both in studies of risk-taking in psychological experiments (when other factors, such as outside influences, can be controlled) and in the analysis of data on risky behavior in the real world. In recent experimental studies of risk taking in the lab, the peak age for risky decision-making was between 19 and 21 (Braams, B., van Duijvenvoorde, A., Peper, J., & Crone, E. (2015). Longitudinal changes in adolescent risk-taking: A comprehensive study of neural responses to rewards, pubertal development and risk taking behavior. Journal of Neuroscience, 35, 7226-7238; Shulman, E., & Cauffman, E. (2014). Deciding in the dark: Age differences in intuitive risk judgment. Developmental Psychology, 50, 167-177).
23. This age trend is consistent with epidemiological data on age trends in risky behavior, which show peaks in the adverse outcomes of risk-taking in the late teens and early 20s on a wide range of behaviors, including driver deaths, unintended pregnancy, arrests for violent and non-violent crime, and binge drinking (for a review, see Willoughby, T., Good, M., Adachi, P.J.C., Hamza, C.A., & Tavernier, R. (2013). Examining the link between adolescent brain development and risk taking from a social-developmental perspective. Brain and Cognition, 83, 315-323).
24. The tendency of adolescents to show heightened sensation-seeking and poor impulse control is demonstrably greater among males than females (Shulman, E., Harden, K., Chein, J., & Steinberg, L. (2015). Sex differences in the developmental trajectories of impulse control and sensation-seeking from early adolescence to early adulthood. Journal of Youth and Adolescence, 44, 1-17), as is the tendency toward risky decision-making (Shulman, E., & Cauffman, E. (2014). Deciding in the dark: Age differences in intuitive risk judgment. Developmental Psychology, 50, 167-177). Thus, to the extent that this combination increases the chance that individuals will engage in reckless behavior, the risk for this will be greatest among young men in their late teens and early 20s.
25. Recent research on brain development sheds light on the biological underpinnings of these age differences in judgment and decision-making and supports the conclusion that adolescents are inherently less able than adults to regulate their impulses; give proper consideration to the longer-term consequences of their decisions; appropriately attend to the risks, as well as the rewards, of their options; and resist the coercive influence of others. There is broad consensus among scientists on these points. There is considerable scientific evidence that these characteristics of adolescent decision-making are attributable to neurobiological immaturity.
26. Scientists also agree that brain maturation continues well beyond the teen years. Specifically, research on neurobiological development shows continued maturation into the early- or even mid-20s of brain regions and systems that govern various aspects of self-regulation and executive function (i.e., higher-order cognitive skills, such as planning and thinking ahead). These developments involve structural (anatomical) and functional (activity) changes in the prefrontal and parietal cortices (Gogtay, N., et al. (2004). Dynamic mapping of human cortical development during childhood through early adulthood. Proceedings of the National Academies of Sciences, 101, 8174-8179. Hedman A., van Haren N., Schnack H., Kahn R., & Hulshoff Pol, H. (2012). Human brain changes across the life span: A review of 56 longtitudinal magnetic resonance imaging studies. Human Brain Mapping, 33, 1987-2002; Pfefferbaum, A., Rohlfing, T., Rosenbloom, M., Chu, W., & Colrain, I. (2013). Variation in longitudinal trajectories of regional brain volumes of healthy men and women (ages 10 to 85 years) measured with atlas-based parcellation of MRI. Neurolmage, 65, 176-193; Simmonds, D., Hallquist, M., Asato, M., & Luna, B. (2014). Developmental stages and sex differences of white matter and behavioral development through adolescence: A longitudinal diffusion tensor imaging (DTI) study. Neurolmage, 92, 356-368) as well as improved structural and functional connectivity between cortical and subcortical regions (Dosenbach, N., et al. (2011). Prediction of individual brain maturity using fMRI. Science, 329, 1358-1361; Fair, D., et al. (2009). Functional brain networks develop from a “local to distributed” organization. PLoS Computational Biology, 5, 1-14; Sowell, E., et al. (2004). Longitudinal mapping of cortical thickness and brain growth in normal children. Journal of Neuroscience, 24, 8223-8231.)
