NEUROBIOLOGICAL DEVELOPMENT IN ADOLESCENCE AND EARLY ADULTHOOD:

https://doi.org/10.1037/0000298-038 APA Handbook of Adolescent and Young Adult Development, L. J. Crockett, G. Carlo, and J. E. Schulenberg (Editors) Copyright © 2023 by the American Psychological Association. All rights reserved. Since the advent of magnetic resonance imaging (MRI) and the first MRI scans of children in the 1990s, the study of the developing brain has increased exponentially, contributing to our understanding of both typical and atypical brain development. Prior to MRI, much of our understanding of brain development came from studies of people who suffered brain damage to particular parts of the brain or from postmortem studies of youth who had died prematurely. The ability to study the developing brain in vivo has provided unprecedented opportunities to further our understanding of changes in the brain across the lifespan. Based on functional and structural MRI research over the past 2 decades, we now know that the brain is rapidly changing and adapting to its environment across the first 3 decades of life and beyond. Indeed, adolescence is marked by dramatic changes in brain development, second only to infancy, with continued neural development well into the 20s and 30s. Such developmental changes in the brain promote learning, skill acquisition, empathy, and prosocial behaviors, which contribute to positive youth development (Crone & Fuligni, 2020; Telzer, 2016). At the same time, the adolescent brain has been portrayed as defective and viewed as the cause of suboptimal behaviors. Media depictions of the adolescent brain are fraught with images of teens’ brains with regions dedicated to sex, sleep, and emotional liability. For example, an article in the Wall Street Journal titled “What’s Wrong With the Teenage Mind? ” included a graphic of a teen’s brain with regions for “angst,” “self-control under construction,” and “L8R” (Gopnik, 2012). Although well-intentioned and meant to be humorous, such media depictions of adolescent brain development paint an overwhelmingly negative picture of adolescence. Although portrayed less, many positive and adaptive behaviors are highlighted by the media as well, including adolescents engaging in youth-led demonstrations, such as demonstrations to promote antigun violence or address climate change. In fact, the activists of the youth movement March for Our Lives were short listed for person of the year by Time Magazine in 2018, and Greta Thunberg, an adolescent activist for climate change, was the 2019 person of the year. Nonetheless, examples of adolescents engaging in positive behaviors are often overlooked or attributed to a select few, which may reinforce the stereotype of negative behaviors of adolescence. Characterizing the adolescent brain as immature and broken may contribute to negative stereotypes of adolescents. Indeed, public perceptions of the teenage brain are largely negative. For example, when asked to generate free associations with the word “teenage brain,” adolescents and adults described undesirable behaviors (e.g., “irresponsible,” “lazy,” “irritating”) more often than desirable behaviors (e.g., “independent,” “kind,” “creative”; Altikulaç et al., 2019). Such stereotypes can affect Ch a p t e r 38