Child Evidence

Adolescent personality and character are still forming and are not rel · Child Evidence

adolescent personality development / desistance

Adolescent personality and character are still forming and are not reliable indicators of fixed adult character; most adolescents who engage in antisocial behavior, including serious offending, desist as they mature, so adolescent conduct is a poor predictor of irretrievable depravity.

For the Court

There is broad agreement that most adolescents, even serious offenders, desist as they mature, and that adolescent character is not yet settled. The unresolved problem is prediction — science cannot reliably tell in advance which individual belongs to the small persistent subgroup.

What This Claim Does NOT Say

Does not claim every adolescent offender will desist, or that any individual is guaranteed to change.
Does not claim adolescents bear no responsibility because their character is unformed.
Does not claim science can predict, for a particular adolescent, whether they will reoffend or reform.
Does not deny that a small subgroup shows persistent antisocial behavior across the life course.
Does not claim malleability means treatment always succeeds, or that risk is zero.

Scope — Where It Holds

A developmental generalization grounded in longitudinal desistance research. It holds most strongly for the typical (adolescence-limited) pattern of offending, which is far more common than the persistent pattern; a small subgroup shows continuity into adulthood. Predictions are probabilistic at the group level and cannot identify which individual will desist or persist.

Sources & Verification

Seminal

Monahan, K. C., Steinberg, L., Cauffman, E., & Mulvey, E. P (2009). Trajectories of antisocial behavior and psychosocial maturity from adolescence to young adulthood. Developmental Psychology, 45(6), 1654-1668.
Longitudinal · adolescence to young adulthood
Youth whose antisocial behavior persists into adulthood show lower and arrested development of psychosocial maturity, indicating that persistent offending reflects maturational deficits rather than fixed character.
Bearing on this claim: Longitudinal: persistent offending tracks arrested psychosocial maturation, not fixed character.
doi.org/10.1037/a0015862

Supporting

Mulvey, E. P., Steinberg, L., Piquero, A. R., Besana, M., Fagan, J., Schubert, C., & Cauffman, E (2010). Trajectories of desistance and continuity in antisocial behavior following court adjudication among serious adolescent offenders. Development and Psychopathology, 22(2), 453-475.

Precedent Bridge

Relied on by

Roper v. Simmons (2005): "the character of a juvenile is not as well formed as that of an adult. The personality traits of juveniles are more transitory, less fixed."543 U.S. 551 (2005)

Graham v. Florida (2010): a life-without-parole sentence "cannot be justified by the goal of rehabilitation" and is "not appropriate in light of a juvenile nonhomicide offender's capacity for change and limited moral culpability."560 U.S. 48 (2010)

Miller v. Alabama (2012): given "children's diminished culpability and heightened capacity for change... appropriate occasions for sentencing juveniles to this harshest possible penalty will be uncommon."567 U.S. 460 (2012)

Limits & Counter-considerations

Desistance research cannot prospectively identify which individual will persist; samples are often male and U.S.-based; self-report offending measures have known biases; and definitions of "desistance" vary across studies, affecting reported proportions.

Full Dossier

Last reviewed June 18, 2026