Skip to main content
NCBI home page
NIHPA Author Manuscripts logoLink to NIHPA Author Manuscripts
. Author manuscript; available in PMC: 2026 Jun 3.
Published before final editing as: Dev Psychol. 2026 Jun 1:10.1037/dev0002203. doi: 10.1037/dev0002203

Greater Mother-Infant Synchrony Predicts Less Positive Emotion in Infants at High Levels of Maternal Anxiety

Emily L Mallin 1, JungWon Choi 2, Aliuna Schorn-Pagel 3, Chloe Van Noy 4, Abigail S Varghese 5, Kylie N McDaniel 6, Elizabeth J Kiel 7, Rebecca J Brooker 8
PMCID: PMC13227913  NIHMSID: NIHMS2165150  PMID: 42224004

Abstract

High levels of mother-infant neural synchrony in the first year of life are traditionally linked to positive socioemotional outcomes for infants, while low synchrony relates to more negative outcomes. However, the notion of synchrony as universally beneficial draws largely from studies involving mothers at low risk for psychopathology. Theories of mothers as scaffolds for development suggests that synchrony with a dysregulated mother may be less beneficial for developing infants. In a sample (N = 62 dyads) at elevated risk for anxiety problems, we tested whether mother-infant synchrony differentially predicted infant outcomes as a function of maternal symptoms. Synchrony indexed at infant age 1 using EEG recordings interacted with mothers’ self-reported worry-based anxiety symptoms to predict positivity such that at high maternal anxiety, greater synchrony was associated with less infant positivity, but synchrony was unrelated to infant positivity when maternal anxiety symptoms were low.

Results are consistent with previous notions that there are ideal levels of synchrony between mothers than infants, and that maternal anxiety, in particular, may diminish the putative benefits of synchrony for infants’ socioemotional development. This work lays the foundation for greater nuance in subsequent investigations of synchrony in infant development.

Historically, a defining feature of synchrony has been a temporal match in the responses of individuals to the same event (Feldman, 2007). Applications of synchrony in studies of human infants are believed to take on three prototypical forms, one of which is the co-occurrence of states between parent and child. Measures of neural synchrony, which quantify this co-occurring state at the level of neural function, offer information about the physiological systems that facilitate the coordination and contingencies of social behaviors that are critical for the formation of high-quality relationships (Hasson et al., 2012; M. Nguyen et al., 2019; T. Nguyen et al., 2020).

In mother-infant dyads, greater neural synchrony in the first year of life, purportedly reflecting greater mother-infant attunement, is linked to higher-quality social bonds (Kinreich et al., 2017), better emotion regulation (Koole & Tschacher, 2016), and more positive social, affective, and cognitive development (Feldman, 2012). In contrast, low levels of neural synchrony are associated with less-optimal parenting behaviors, like intrusiveness (Endevelt-Shapira & Feldman, 2023), and insecure attachment representations in children (Nguyen et al., 2024). However, the prevalent notion that neural synchrony is universally beneficial draws primarily from studies of dyads in which infants have mothers with low levels of risk for psychopathology. Given the premise that synchrony with mothers establishes a foundation for infants’ subsequent expectations for future behaviors and interactions with social partners, it stands to reason that synchrony with mothers who are prone to dysregulation may be less beneficial for infants than synchrony with well-regulated mothers. Although such a possibility is critical to a comprehensive understanding of synchrony, it has not been empirically tested, particularly at the level of neural function.

To date, most research on mother-infant synchrony has focused on behavioral synchrony, reporting synchronous interactions with mothers as linked to more positive social-emotional outcomes in children (Bell, 2020), better recognition of mothers’ faces (Thompson & Trevathan, 2009), lower levels of aggression (Harrist et al., 1994), and greater social competence (Harrist et al., 1994). Though behavioral findings have advanced the field in critical ways, relatively recent hyperscanning methods, involving the simultaneous collection of neurophysiological data from two individuals (Montague et al., 2002), offer insight into the neurophysiological foundations that may support mother-infant synchrony and uniquely predict infant-mother dynamics. Studies using electroencephalography (EEG) or Functional Near Infrared Spectroscopy (fNIRS) to quantify synchronized fluctuations in mother-infant neural activity predict dyadic attachment characteristics even in the absence of links to behavior (Nguyen et al., 2024). Though behavioral and neural synchrony are linked (Neel et al., 2025), the value added for assessing synchrony at even general levels of neural function (e.g., cortical activity) may be particularly salient during infancy, when behaviors are generally less coordinated overall, relative to older children.

