How-to: 5 Steps for Brain-Building Serve and Return

There is large amount of evidence from developmental psychology about the importance of contingent, reciprocal interaction (“serve and return”) for many aspects of early childhood development (see Working Paper 1). But how do we know it actually “builds brains”? An increasing number of more recent studies, utilizing brain imaging and other new technologies, now document the impact of nurturing, supportive interaction and “sensitive caregiving” on both brain function and structure. A sampling of these studies are cited below.

1. “Neuroimaging revealed a neural mechanism by which language experience may influence brain development; namely, children who experienced more conversational turns exhibited greater activation in left inferior frontal regions (Broca’s area) during language processing, which explained nearly half the relationship between children’s language exposure and verbal abilities.”

Romeo, R.R., Leonard, J.A., Robinson, S.T. et al. (2018). Beyond the 30-million-word gap: Children’s conversational exposure is associated with language-related brain function. Psychological Science, 29(5), 700-710.

2. “Sensitive parental care, characterized by prompt and adequate response to the child’s signals and needs, predicts a more secure attachment relationship, higher levels of cognitive competence, and fewer psychological problems.”“Parental sensitivity in early childhood was positively associated with markers of more optimal brain development at age 8 years, including a larger total brain volume, larger gray matter volume, and thicker cortices in the precentral, postcentral, caudal middle frontal, and rostral middle frontal gyrus.”

Kok, R., Thijssen, S., Bakermans-Kranenburg, M. et al. (2015). Normal variation in early parental sensitivity predicts child structural brain development. Journal of the American Academy of Child and Adolescent Psychiatry, 54(10), 824–831.

3. “Variations in typical mother–infant interactions are associated with differences in infant brain volumes. Specifically, we found that lower maternal sensitivity was correlated with smaller subcortical grey matter volumes”

Sethna, V., Pote, I., Wang, S. et al. (2017). Mother–infant interactions and regional brain volumes in infancy: An MRI study, Brain Structure and Function, 222, 2379–2388.

4. “After considering age at imaging, household income and postnatal maternal anxiety, regression analyses demonstrated significant indirect associations between maternal sensitivity and bilateral hippocampal volume at six months. … Moreover, functional analyses revealed direct associations between maternal sensitivity and connectivity between the hippocampus and areas important for emotional regulation and socio-emotional functioning.”

Rifkin-Graboi, A., Kong, L., Sim, L.W. et al. (2015). Maternal sensitivity, infant limbic structure volume and functional connectivity: A preliminary study. Translational Psychiatry, 5, e668.

5. “Parent–child synchrony provides the first experience of nonverbal resonance where the mother adapts her gaze, affective expression, vocal quality, and movements to the infant’s earliest signals to create a shared dialog. Synchrony supports the development of abilities that sustain social engagement, including symbol formation, moral understanding, emotion regulation, and frustration tolerance and provides a template for biological synchrony; during synchronous moments parent and child coordinate their heart rhythms⁴⁸, neural response²⁸, and oxytocin release⁴⁹, hence, synchrony is a mechanism by which the parent’s mature physiological systems externally-regulate the child environment-dependent systems and tune them to social life. Here, we show that synchrony longitudinally shapes the neural basis of empathy in preadolescence and specifically targets brain areas that underpin the interface of cognitive and affective empathy.”

Levy, J., Goldstein, A. & Feldman, R. (2019). The neural development of empathy is sensitive to caregiving and early trauma. Nature Communications, 10, 1905.

6. “7-mo-old infants activate auditory and motor brain areas similarly for native and nonnative sounds; by 11–12 mo, greater activation in auditory brain areas occurs for native sounds, whereas greater activation in motor brain areas occurs for nonnative sounds, matching the adult pattern. We posit that hearing speech invokes an Analysis by Synthesis process: auditory analysis of speech is coupled with synthesis that predicts the motor plans necessary to produce it. Both brain systems contribute to the developmental transition in infant speech perception.”

Kuhl, P.K., Ramírez, R.R., Bosseler, A., Lin, J.L. & Imada, T. (2014). Infants’ brain responses to speech suggest analysis by synthesis. Proceedings of the National Academy of Sciences. 111(31) 11238-11245.

7. “The quality of the interactions between parents and their children, measured with gesture and speech, is associated with advanced language development … Infants’ language learning is enhanced in one-on-one social contexts, perhaps because these contexts allow more contingent social interaction between adult and child. … Evidence is accumulating to indicate a greater role for social interaction and social contingency in language learning. A large number of studies now suggest an important role for social behavior in language learning, among them: (1) the necessity of a social context for phonetic learning from exposure to a new language (Conboy & Kuhl, 2011; Kuhl et al., 2003); (2) the role of contingent response to infants’ babbling… (Goldstein et al., 2003; Goldstein & Schwade, 2008), (3) the role of social behavior (eye gaze) as a tactic that provides vital information for language learning in infants (Brooks & Meltzoff, 2008). … These findings contribute to our understanding of the social foundations of language, as observed in both typically developing and developmentally challenged young children, suggesting that language acquisition fundamentally requires social interaction to instigate learning (Kuhl, 2007; Kuhl, 2011; Kuhl, Coffey-Corina, Padden, Munson, Estes, & Dawson, 2013).”

Ramírez-Esparza, N., García-Sierra, A. & Kuhl, P.K. (2014). Look who’s talking: Speech style and social context in language input to infants is linked to concurrent and future speech development. In press: Developmental Science, 17(6), 880-91.

8. “Our findings, derived from the moment-to-moment tracking of eye gaze of one-year-olds and their parents as they actively played with toys, provide evidence for an alternative pathway, through the coordination of hands and eyes in goal-directed action. In goal-directed actions, the hands and eyes of the actor are tightly coordinated both temporally and spatially, and thus, in contexts including manual engagement with objects, hand movements and eye movements provide redundant information about where the eyes are looking. Our findings show that one-year-olds rarely look to the parent’s face and eyes in these contexts but rather infants and parents coordinate looking behavior without gaze following by attending to objects held by the self or the social partner. This pathway, through eye-hand coupling, leads to coordinated joint switches in visual attention and to an overall high rate of looking at the same object at the same time, and may be the dominant pathway through which physically active toddlers align their looking behavior with a social partner.”

^{Yu, C. & Smith, L.B. (2013). Joint attention without gaze following: Human infants and their parents coordinate visual attention to objects through eye-hand coordination. PLoS One, 8(11), e79659}.