Activation of the mirror system

Activation of the mirror system during action observation already has been demonstrated in infancy (Marshall and Meltzoff, 2011). Investigating the relation between neural mirroring and interpersonal coordination is especially important in early childhood, since proficiency in social interaction at this age, mainly with peers, predicts social competence later in life (e.g., Hay et al., 2009; Rubin et al., 2006). Children already demonstrate action coordination with peers in toddlerhood (e.g., Ashley and Tomasello, 1998; Brownell, 2011; Endedijk et al., 2015a; Hunnius et al., 2009). During the preschool years, children’s interpersonal coordination continues to develop, as they begin to respond more quickly to the behavior of others and become more stable in coordination, both in cooperation (Ashley and Tomasello, 1998; Endedijk et al., 2015a; Fletcher et al., 2012) and in entrainment tasks (Endedijk et al., 2015b). Throughout early childhood, children gain ample experience with interpersonal coordination. Children who face difficulties with social interactions early in life more often experience rejection by peers later on (Friedlmeier, 2009; NICHD Early Child Care Research Network, 2008) with subsequent negative consequences for their social functioning in adolescence and adulthood (Bagwell et al., 1998). Clarifying the processes involved in early interpersonal coordination with peers is very important for understanding social development. The current study examined the relation between interindividual differences in neural mirroring and young children’s social interaction skills. Children’s neural mirroring was assessed by measuring oscillatory endothelin receptor antagonist activity (by means of EEG) during action observation. In particular, the mu- and beta-frequency bands over motor areas have been associated with motor system involvement during action observation (cf. Meyer et al., 2011; Pfurtscheller and Lopes da Silva, 1999; Pineda, 2008; Saby and Marshall, 2012; Vanderwert et al., 2013). To investigate the relation between neural mirroring and interpersonal coordination with peers, motor system involvement during action observation was assessed in 4-year-old children. As part of a longitudinal study their interpersonal coordination had been assessed earlier at 28, 36, and 44 months, in a cooperation task and in an entrainment task with different peers. Based on previous research suggesting the functional involvement of neural mirroring during interpersonal coordination (Meyer et al., 2011; Naeem et al., 2012), we hypothesized that interindividual differences in children’s neural mirroring of others’ actions would be associated with both forms of interpersonal coordination (cooperation and entrainment).
Method
Results
Discussion The relation between motor system involvement during action observation and children’s peer coordination is consistent with previous findings that mirroring is related to more reliable imitation (Bernier et al., 2007; Filippi et al., 2016; Warreyn et al., 2013), better interpersonal coordination of finger movements (Naeem et al., 2012), and fewer turn-taking errors (Meyer et al., 2011). However, these previous studies measured neural mirroring and behavioral performance during the same instance of social interaction (i.e. one laboratory task) and thus did not address whether this relation is task-specific or reflects interindividual differences that generalize to social interactions outside the specific task. To capture various forms of peer interaction, we investigated two types of interpersonal coordination: goal-directed cooperation, and entrainment without an overt common goal. We found that neural mirroring was related to children’s performance in the cooperation task but not in the entrainment task. This is consistent with previous research that highlighted the importance of goals for action mirroring (Koski et al., 2002). Bekkering et al. (2009) argued that monitoring and predicting another person’s goal rather than their movements is important for interpersonal coordination because Incompatibility often requires co-actors to perform different movements to achieve a common goal. In the current cooperation task also, children had to assume complementary roles that required monitoring of each other’s actions.