Yet, opportunities exist to examine synchronous neural processing with even more specificity. EEG recordings can be time-locked to target neural processing associated with specific events. For example, the Late Positive Potential (LPP) is visible as a positive deflection in the time-locked EEG waveform, which is larger for affectively arousing images relative to neutral images (Cuthbert et al., 2000a). Because the LPP can be used to index individual differences in emotional reactivity, its simultaneous assessment in infant-mother dyads, now supported by the development of an infant LPP paradigm (Choi et al., in prep), can offer information about synchrony during a specific neural process linked to emotion.

Regardless of measurement strategy, there exists a historical tendency to assume that “more is better” when it comes to mother-infant synchrony, with rare exception. A global focus on the benefits of mother-infant synchrony for infant development likely results from a grounding of prior work in theory that portrays mothers as “more knowledgeable others” (Vygotsky, 1978) from whom infants learn skills, including the self-regulation of emotion. Indeed, there is now decades of work framing mothers as the scaffolds for the development of regulatory skills (Kopp, 1982), and suggesting that infants’ modeling and eventual adoption of skills they see and learn from well-regulated mothers supports healthy long-term socioemotional development.

Though we do not disagree with these classic models, we recognize that they contain an implicit assumption that mothers are well-regulated despite a substantial number of mothers struggling with dysregulation. Postpartum anxiety affects more than 12% of women worldwide and even more experience subclinical symptoms (range: 37.5% - 100%; Brok et al., 2017; Miller et al., 2021). Even at nonclinical levels, anxiety is hallmarked by dysregulated emotions, including increased negativity and diminished positivity (Hofmann et al., 2012). Maternal anxiety is often expressed through persistent worry, a central cognitive feature of anxiety that is highly prevalent among mothers and foundational to generalized anxiety disorder (American Psychiatric Association, 2013; Brok et al., 2017b). Prior work further indicates that maternal anxiety symptoms are negatively associated with infant positive affect (Coplan et al., 2005) and predict dysregulated fear and worry in toddlers (Kiel et al., 2021), underscoring the relevance of examining both positive and negative dimensions of infant socioemotional functioning in relation to maternal anxiety.

Is it possible, then, that synchrony with an anxious mother may not be beneficial for emotional development in offspring? Synchrony appears to be stronger for infants and anxious mothers relative to non-anxious mothers (Beebe et al., 2011; Smith et al., 2022), as less anxious mothers move in and out of synchronous periods based on child arousal while more anxious mothers adopt less-contingent patters of interaction and appear less able to downregulate arousal in response to child distress. This pattern of results is consistent with a notion of anxious mothers as less sensitive (Nicol-Harper et al., 2007) and more intrusive (Kiel & Kalomiris, 2016). Though demonstrating differences in degree of synchrony, rather than consequence, this pattern is also consistent with a position that there may be optimal levels of synchrony (Nguyen et al., 2024), implicating the need for empirical tests outside of the “more is better” approach. Despite this potentially critical nuance in our understanding of the limits to the benefits of mother-infant synchrony, work that has directly tested this question, particularly with regard to emotion processing, remains limited.

To address this important gap in the current literature, we tested, in a sample at high risk for anxiety problems, whether maternal worry-based symptoms of anxiety moderated longitudinal links between synchrony in mother-infant emotion processing and positive and negative socioemotional outcomes in infants. Outcomes focused on internalizing behaviors and positive emotion given their previously established associations with maternal anxiety; as both represent potential avenues of risk, we tested internalizing behaviors and positive emotion as separate outcomes, aiming for a conceptual replication of our primary hypothesis. Finally, consistent with a notion of optimal levels of synchrony, we included nonlinear terms in our statistical models. We hypothesized that high levels of synchrony would predict positive infant outcomes (low internalizing, high positive emotion) when maternal symptoms were low, but that this effect would be attenuated and then reversed as maternal symptoms increased.

