Patterns of Reactive and Proactive Aggression in Young Adolescents in Singapore Joyce S. Pang, Rebecca P. Ang, Dennis M.Y. Kom, Ser Hong Tan and Aaron Q. M. Chiang, Nanyang Technological University Abstract The authors investigated the patterns of reactive and proactive aggression exhibited by young male (N = 604) and female (N = 544) adolescents in Singapore. Self-report measures of reactive and proactive aggression, behavioral and emotional adjust- ment, parenting styles, and delinquency were administered to students aged 13–14. Using cluster analysis, three distinct patterns of aggression emerged: a low aggres- sive group, a combined aggressive group with high reactive and proactive aggres- sion, and a reactively aggressive group with low proactive and high reactive aggression. The two aggressive groups showed similar disturbances in adjustment and delinquency, but the combined group showed the greatest disruptions. Findings indicate cross-cultural stability of patterns of aggression as well as the usefulness of the reactive/proactive distinction in early identification of individuals with adjust- ment problems. Keywords: reactive and proactive aggression; behavioral and emotional adjustment; delinquency; cluster analysis Introduction Childhood aggression is a good early predictor of later conduct problems (e.g., Fite, Raine, Stouthamer-Loeber, Loeber, & Pardini, 2010). However, not all types of aggres- sion in childhood lead to conduct problems later, and those that do have different developmental trajectories (e.g., Tolan, Guerra, & Kendall, 1995). Varying courses indicate that the phenomenon of childhood aggression is heterogeneous. Greater knowledge about subtypes of aggression, their risk factors, and developmental trajec- tories could lead to a clearer theoretical understanding of aggression. Numerous classification systems exist for aggression, typically organized around either the form or the function of the aggressive act. For instance, aggressive acts can be distinguished by its forms: physical/verbal, active/passive, direct/indirect, Correspondence should be addressed to Joyce S. Pang, Division of Psychology, School of Humani- ties and Social Sciences, Nanyang Technological University, Singapore 637332. Email: joycepang@ ntu.edu.sg Social Development Vol 22 No. 4 794–812 November 2013 doi: 10.1111/sode.12024 © 2013 John Wiley & Sons Ltd