Cruel and Unusual Punishment: The Juvenile Death PenaltyAdolescence, Brain Developmentand Legal CulpabilityJanuary 2004“[They] frequently know the difference between right andwrong and are competent to stand trial. Because of their impair-ments, however, by definition they have diminished capacities tounderstand and process mistakes and learn from experience, toengage in logical reasoning, to control impulses, and to understandthe reactions of others…. Their deficiencies do not warrant anexemption from criminal sanctions, but they do diminish their per-sonal culpability.” Atkins v. Virginia, 536 U.S. 304, 318, 122 S.Ct. 2242, 2250 (2002)In 2002, the U.S. Supreme Court banned the execution ofmentally retarded persons. This decision, Atkins v. Virginia,cited the underdeveloped mental capacities of those withmental retardation as a major factor behind the Justices’decision. Adolescence is a transitional period during which a child isbecoming, but is not yet, an adult. An adolescent is at a cross-roads of changes where emotions, hormones, judgment, identi-ty and the physical body are so in flux that parents and evenexperts struggle to fully understand.As a society, we recognize the limitations of adolescents and,therefore, restrict their privileges to vote, serve on a jury, con-sume alcohol, marry, enter into contracts, and even watchmovies with mature content. Each year, the United States spendsbillions of dollars to promote drug use prevention and sex edu-cation to protect youth at this vulnerable stage of life. When itcomes to the death penalty, however, we treat them as fully func-tioning adults. The Basics of the Human BrainThe human brain has been called the most complex three-pound mass in the known universe. This is a well deserved rep-utation, for this organ contains billions of connections amongits parts and governs countless actions, involuntary and volun-tary, physical, mental and emotional. The largest part of the brain is the frontal lobe. A small areaof the frontal lobe located behind the forehead, called the pre-frontal cortex, controls the brain’s most advanced functions. Thispart, often referred to as the “CEO” of the body, provideshumans with advanced cognition. It allows us to prioritizethoughts, imagine, think in the abstract, anticipate conse-quences, plan, and control impulses. Along with everything else in the body, the brain changessignificantly during adolescence. In the last five years, scientists,using new technologies, have discovered that adolescent brainsare far less developed than previously believed.New Technology, New DiscoveriesScientists are now utilizing advances in magnetic resonanceimaging (MRI) to create and study three-dimensional images ofthe brain without the use of radiation (as in an x-ray). Thisbreakthrough allows scientists to safely scan children over manyyears, tracking the development of their brains.1Researchers at Harvard Medical School, the NationalInstitute of Mental Health, UCLA, and others, are collaboratingto “map” the development of the brain from childhood to adult-hood and examine its implications.American Bar Association l Juvenile Justice Center740 15th Street, NW Washington, DC 20005 • 202.662.1506 • [email protected] • www.abanet.org/crimjust/juvjusA three dimensional “map” showing portions of gray matter “pruned”from the brain between adolescence and adulthood. The dark portionsin the two boxes indicate sections that will be discarded from thefrontal lobe. The box on the far right indicates the prefrontal cortex,a subsection of the frontal lobe that controls judgment. Image adapted from Nature Neuroscience.2 ■ American Bar Association ■ January 2004of the brain, rather than the frontal lobe. She explains, “one ofthe things that teenagers seem to do is to respond more strong-ly with gut response than they do with evaluating the conse-quences of what they’re doing.”7Also, appearances may be deceiving: “Just because they’rephysically mature, they may not appreciate the consequences orweigh information the same way as adults do. So we may be mis-taken if we think that [although] somebody looks physicallymature, their brain may in fact not be mature.”8This discovery gives us a new understanding into juveniledelinquency. The frontal lobe is “involved in behavioral facetsgermane to many aspects of criminal culpability,”9explains Dr.Ruben C. Gur, neuropsychologist and Director of the BrainBehavior Laboratory at the University of Pennsylvania. “Perhapsmost relevant is the involvement of these brain regions in thecontrol of aggression and other impulses…. If the neural sub-strates of these behaviors have not reached maturity beforeadulthood, it is unreasonable to expect the behaviors themselvesto reflect mature thought processes.“The evidence now is strong that the brain does not ceaseto mature until the early 20s in those relevant parts that governimpulsivity, judgment, planning for the future, foresight of con-sequences, and other characteristics that make people morallyculpable…. Indeed, age 21 or 22 would be closer to the ‘biolog-ical’ age of maturity.”10Other Changes in the BodyIn addition to the profound physical changes of the brain,adolescents also undergo dramatic hormonal and emotionalchanges. One of the hormones which has the most dramaticeffect on the body is testosterone. Testosterone, which is closelyassociated with aggression, increases tenfold in adolescentboys.11Emotionally, an adolescent “is really both part child and partadult,”12explains Melvin Lewis, an expert in child psychiatryand pediatrics at Yale University School of Medicine. Normaldevelopment at this time includes self-searching, during whichthe adolescent tries to grow out of his or her childlike self. Thischange is complicated by the conflict between an adolescent’snew sense of adult identity and remaining juvenile insecurities.The scientists, to their surprise, discovered that the teenagebrain undergoes an intense overproduction of gray matter (thebrain tissue that does the “thinking”). Then a period of “prun-ing” takes over, during which the brain discards gray matter at arapid rate.2This process is similar to pruning a tree: cutting backbranches stimulates health and growth.In the brain, pruning is accompanied by myelination, aprocess in which white matter develops. White matter is fatty tis-sue that serves as insulation for the brain’s circuitry,