The Development of Infant Temperamental Fear and Baseline RSA: Bidirectional Associations with Maternal Internalizing Symptoms

• In Event: The Multilevel Factors Influencing the Development of Temperament

Abstract

The first two years of life are a critical period for capturing social influences on the development of temperamental fear (Gartstein et al., 2010) and PNS activity (Mulkey & Plessis, 2019). However, less is known regarding the co-development of infant fear and baseline respiratory sinus arrhythmia (RSA) across the first two years of life, and the role that maternal internalizing symptoms may play. Early individual differences, such as parasympathetic nervous system (PNS) activity and fearful temperament, are thought to mediate intergenerational associations between maternal and child internalizing symptoms, (de Vente et al., 2020). The present study examined associations between maternal internalizing symptoms, infant temperamental fear and infant respiratory sinus arrhythmia (RSA) using a random-intercepts cross-lagged panel model (RI-CLPM). We examined baseline RSA as it reflects an individual’s capacity for physiological regulation and is not context specific (Porges, 2007).

212 mother-infant pairs (51% female) participated in a longitudinal, multi-site study. Mothers self-reported internalizing symptoms using the Beck Anxiety Inventory and the Beck Depression Inventory (Steer & Beck, 1997; Beck et al., 1996) when infants were 4, 8, 12, and 18-months and also reported on their infants’ temperament using the Fear subscale on the Infant Behavior Questionnaire (Putnam et al., 2014). We also collected ECG during a 4-minute baseline at the latter 3 time points.

The RI-CLPM fit the data well (Figure 1), χ2 = 30.96, p = .02, CFI = 0.96, RMSEA = .06, SRMR = .04. Intercept factors in a RI-CLPM account for trait-like levels. The intercept of maternal internalizing was significantly associated with the intercept of fear, β=-0.33, p < .01. In addition, the intercepts of maternal internalizing and baseline RSA was approaching significant, β=-0.21, p = .08.

Autoregressive paths demonstrated stability in maternal internalizing symptoms across time. However, there was weaker within-person stability in infant fear and infant baseline RSA, with some stability earlier in infancy that no longer held from 12 to 18M.

Cross-lagged paths demonstrate transactional associations between the variables of interest. Greater maternal internalizing symptoms at 4M predicted greater infant fear at 8M, though this association was not present at later timepoints. In addition, there were also infant-directed effects on maternal internalizing symptoms as both infant fear and baseline RSA at 8M predicted maternal internalizing at 12M, although 12M fear and RSA do not predict maternal internalizing symptoms at 18M.

Taken together, results highlight the importance of considering transactional processes during infancy when examining the influence of maternal internalizing symptoms on the development of individual differences in temperamental fear and physiology. Specifically, bidirectional influences occur during the first year of life, suggesting this may be a sensitive period for the development of fear in the context of maternal internalizing symptoms. While maternal internalizing may influence infant fear, greater infant fear and higher baseline RSA also reinforce the presence of greater maternal internalizing symptoms during this infancy period. These findings may provide evidence of a possible mechanism by which intergenerational associations of internalizing symptoms may develop within families.

Authors

• Anna M Zhou, University of Utah
  Presenting Author

• Elizabeth Youatt, Pennsylvania State University, University Park
  Non-Presenting Author

• Koraly Elisa Perez-Edgar, Pennsylvania State University, University Park
  Non-Presenting Author

• Vanessa Lobue, Rutgers University
  Non-Presenting Author

• Kristin A. Buss, Pennsylvania State University, University Park
  Non-Presenting Author