Method

Participants

Data were collected between 2021 and 2025 as part of a longer, longitudinal study of emotional development in mothers and infants. Mothers and their infants (N = 171 dyads) were recruited from southeast Texas via social media advertisements, community recruitment events, and targeted mailings. The larger study included a second data collection site that did not use a hyperscanning approach. Thus, data from only one site is included in the current work. Target sample size was based on a power analysis for the larger study. Data were collected from infants and mothers when infants were 1 (M = 12.70 months, SD = 1.87) and 2 (M = 24.00 months, SD = 1.36) years old. In total, 171 infants (49.71% female) and their biological mothers (100% female) participated. Most mothers identified as White (80.12%), 5.85% as Black or African American, 5.85% as mixed race, 3.51% as Asian, 0.58% as American Indian/Alaska Native, 0.58% as Native Hawaiian/Pacific Islander, and 1.75% as other, while 1.75% did not report their race. Almost a quarter of mothers (22.22%) were of Hispanic/Latino ethnicity. A roughly similar proportion of infants were White (74.85%), 14.04% were mixed race, 2.92% were Black or African American, 2.34% were Asian, 2.34% were reported as other, and 3.51% of infants had no race reported. Roughly a quarter (25.73%) of infants were of Hispanic/Latino ethnicity. Most families (86.07%) were retained from Age 1 to Age 2.

At the time of recruitment, mothers and infants were screened for probable risk for anxiety difficulties in the dyad. Levels of worry-based anxiety symptoms in mothers was reported by mothers using the Penn State Worry Questionnaire (PSWQ; Meyer et al., 1990) and levels of fear-based anxiety risk in infants was assessed using a 5-item wariness scale (Buss, 2011) and the internalizing scale of the Infant Toddler Social Emotional Assessment (ITSEA; Carter et al., 2003). This strategy has been previously used to recruit samples elevated in risk for anxiety problems (Buss, 2011). Overall, 41.9% of mothers met criteria for elevated anxiety risk based on PSWQ scores above 51 (corresponding to the 80th percentile in community samples; (Gillis et al., 1995), 7% of infants met criteria for elevated anxiety risk based on endorsing 4 out of 5 wariness items or an internalizing T-score of 60 or higher, and 14% of dyads met criteria for elevated risk in both the mother and infant.

Procedures

One week before a laboratory visit at infant age 1, mothers were emailed a set of online questionnaires to complete (Qualtrics XM). Following written consent from mothers on the day of the laboratory visit, mothers and infants participated in several standardized behavioral paradigms after which EEG data were collected. This project focuses on survey and EEG data given our hypotheses about mother-infant neural synchrony. Online questionnaires were again completed by mothers online when infants were 2 years old.

Measures

Maternal Anxiety Symptoms

Worry-based symptoms of maternal anxiety were assessed at study enrollment (child age 1) using the PSWQ, which asked mothers to rate, on a 5-point scale, the degree to which 16 items were characteristic of them (1 = not at all typical, 5 = very typical). Symptoms of worry were prioritized given their high prevalence in mothers (Brok et al., 2017) and their role as the cardinal feature of generalized anxiety disorder (American Psychiatric Association, 2013). Scores from individual items were mean composited (⍺ = .93), resulting in an overall score for which higher values indexed higher levels of maternal anxiety. Mean scores were used in place of sum scores to keep the range and variance of the scale in line with other study variables. Because the mean score is a linear transformation of the sum score (i.e., all totals are divided by the number of items), the mean and sum scores are perfectly correlated.

Synchrony

During the laboratory visit at child age 1, infants were seated in their mother’s lap approximately 24” from the center of a computer screen. A pleasant sound and animated, high-contrast image were presented for 1000 ms to capture infants’ attention. Once infants were focused on the computer screen, experimenters manually advanced the paradigm to present a series color photographs of 10 angry and 10 neutral women’s faces from the NimStim Stimulus set (Tottenham et al., 2009). A full outline of the task is provided in Appendix A. Images were presented in color at a resolution of 1024 × 768 pixels and displayed for 2000 ms, and were shown in a randomized order for 40 trials divided into two blocks (20 trials each), with a break in between. Mothers were instructed to remain focused and watch the screen for the duration of the task.

