Adolescent Brain Development - the Youth Advocacy Division

Adolescent Brain Development
Quick Reference Fact Sheet
Background
• With the recent cases of Graham v. Florida (2010), Roper v. Simmons (2005), Atkins v. Virginia (2002), and
Thompson v. Oklahoma (1988), the topics of adolescent brain development and juvenile culpability have come to
the forefront of juvenile criminal law. In Graham, the Supreme Court declared it unconstitutional to sentence
juveniles convicted of non-homicide offenses to life without the possibility of parole. In Thompson and Roper, the
Supreme Court declared it unconstitutional to give the death penalty to juveniles (Thompson set the age limit to
16, Roper to 18). In each of these cases, the underlying rationale was that juvenile offenders tend to lack maturity
(both socially and biologically), are more reckless, are more susceptible to peer pressure, and are more vulnerable
to their surroundings than adults. In both Graham and Atkins, the topic of brain development played a crucial role
in the Court determining that the sentence in question was not appropriate in light of the lessened culpability of
the category of offenders challenging the sentence (juveniles in Graham, mentally retarded individuals in Atkins).
Indeed, the Graham decision went as far as stating that “An offender’s age is relevant to the 8 th amendment, and
criminal procedure laws that fail to take defendants’ youthfulness into account at all would be flawed.” Graham v.
Florida, No. 08-7412, slip. op at 25, 560 U.S. __ (2010)
• Adolescent brain development has become an increasingly accurate field of research in recent years due to the
development of magnetic resonance imaging (MRI) procedures. Prior to the use of MRI technology, the only
major studies that had been performed involved post-mortem (cadaver) tissue, since X-rays and other means of
testing were deemed potentially harmful to youth. MRI technology allows for the same subject to be tracked from
infancy into adulthood. 1
• States and the federal government generally do not recognize youth as being mature enough to handle many
situations. For example, youth cannot drive until age 16 (varies by state, w/ most adopting restrictions on under 18
drivers), or see rated R movies without adult supervision until they are 17. They cannot vote, smoke, sign
contracts, enter military services, or get married (varies by state) until age 18. And lastly, they cannot drink until
age 21. The implications of these social norms indicates that society does not fully trust youth with many
privileges, and thus do not consider them as responsible as adults. 2
Implications
• As compared to adults, juveniles have a “‘lack of maturity and an underdeveloped sense of responsibility’”; they
“are more vulnerable or susceptible to negative influences and outside pressures, including peer pressure”; and
their characters are “not as well formed.” 3
• “The evidence is strong that the brain does not cease to mature until the early 20s in those relevant parts that
govern impulsivity, judgment, planning for the future, foresight of consequences, and other characteristics that
make people morally culpable.” 4
• “Neuroscientists have been able to demonstrate conclusively that mental maturation follows closely the time
course of brain maturation. Thus, juveniles have to rely on the abilities of their still immature brains, and no
amount of social intervention or self-motivation can appreciably influence the biological processes involved in
brain maturation.” 5
• “The cortical regions that are last to mature… are involved in behavioral facets germane to many aspects of
criminal culpability. Perhaps most relevant is the involvement of these brain regions in the control of aggression
and other impulses, the process of planning for long-range goals, organization of sequential behavior,
consideration of alternatives and consequences, the process of abstraction and mental flexibility, and aspects of
memory including ‘working memory.’… If the neural substrates of these behaviors have not reached maturity
before adulthood, it is unreasonable to expect the behaviors themselves to reflect mature thought processes.”
[Emphasis Added]. 6