Cognitive and affective development in adolescence Laurence Steinberg Department of Psychology, Temple University, Philadelphia, PA 19122, USA Questions about the nature of normative and atypical development in adolescence have taken on special significance in the last few years, as scientists have begun to recast old portraits of adolescent behavior in the light of new knowledge about brain development. Adolescence is often a period of especially heightened vulnerability as a consequence of potential disjunctions between developing brain, behavioral and cognitive systems that mature along different timetables and under the control of both common and independent biological processes. Taken together, these develop- ments reinforce the emerging understanding of adoles- cence as a critical or sensitive period for a reorganization of regulatory systems, a reorganization that is fraught with both risks and opportunities. Introduction Adolescence is characterized by an increased need to regulate affect and behavior in accordance with long-term goals and consequences, often at a distance from the adults who provided regulatory structure and guidance during childhood. Because developing brain, behavioral and cognitive systems mature at different rates and under the control of both common and independent biological processes, this period is often one of increased vulner- ability and adjustment. Accordingly, normative develop- ment in adolescence can profitably be understood with respect to the coordination of emotional, intellectual and behavioral proclivities and capabilities, and psychopathol- ogy in adolescence may be reflective of difficulties in this coordination process. The notion that adolescence is a heightened period of vulnerability specifically because of gaps between emotion, cognition and behavior has important impli- cations for our understanding of many aspects of both normative and atypical development during this period of the life-span. With respect to normative development, for instance, this framework is helpful in understanding age differences in judgment and decision-making, in risk- taking, and in sensation-seeking [1]. With respect to atypical development, the framework helps us to under- stand why adolescence can be a time of increased risk for the onset of a wide range of emotional and behavioral problems, including depression, violent delinquency and substance abuse [2]. Questions about the nature of normative and atypical development in adolescence have taken on special signifi- cance in the last few years as scientists have begun to recast old portraits of adolescent psychological develop- ment in light of new knowledge about adolescent brain development. Recent discoveries in the area of develop- mental neuroscience have stimulated widespread scien- tific and popular interest in the study of brain development during adolescence, as well as substantial speculation about the connections between brain matu- ration and adolescents’ behavioral and emotional devel- opment. Indeed, the topic has garnered such widespread public interest that it was the subject of a recent cover story in Time magazine aimed at parents of teenagers [3], and was raised in arguments submitted in late 2004 to the United States Supreme Court in connection with the Court’s consideration of the constitutionality of the juvenile death penalty [4]. Brain development in adolescence As reviewed in the accompanying article by Paus [5] there is growing evidence that maturational brain processes are continuing well through adolescence. Even relatively simple structural measures, such as the ratio of white- to-gray matter in the brain, demonstrate large-scale changes into the late teen-age years [6–8]. The impact of this continued maturation on emotional, intellectual and behavioral development has yet to be thoroughly studied, but there is considerable evidence that the second decade of life is a period of great activity with respect to changes in brain structure and function, especially in regions and systems associated with response inhibition, the cali- bration of risk and reward, and emotion regulation. Contrary to earlier beliefs about brain maturation in adolescence, this activity is not limited to the early adolescent period, nor is it invariably linked to processes of pubertal maturation (Figure 1). Two particular observations about brain development in adolescence are especially pertinent to our under- standing of psychological development during this period. First, much brain development during adolescence is in the particular brain regions and systems that are key to the regulation of behavior and emotion and to the perception and evaluation of risk and reward. Second, it appears that changes in arousal and motivation brought on by pubertal maturation precede the development of regulatory competence in a manner that creates a disjunction between the adolescent’s affective experience Corresponding author: Steinberg, L. (lds@temple.edu). Available online 23 December 2004 Review TRENDS in Cognitive Sciences Vol.9 No.2 February 2005 www.sciencedirect.com 1364-6613/$ - see front matter Q 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.tics.2004.12.005