27. Many scientists, including myself, believe that the main underlying cause of immaturity in judgment during middle and late adolescence is the different timetables along which two important brain systems change during adolescence, sometimes referred to as a “maturational imbalance.” The system that is responsible for the increase in sensation-seeking and reward-seeking that takes place in adolescence undergoes dramatic changes very early in adolescence, around the time of puberty. Attentiveness to rewards remains high through the late teen years and into the early 20s. But the system that is responsible for self-control, regulating impulses, thinking ahead, evaluating the rewards and costs of a risky act, and resisting peer pressure is still undergoing significant maturation well into the mid-20s (Casey, B. J., et al. (2010). The storm and stress of adolescence: Insights from human imaging and mouse genetics. Developmental Psychobiology, 52, 225-235; Steinberg, L. (2008). A social neuroscience perspective on adolescent risk-taking. Developmental Review, 28, 78-106; Van Leijenhorst, L., Moor, B. G., Op de Macks, Z. A., Rombouts, S. A. R. B., Westenberg, P. M., & Crone, E. A. (2010). Adolescent risky decisionmaking: Neurocognitive development of reward and control regions. Neurolmage, 51, 345-355). Thus, during middle and late adolescence there is an imbalance between the reward system and the self-control system that inclines adolescents toward sensation-seeking and impulsivity.
28. As this “maturational imbalance” diminishes, during the mid-20s, there are improvements in such capacities as impulse control, resistance to peer pressure, planning, and thinking ahead (for reviews, see Albert, D., & Steinberg, L. (2011). Judgment and decision making in adolescence. Journal of Research on Adolescence, 21, 211-224; and Blakemore, S-J., & T. Robbins, T. (2012). Decision-making in the adolescent brain. Nature Neuroscience, 15, 1184-1191).
29. It is believed that, because of their relative immaturity in brain systems that govern self-control, adolescents are more vulnerable to the effects of fatigue and emotional arousal than are adults (Albert, D., & Steinberg, L. (2011). Judgment and decision making in adolescence. Journal of Research on Adolescence, 21, 211-224; Louca, M., & Short, M. (2014). The effect of one night's sleep deprivation on adolescent neurobehavioral performance. SLEEP, 37, 1799-1807).
APPLICATION OF SCIENTIFIC FINDINGS TO THE PRESENT MATTER
30. There is strong scientific evidence that individuals in their late teens and early 20s are characterized by immaturity in judgment that leave them prone, especially in emotionally arousing situations and when fatigued, to make decisions that are impulsive, myopic, and ill-considered. Inadequate sleep is likely to have a more debilitating effect on adolescents than on older individuals, leading to slower response times and inattentiveness, as well as daytime sleepiness.
31. Immaturity of judgment at this age has been linked to incomplete brain maturation, especially in brain systems responsible for impulse control and self-regulation. This suggests that there is a strong biological basis for the deficient judgment and risky behavior often displayed by individuals in their late teens and early 20s, especially when they are tired or emotionally aroused.
32. Given these neurobiological differences, it is sensible for organizations to have different policies that regulate the behavior of individuals in their late teens and early 20s versus those who are older. To date, most discussion of this issue has concerned the treatment of individuals who have violated the law, but a similar line of reasoning can be reasonably extend to decisions about the behavior of young people in other contexts, including work settings. This is especially important for organizations that oversee young people who are in positions in which poor judgment or risky decision making can have harmful consequences.
33. Individuals whose self-regulatory abilities are still immature require additional measures to prevent risky and reckless behavior. I have argued elsewhere that education alone is unlikely to be an effective means of preventing adolescent risk taking (Steinberg, L. (2014). Age of opportunity: Lessons from the new science of adolescence. New York: Houghton Mifflin Harcourt). Instead, I recommend policies and practices that limit opportunities for young people to put themselves in situations in which their natural inclinations toward risky behavior can result in harm to themselves and others. Such policies and practices might involve providing additional or more vigilant supervision by older individuals and/or placing restrictions on the activities and situations in which adolescents are permitted to engage on their own.
STATEMENT OF TRUTH
34. Throughout my report I have attempted to be accurate and complete and to discuss all matters that I regard as being relevant to the opinions expressed within my report.
35. I have indicated the source of any factual information upon which I have based an opinion on facts.
36. I have not included anything in my report that has been suggested to me by anyone without forming my own view on the matter.
37. I have received payment for my consultation with counsel and for the preparation of this report. 38. Where a range of reasonable opinion is present, I have indicated the extent of that range in my report.
39. If I believe that my existing report requires any correction or qualification, I will notify my instructing attorneys immediately in writing. If the correction or qualification is significant, I will prepare a supplementary report as soon as possible.
40. I believe that the facts I have stated in this report are true and that the opinions I have expressed are correct.