UNCORRECTED PROOF 1 2 Preschoolers’ aggression and parent–child conflict: 3 A multiinformant and multimethod study 4 Jamie M. Ostrov * , Christa M. Bishop 5 Department of Psychology, State University of New York, University at Buffalo, Buffalo, NY 14260, USA 6 Received 10 August 2007; revised 3 January 2008 7 8 Abstract 9 This multiinformant and multimethod study (N = 47) investigated the link between the parent– 10 child relationship system and the display of physical and relational aggression with peers at school 11 during early childhood. Children (mean age = 43.54 months, SD = 8.02) were observed (80 min/ 12 child) during free play, and parents and teachers were asked to complete several standard measures. 13 Intercorrelations between aggression subtypes revealed moderate to high levels of correlation for 14 parents and teachers and no significant association for observations of physical and relational 15 aggression. Interinformant agreement was examined, and teachers and parents were found to 16 significantly agree for both physical and relational aggression, and teachers and observers also 17 significantly agreed for both subtypes of aggression. Results of regression analyses suggest that 18 parent–child conflict was uniquely associated with relational aggression among peers when 19 controlling for physical aggression and gender. Ways in which these findings build on the extant 20 literature are discussed. 21 Ó 2008 Elsevier Inc. All rights reserved. 22 Keywords: Relational aggression; Physical aggression; Parent–child relationship; Early childhood; Observation; 23 Peer 24 25 Introduction 26 Recently, researchers have begun to focus their attention on the use of relational 27 aggression during early childhood (e.g., Crick, Casas, & Mosher, 1997; Hawley, 2003; Nel- 0022-0965/$ - see front matter Ó 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.jecp.2008.01.001 * Corresponding author. Fax: +1 716 645 3801. E-mail address: jostrov@buffalo.edu (J.M. Ostrov). Available online at www.sciencedirect.com Journal of Experimental Child Psychology xxx (2008) xxx–xxx www.elsevier.com/locate/jecp YJECP 2989 No. of Pages 14, Model 1+ 8 February 2008 Disk Used ARTICLE IN PRESS Please cite this article in press as: Ostrov, J. M., & Bishop, C. M., Preschoolers’ aggression and par- ent–child conflict: ..., Journal of Experimental Child Psychology (2008), doi:10.1016/j.jecp.2008.01.001