Continuous EEG was recorded simultaneously from mothers and infants at 32 electrode sites, arranged per the 10/20 labeling system, using the BrainVision actiCHamp Plus (BrainVision, LLC) recording system. Data were sampled at a rate of 500 Hz and referenced to electrode CP2. For mothers, electrooculogram (EOG) data were recorded from four passive electrodes placed above and below the left eye and on the outer canthi of each eye. In infants, ocular artifacts were determined through examination of the Fp2 electrode.

EEG data were preprocessed offline using BrainVision Analyzer 2.0. Following the interpolation of bad channels, electrodes were re-referenced to the whole head average, high-pass filtered at 0.1 Hz, and low-pass filtered at 20 Hz. Trials were segmented (−200 to 1500 ms) and baseline corrected for 200 ms before faces appeared. Artifacts were identified when one of the following criteria was met: a difference of 150 μV within 200 ms, a voltage step of more than 75 μV between data points, amplitudes below .05 μV within a 50 ms period, or activity that exceeded +100 μV or −100 μV.

To quantify mother-infant neural synchrony, we calculated the maximum cross-correlation between mothers’ and infants’ LPP time series. This method captures both the strength and temporal alignment of neural responses, which allow for potential delays in infant processing relative to maternal responses. Synchrony analyses were conducted using responses to angry face trials only. Angry trials were selected because they have been shown to elicit greater arousal and discomfort in infants (Kobiella et al., 2008) and greater emotional arousal compared to neutral stimuli (Cuthbert et al., 2000b). LPP time series were extracted from electrode Pz for mothers and electrode Oz for infants, focusing on the 300 to 1000 ms post-stimulus window. For mothers, time windows and electrode sites were selected based on previous literature (MacNamara et al., 2016; Nyman et al., 2020). For infants, a dearth of prior work with infants led to electrode sites selection being guided by visual inspection of the observed scalp distribution and literature from older children. Using the LPP time series, we computed cross-correlations of LPP amplitudes for each dyad. The maximum correlation coefficient within the defined lag window was used as the measure of mother-infant neural synchrony.

Infant Socioemotional Outcomes

Infant internalizing behaviors were quantified at child ages 1 and 2 using maternal report on the internalizing scale of the ITSEA, which asks parents to rate, on a 3-point Likert scale (1= not true/rarely; 3 = very true/often), the degree to which behaviors and characteristics were true for their infant (e.g., seems nervous, tense or fearful). Individual items (n = 30) were mean composited (⍺ = .88); higher scores indicated more internalizing behaviors.

Infant positive emotion was quantified at ages 1 and 2 using maternal report on the pleasure scale of the Toddler Behavior Assessment Questionnaire – Revised (TBAQ-R; Goldsmith, 1996), a 110-item survey that asks parents to rate, on a 7-point Likert scale (1= Never; 7 = Always), the degree to which behaviors are true for their child (e.g., when playing quietly with one of her/his favorite toys, how often did your child smile). Individual items (n = 10) were mean composited (⍺ = .75), with higher values indicating more positivity.

Missing Data

Because our primary analysis regarded synchrony, only dyads for whom usable EEG data was collected from both mother and infant were included. Of the 172 recruited dyads, EEG data were not collected from 72 at age 1 (35 did not enroll until age 2, 28 did not attend the age 1 visit or had yet completed their visit at the time these data were analyzed, 9 completed only questionnaires). Among whom participated at Phase 1, sixty-nine dyads were excluded because EEG data were not available from both members of the dyad. The most common reason for missing EEG data was that the child pulled off the cap, became distressed during, or otherwise rejected the capping (n = 30). Other reasons for missing EEG data included excessive artifacts in the recording (n = 10), a technical error resulting in no flags in the data for one or both participants (n = 7), insufficient trials to average after data cleaning (n = 6), mothers ending the visit early (n = 5) mothers declining EEG data collection (n = 4), babies falling asleep during the assessment (n = 2), experimenter error (n = 2), a head circumference that was too large for available caps (n = 2), and a baby being sent home before data collection because they were sick (n = 1).

