At approximately the same time that these policy changes were being adopted across the
country, a new body of science was emerging. For the first time, advances in imaging technology
made it possible to study the human brain as it develops from childhood through adolescence and
into adulthood.6 Among other things, these studies enabled neuroscientists to validate empirically
what the original juvenile court reformers had gleaned through observation and experience—that
behaviors typically associated with youthful offending, including impulsivity, risk-taking, undue
peer influence, and poor judgment—are closely linked to the immature status of the young brain.7
This apparent disconnect between the emergent science of adolescent development and the
evolving landscape of juvenile justice policy led the John D. and Catherine T. MacArthur
Foundation to establish the Research Network on Adolescent Development and Juvenile Justice.8
The goal of the Network was to examine juvenile justice policies and practices through the lens of
rigorous science and scholarship. Over the next several years, the Network published a series of
briefs, reports and research papers on issues such as the link between adolescent development and
youth culpability,9 adolescents’ competence to stand trial,10 and the impact of adult versus juvenile
sanctioning.11 In less than two decades, the work of these and other developmental scientists
changed the arc of the American juvenile justice system, transitioning it from one that viewed
modern-day youth as a new breed of dangerous criminal to one willing to give young offenders a
“culpability-discount” based on an enhanced understanding of the biological, psychological and
social distinctions between youth and adults. Most notably, the U.S. Supreme Court relied heavily
on the adolescent development literature in striking down the juvenile death penalty,12 and in
severely curtailing juvenile life without parole sentences for youth under age eighteen.13
In 2004, motivated by the new brain science studies and the work of its Research Network,
the MacArthur Foundation began what would eventually become a $165 million investment in
6 See Jay N. Giedd, et al., Brain Development During Childhood and Adolescence: a Longitudinal MRI Study, 2
NATURE NEUROSCIENCE 861 (1999) (reporting on the results of pediatric neuroimaging studies and finding differences
in the brain’s architecture between pre-adolescence and adolescence).
7 See REFORMING JUVENILE JUSTICE: A DEVELOPMENTAL APPROACH
91 (Richard J. Bonnie, Robert L. Johnson, Betty
M. Chemers & Julie A. Schuk eds., 2013) (noting that empirical evidence suggests that children and adults differ in
three essential ways: self-regulation in emotionally charged situations; heightened sensitivity to peer influence; and a
lesser ability to make decisions based on future ramifications). See also Jeffrey Arnett, Reckless Behavior in
Adolescence: A Developmental Perspective, 12 DEV. REV. 339 (1992).
8 See MACARTHUR FOUNDATION RESEARCH NETWORK ON ADOLESCENT DEVELOPMENT & JUVENILE JUSTICE, Our
http://www.adjj.org/content/about_us.php (last visited Feb. 2, 2016).
9 See, e.g., Laurence Steinberg & Elizabeth S. Scott, Less Guilty by Reason of Adolescence: Developmental
Immaturity, Diminished Responsibility, and the Juvenile Death Penalty, 58 AM. PSYCHOL. 1009 (2003). This article
was cited by the U.S. Supreme Court in its decision in Roper v. Simmons, invalidating the juvenile death penalty as a
violation of the Eighth Amendment’s cruel and unusual punishment prohibition. See Roper v. Simmons, 543 U.S. 551,
10 See, e.g., Thomas Grisso, et al., Juveniles’ Competence to Stand Trial: A Comparison of Adolescents’ and Adults’
Capacities as Trial Defendants, 27 L. AND HUM. BEHAV. 333 (2003).
11 Thomas A. Loughran, et al., Differential Effects of Adult Transfer on Juvenile Offender Recidivism, 34 LAW. AND
HUM. BEHAV. 476–88 (2010).
12 Roper v. Simmons, 543 U.S. 551, 569–70 (2005) (invalidating capital punishment for juveniles as cruel and unusual
punishment and identifying developmental differences between juveniles and adults as central to its decision to
prohibit the execution of persons under the age of eighteen).
13 Graham v. Florida, 560 U.S. 48 (2010) (banning the use of life without parole sentences for juveniles not convicted
of murder); Miller v. Alabama and Jackson v. Hobbs, 132 S. Ct. 2455 (2012) (invalidating mandatory life without
parole sentences and noting that adolescence is a time of “transient rashness, proclivity for risk, and an inability to
assess consequences”); Montgomery v. Louisiana, 136 S.Ct. 6 (2015) (holding that the decision in Miller v. Alabama
finding mandatory juvenile life without parole unconstitutional applies retroactively).