Brain Responses to Surprising Sounds Are Related to Temperament and Parent–Child Dyadic Synchrony in Young Children Anu-Katriina Pesonen 1,2 Minna Huotilainen 3,4 Kati Heinonen 1 Niina Komsi 1 Vesa Putkinen 3,4 Lauri Kivikoski 1 Mari Tervaniemi 3,4 1 Institute of Behavioral Sciences University of Helsinki PO Box 9, 00014 Helsinki, Finland E-mail: anukatriina.pesonen@helsinki.fi 2 Institute of Clinical Medicine University of Helsinki Helsinki, Finland 3 Cognitive Brain Research Unit Institute of Behavioral Sciences University of Helsinki Helsinki, Finland 4 Finnish Center of Excellence in Interdisciplinary Music Research Helsinki, Finland ABSTRACT: This study investigated the relationship between temperament characteristics, parent–child dyadic synchrony and auditory event-related potentials (ERP) in 15 two-year-old children. Temperament was assessed with the Early Childhood Behavior Questionnaire, and parent–child dyadic synchrony was analyzed from video-taped play situations. Involuntary switching of attention toward surprising sounds was measured with auditory ERPs by quantifying the P3a response for repeated and nonrepeated novel, naturally varying sounds, presented in a continuous repetitive sound sequence. Lower negative emotionality, higher effortful control and higher dyadic synchrony were associated with larger P3a responses to repeated novel sounds. The results demonstrate that temperament is related to P3a responses in early childhood, and that parent–child synchrony associates with both temperament and P3a responses in a theoretically meaningful way. ß 2010 Wiley Periodicals, Inc. Dev Psychobiol 52: 513–523, 2010. Keywords: attention; child; ERP; synchrony; temperament INTRODUCTION Temperament characteristics refer to biologically-based, individual differences in reactivity and self-regulation (Rothbart & Ahadi, 1994; Rothbart, Ahadi, & Evans, 2000). Early appearing differences in temperament characteristics have been shown to exert modest to moderate continuity from infancy to childhood (Aksan et al., 1999; Komsi et al., 2006, 2008; Lemery, Goldsmith, Klinnert, & Mrazek, 1999; Putnam, Rothbart, & Gart- stein, 2008). Importantly, the acquired level of self- regulation by the age of three is considered to be an important developmental hallmark (Kochanska, Murray, & Harlan, 2000), contributing to the development of emotion regulation and socialization (Rothbart & Ahadi, 1994). Effortful control refers to the ability to inhibit behavioral and emotional responses, regulate attention, and to find pleasure in activities with low intensity level. Research on older children and adults has revealed that effortful control is linked with several neural circuits contributing to attentional function, which, in turn, serves as the basic mechanism underlying our awareness of the world (Fan, McCandliss, Fossella, Flombaum, & Posner, 2005; Posner, 2005; Rueda et al., 2004; Rueda, Rothbart, McCandliss, Saccomanno, & Posner, 2005; Sheese, Rothbart, Posner, White, & Fraundorf, 2008). Already at birth, infants are different from each other in their attention-related characteristics (Fan et al., 2005; Rueda et al., 2004). These early characteristics, or temperament dispositions, are defined as orienting to sensory events (attentional persistence or duration of Developmental Psychobiology Received 30 June 2009; Accepted 22 February 2010 Correspondence to: A.-K. Pesonen Contract grant sponsor: FP6-2004-NEST-PATH-028570-Brain- Tuning, The Academy of Finland Contract grant numbers: 128115, 1128103 Published online 7 April 2010 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/dev.20454 ß 2010 Wiley Periodicals, Inc.