Among the remaining 66 dyads with usable EEG data from both dyad members, patterns of missingness in questionnaire data were not significantly different from a missing completely at random pattern (Little’s MCAR χ2(24) = 23.8, p = .47). Four dyads were excluded as multivariate outliers, yielding a final analytic sample of 62 dyads. Of these 62 dyads, 9.68% (n = 6) did not complete the TBAQ and the ITSEA at infant age 1, and 32.26% (n = 20) did not complete the TBAQ-R and the ITSEA at age 2. Thus, missing data were handled using a Full Information Maximum Likelihood (FIML) procedure, which is appropriate for data missing at random (Enders, 2010).

Plan for Analysis

Analyses were conducted as path models in Mplus Version 8. In an effort at conceptual replication, infant internalizing symptoms and positive affect were tested in separate models. For each model, centered maternal anxiety was used as a predictor along with linear and quadratic terms for synchrony and the interactions between maternal anxiety and the linear and quadratic synchrony variables. Age 1 measures were used as covariates for a rigorous test of age 2 outcomes. Given our small sample size and our directional, theory-driven hypotheses, we conducted follow-up analyses for interactions that emerged as significant (p < .05) or of marginal significance (p < .10). To probe significant interactions, simple slopes were examined at ± 2SD of maternal anxiety, which allowed us to characterize effects at more extreme levels of anxiety within this high-risk sample. Two SD was selected because it aligned “high levels” with the highest scores in our data set (and on the measure) and “low levels” with the lowest scores in our data set (and on the measure).

Transparency and Openness

Data and syntax that support the conclusions of this work are available through the Open Science Framework at: https://osf.io/afu6d/?view_only=17c9c69e532148538a5a69bd83b06597. This study was not preregistered.

Results

On average, synchrony was low to moderate (Table 1), ranging from −0.01 to 0.33. Maternal anxiety scores were also moderate, with substantial variability across participants (range: 1.25 to 4.88). Approximately 51.3% of mothers scored above 51 on the PSWQ, corresponding to the 80th percentile in community samples and indicating elevated levels of worry (Gillis et al., 1995). Infant internalizing problems were relatively low on average, whereas positive affect was moderately high. Bivariate correlations among variables were nonsignificant except for maternal-reported emotion. A visual inspection of the data suggested that, on average, maximum synchrony was observed at a lag of approximately 100 ms following picture presentation, with infants’ responses typically trailing behind their mothers’ (Figure 1).

Table 1.

Descriptive Statistics and Bivariate Correlations among Study Variables

Variables Descriptive statistics Bivariate correlations
M SD Min Max 1 2 3 4 5
1. Mother-Infant Neural Synchrony 0.12 0.08 −0.01 0.33
2. Maternal Anxiety Symptoms 3.13 0.84 1.25 4.88 .12
3. Infant Internalizing Behavior Age 1 0.41 0.20 0.07 0.90 −.05 .13
4. Infant Positivity Age 1 4.77 0.81 2.33 6.29 .20 .01 −.35**
5. Infant Internalizing Behavior Age 2 0.44 0.21 0.17 0.97 −.09 .17 .64*** −.27
6. Infant Positivity Age 2 5.06 0.64 3.90 6.80 .16 .13 −.37* .53*** −.33*
Open in a new tab

Note. Maternal anxiety (PWSQ) was rated on a 1–5 scale, internalizing problems on a 0–2 scale, and pleasures on 1–7 scale.

*

p < .05.

**

p < .01.

***

p < .001.

Figure 1.

Figure 1.

Open in a new tab

Grand-Average Cross-Correlation Time Course Across Mother-Infant Dyads

Aligned with primary hypothesis, we first tested whether linear and quadratic synchrony interacted with maternal anxiety symptoms to predict infant internalizing behaviors at age 2 (Table 2), while controlling for internalizing behaviors at age 1. Infant internalizing at age 1 significantly predicted age 2 internalizing (B = 0.70, SE = 0.12, 95% CI [0.29, 0.79], p < .001). The interaction between quadratic synchrony and maternal anxiety symptoms was marginally significant (B = 1.73, SE = 1.00, 95% CI [−0.23, 3.70], p = .08). However, follow-up analyses returned nonsignificant simple slopes at low (B = −2.45, SE = 3.71, 95% CI [−7.77, 5.78], p =. 51), mean (B = 0.45, SE = 3.40, 95% CI [−6.21, 7.11], p = .90), and high (B = 3.35, SE = 3.87, 95% CI [−5.04, 8.84], p = .39) levels of maternal anxiety, suggesting the interaction reflected a reversal in direction, but nonsignificant effects at each level (Figure 2).

