Brain Science and the Theory of Juvenile Mens Rea

62 Pages Posted: 8 May 2015 Last revised: 6 Jun 2016

See all articles by Jenny E. Carroll

Jenny E. Carroll

University of Alabama - School of Law

Date Written: May 7, 2015


The law has long recognized the distinction between adults and children. A legally designated age determines who can vote, exercise reproductive rights, voluntarily discontinue their education, buy alcohol or tobacco, marry, drive a car, or obtain a tattoo. The Supreme Court has repeatedly upheld such age-based restrictions, most recently constructing an Eighth Amendment jurisprudence that bars the application of certain penalties to juvenile offenders and a Fourth Amendment jurisprudence that contemplates an adolescent-based standard of reasonableness for the Miranda v. Arizona custody analysis. In the cases of Roper v. Simmons , Graham v. Florida , Miller v. Alabama , and J.D.B. v. North Carolina , the Court’s jurisprudence of youth relies on emerging neuroscience to confirm what the parents of any teenager have long suspected: adolescents’ cognitive abilities and thought processes differ from their adult counterparts. Children are different than adults.

In the cases of Roper, Graham, and Miller, the Court recognized that brain development affects the legal construct of culpability and should accordingly affect punishment. In the Roper case line, the Court reasoned that without mature thought processes and cognitive abilities, adolescents as a class fail to achieve the requisite level of culpability demonstrated in adult offenders. As such, juveniles were categorically spared the death penalty and, in some instances, a sentence of life in prison without the possibility of parole. Likewise, in J.D.B., the Court concluded that the reasonableness of a juvenile defendant’s perception of custody under Miranda v. Arizona must be age-appropriate. The Court concluded that as a class adolescents had a different understanding of custodial status than adults. Courts contemplating the validity of a perception of custody under Miranda had to account for this difference in their analysis.

To date, the Court has limited the application of this principle to punishment and consent analysis under Miranda. The logic of the Court’s decisions, however, applies just as strongly to the application of substantive criminal law. Likewise, scholars writing in the field have limited the application of neuroscience to either the territory staked out by the Court or to objective mens rea standards alone. The science, however, does not support such limitations. Just as modern neuroscience counsels against the imposition of certain penalties on juvenile offenders and an adjustment of Miranda’s reasonableness analysis, so it counsels toward a reconsideration of culpability as applied to juvenile offenders through the element of mens rea. The failure to extend this jurisprudence of youth to every mental state element undermines the very role of mens rea as a mechanism to determine guilt.

Keywords: Mens rea, juvenile, brain development, criminal law, culpability

Suggested Citation

Carroll, Jenny Elizabeth, Brain Science and the Theory of Juvenile Mens Rea (May 7, 2015). 94 North Carolina Law Review 539 (2016), Available at SSRN:

Jenny Elizabeth Carroll (Contact Author)

University of Alabama - School of Law ( email )

P.O. Box 870382
Tuscaloosa, AL 35487
United States

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