Abstract
For attachment and emotion regulation, behavioral and affective attunement between caregiver and child are essential (Stern, 1985). Especially sensitive caregiving is associated with behavioral and physiological synchrony during mother-child interactions (Leclère, 2014). Interpersonal synchronization of brain activity, posited to be an underlying mechanism to behavioral synchrony, is only recently being addressed in developmental research (Reindl et al. 2018, Piazza et al., 2018). Neural synchrony is proposed to facilitate communication and temporal contingency (Hasson et al., 2012). Here, we present a dual functional near-infrared spectroscopy (dual-fNIRS) study looking at the relationship between quality of mother-child interaction during a problem-solving task and neural synchrony.
In the present investigation, preschoolers and their mothers were tested simultaneously with dual-fNIRS (Figure 1). In the cooperation condition, mother and child were instructed to solve a tangram puzzle together where a template has to be recreated by arranging simple geometric shapes. In the individual condition, mother and child performed the same task alone with an opaque screen in between them. In a third condition, mother and child were engaged in a free verbal conversation. Finally, a resting phase (closed eyes) served as a baseline.
The following self-reports and behavioral data were collected in order to test our hypothesis that maternal attachment, caregiving, and sensitivity affect mother-child neural synchrony: Experiences in Close Relationships, and Parental Sensitivity Questionnaire. In addition, we assessed quality of the mother-child interaction during the collaborative task with a customized coding scheme, including scales from the Parent-Child Interaction System (PARCHISY), the Coding System for Mother-Child Interactions (CSMCI), and INTAKT.
Our sample consisted of 42 mother-child dyads (19 boys and 23 girls). Children’s mean age was 5;08 years (SD= 0;03 years; range=5;00-6;01 years). The mothers’ age averaged at 36.6 years (SD=4.29 years; range=28-46 years). 48% of mothers graduated from vocational school, the remaining mothers graduated with a university degree.
Wavelet transform coherence (WTC) was used to assess the cross-correlation between the two fNIRS time series. For statistical analyses, WTC values were entered as the dependent variable in a linear mixed effects model with condition (cooperation vs. individual vs. talk vs. rest) and channel (16 per dyad) as fixed factors, and a random intercept. Results (Figure 2) revealed a main effect of condition due to increased coherence in frontal and temporal areas during the collaboration condition and free verbal conversation, t(2566)=3.77-4.47, p<.001 and t(2566)=5.02-5.71, p<.0001. Testing the hypothesis that neural synchrony facilitated task performance, coherence during collaboration indeed predicted the number of templates solved, t=1.95, p=.05. However, task performance was also predicted by coherence during rest, t=2.80, p=.005. Looking at the quality of mother-child interaction, mutual task engagement predicted coherence during the collaboration condition, F(1,35)=5.60, p=.02. Further analyses relating inter-brain coherence to differences in the quality of the parent-child interaction are underway.
Data from the above study will be complemented with a follow-up investigation testing father-child neural synchrony with further measures of attachment. Results will be discussed in the context of variables affecting the quality of parent-child interactions and the potential functional role of interpersonal neural synchronization.