Table 2.

Results of Regression Analyses Predicting Infant Age 2 Internalizing

Internalizing Behavior Age 2
B SE 95% CI β
Infant Internalizing Age 1 0.70*** 0.12 0.46, 0.94 .67
Linear Neural Synchrony −0.11 0.26 −0.62, 0.40 −.04
Quadratic Neural Synchrony 0.45 3.40 −6.21, 7.11 .02
Maternal Anxiety Symptoms 0.04 0.04 −0.03, 0.11 .16
Linear Neural Synchrony × Maternal Anxiety 0.79 0.60 −0.39, 1.96 .22
Quadratic Neural Synchrony × Maternal Anxiety 1.73+ 1.00 −0.23, 3.70 .05
R2 = .46, p < .001
Open in a new tab
+

p < .10.

***

p < .001.

Figure 2.

Figure 2.

Open in a new tab

Interaction between Maternal Anxiety and Neural Synchrony Predicting Infant Internalizing Behaviors

We next tested whether linear and quadratic synchrony interacted with maternal anxiety symptoms to predict infant positivity (Table 3), while controlling for positivity at age 1. Infant positivity at age 1 significantly predicted age 2 positivity (B = 0.54, SE = 0.13, 95% CI [0.29, 0.79], p < .001). Linear synchrony and maternal anxiety symptoms interacted to predict infant positive affect (B = −2.84, SE = 1.03, 95% CI [−4.86, −0.82], p < .01). Follow-up analyses showed that at high maternal anxiety, greater synchrony was associated with less infant positivity (B = −6.22, SE = 2.91, 95% CI [−11.92, −0.52], p < .05). Effects at mean (B = −1.48, SE = 1.72, 95% CI [−4.86, 1.90], p = .39) and low (B = 3.26, SE = 1.85, 95% CI [−0.36, 6.88], p = .07) levels were not significant. (see Figure 3).

Table 3.

Results of Regression Analyses Predicting Infant Age 2 Positivity

Positivity Age 2
B SE 95% CI β
Infant Positivity Age 1 0.54*** 0.13 0.29, 0.79 .62
Linear Neural Synchrony −1.48 1.72 −4.86, 1.90 −.17
Quadratic Neural Synchrony 6.42 11.07 −15.27, 28.12 .08
Maternal Anxiety Symptoms 0.08 0.07 −0.07, 0.22 .09
Linear Neural Synchrony × Maternal Anxiety −2.84** 1.03 −4.86, −0.82 −.24
Quadratic Neural Synchrony × Maternal Anxiety 2.00 2.07 −2.06, 6.05 .02
R2 = .48, p < .001
Open in a new tab
**

p < .01.

***

p < .001.

Figure 3.

Figure 3.

Open in a new tab

Interaction between Maternal Anxiety and Neural Synchrony in Predicting Infant Positivity

To provide transparency regarding statistical power following a number of marginal effects, we conducted a post-hoc power analysis. Results indicated that the present sample size provided adequate power to detect medium-to-large effects (f2 = 0.25), but power was limited for detecting small effects.

Discussion

Our results were largely consistent with the idea that associations between mother-infant neural synchrony and infant emotion outcomes may be contingent upon mothers’ levels of anxiety symptoms. When levels of maternal anxiety symptoms were relatively high, greater neural synchrony was related to less pleasure in infants, but this putatively maladaptive pattern was eliminated as levels of maternal anxiety symptoms declined. This pattern of association is consistent with the possibility that synchrony with a mother who is high in symptoms of anxiety, and likely dysregulated herself, may lead to less optimal socioemotional outcomes for infants. One explanation for blunted positivity can be drawn directly from the aforementioned sociocultural perspectives in infant development. From this view, infants learn to mirror and then adopt the emotion tendencies of caregivers (Vygotsky, 1978) who serve as scaffolds for infant development (Kopp, 1989). To the extent that synchrony reflects alignment in the mother-infant dyad and anxious mothers are, themselves, less prone to displays of positivity (Whaley et al., 1999), this effect may outline a pattern whereby high levels of synchrony are linked to parallel propensities for dysregulated affect in mothers and infants.

