Expanding the Age of Adolescence: Implications for Criminal Justice Reform

Expanding the Age of Adolescence: Implications for Criminal Justice Reform

When does a child become an adult?

Answering this question has always been inherently arbitrary. Yet, how we define adolescence—the period of life between childhood and adulthood—has important implications for how society’s institutions treat adolescents.

In a new article published in The Lancet, a group of scientists argue for expanding the period of adolescence from 10-19 to 10-24 years of age. The authors suggest that this re-conceptualization more accurately reflects lifestyle patterns that have changed in recent decades, and is supported by advances in scientific research. A more inclusive definition of adolescence has implications for many areas of policy, including, importantly, criminal justice.

Traditionally, the onset of puberty has marked the beginning of adolescence. The endpoint, however, has been less clearly defined, differing based on cultural and social norms. The passage from adolescence to adulthood has been typically marked by transitions out of education and into employment, marriage, and parenting—life events which occur at later ages now than in previous decades.

Arguments for extending the upper age range of adolescence have also been informed by recent insights in psychology and neuroscience, which show that the development of the brain—and the mental functions it supports—continues well into a person’s 30s. In particular, neuroimaging studies have shown that key brain areas involved in executive control, decision-making, and regulating emotions are not mature in adolescents. Similarly, because these regulatory circuits are not yet fully developed, adolescents are more susceptible to influence by peers and more inclined to impulsive, risk-taking behaviors.

For these reasons, many scientists and policy makers have been calling for a re-definition of adolescence. These arguments have been often framed through the lens of juvenile justice because re-conceptualizing adolescence can drastically alter how the juvenile justice system treats adolescents. Indeed, this debate has led to recent reforms in the juvenile justice system.

Most notably, in April 2017, New York State passed “Raise the Age” legislation, increasing the age of criminal responsibility to 18 years. Prior to this, New York and North Carolina were the only two states in the U.S. to automatically prosecute all 16- and 17-year-olds as adults, regardless of the offense. Such changes counter-act much of the draconian “tough-on-crime” legislation supported by both Republicans and Democrats over the last several decades, and moves toward a system more focused on prevention and rehabilitation than retribution. Scientific research was essential to moving this campaign forward.

On the other side of the debate, some argue that expanding adolescence to 24 years and raising the age of criminal responsibility infantilizes youth and allows them to skirt responsibility for their actions. However, adjusting the severity of punishment does not mean that a crime will go unpunished—it is merely adjusting the consequence to fit the crime.

Besides issues of culpability, there are two other important reasons why scientific research on adolescence is critical to consider for criminal justice reform. Both reasons hinge upon the fact that adolescence is a sensitive period of brain development, meaning that the brain is malleable and can be shaped by both positive and negative life experiences.

On one hand, this malleability means that adolescence may be a ‘window of vulnerability,’ during which time traumatic experiences may impair adolescent development. In line with this, evidence from a longitudinal study shows long-term negative effects on psychosocial maturity following incarceration during adolescence. Evidently, the stress of being incarcerated may leave a lasting impact on youth and actually promote antisocial and aggressive behaviors, thus likely putting others at danger once one is released.

On the other hand, adolescence may also be a ‘window of opportunity.’ The heightened plasticity of the adolescent brain means that it may also be particularly responsive to positive, prosocial influences. Thus, policies and programs that promote rehabilitative rather than punitive treatment may be more effective in facilitating positive outcomes. Increasingly, there is support for the idea that science can inform when and how justice programs and interventions can be implemented to maximize positive outcomes for adolescents.

Research on adolescence will continue to be important for informing evidence-based practices and moving forward progressive criminal justice reforms. Among these, expanding the age of adolescence may be a viable pathway not only to improving adolescent health, development, and well-being, but also to creating a fairer and more just criminal justice system.


Stephen Braren is a PhD student at NYU Steinhardt who studies cognitive and brain development in contexts of socioeconomic inequality.