A second possible explanation can be drawn from the fields of mother-infant attachment and emotion regulation. Positive emotion displays in infants can serve the purpose of eliciting sensitive interactions with caregivers (Stern et al., 2023). However, inconsistent or insensitive maternal responsiveness, such as that often attributed to anxious mothers (Beebe et al., 2011; Jones et al., 2021), can lead to infants “giving up” on trying to elicit maternal interactions (Ainsworth et al., 1978). A similar pattern has been reported for infants of depressed mothers, who show more blunted interactional styles with adults more broadly (Field, 2018), presumably reflecting what infants have learned about the nature of social interactions with their own mothers. As difficulties with social interaction comprise a risk factor for anxiety problems in childhood (Rubin et al., 2009), this dysregulated tendency may comprise a dysregulated behavior that contributes to children’s own risk.

Though lower levels of anxiety symptoms in mothers eliminated the link between synchrony and blunted positivity, as expected, it is somewhat puzzling that we did not see the traditional effect by which greater synchrony is associated with better infant outcomes (e.g., more positivity, less internalizing) when maternal symptoms are low (Feldman, 2012; Kinreich et al., 2017; Koole & Tschacher, 2016). Such a pattern is consistent with a critical role for caregivers in the modeling and scaffolding of healthy emotion expression and regulation (Lincoln et al., 2017) and protection against the development of internalizing difficulties (Kovacs & Devlin, 1998; Shaw et al., 1997). There are at least three possible reasons this effect may not have been observed. First, a linear association may have been absent because our high-risk sample offered a more-than-typical amount of information about low levels of synchrony and high levels of maternal anxiety, diminishing an overall linear effect. Indeed, average levels of mother-infant synchrony in our sample could best be described as moderate. Second, our measure of synchrony is not directly comparable to past studies, particularly those using observed behavior, as it is focused on a specific process of emotion processing at the neural level. It is possible that different levels of analysis will contain unique patterns of association. A linear pattern of effects may be more easily detected in behavioral studies, which analyze the actual behaviors to which a dyadic partner will respond. In contrast, a study such as ours may be more closely tapping into emotion propensities that will or will not be directly linked to observed behavior, outlining a more complex process of interplay between parent and child. Finally, it is difficult to say the degree that our results truly replicate previous work (or not) given that very little work has included nonlinear terms in tests of links between synchrony and infant outcomes when maternal symptoms are accounted for.

Yet, a potentially informative pattern emerged suggesting that maternal anxiety symptoms may also moderate the relation between synchrony and infant internalizing. The direction of the association between synchrony and infant internalizing behaviors appears to reverse as maternal anxiety symptoms increase. Even so, a precise interpretation of this effect is limited by a marginal interaction and nonsignificant simple slopes, likely because the variance in infant internalizing symptoms at infant age 2 was low. Yet, the presence of the interaction effect suggests to us that there is a critical role for consideration of the primary developmental windows for outcomes of interest. Negative outcomes in the form of blunted positivity may emerge earlier than internalizing problems because positivity itself is both earlier-developing and easily observed at age 2 (Sullivan & Lewis, 2003). Infants’ adoption of dysregulatory strategies may also become more apparent across the second year of life, as co-regulatory interactions move from parent-led (asymmetrical) to shared (symmetrical) interactions (Aureli et al., 2022). Thus, significant patterns of association with internalizing problems may emerge later, as variability in internalizing behaviors increases in its on critical window. Rerunning analyses as our longitudinal cohort ages will be a high priority for future work.

Of additional potential interest for future work may be to test whether our design, which included seating infants on mothers’ laps, may have had a direct effect on levels of synchrony. There is evidence that proximity and touch may increase levels of neural synchrony between caregivers and younger infants (4–6 months; Nguyen et al., 2021), which would result is slightly elevated levels of attunement for mothers and infants in our sample. The degree to which maternal touch remains associated with synchrony over time, or may itself be moderated by individual difference characteristics, is a ripe area for further inquiry.

Finally, this work could be extended to other prototypes of synchrony, such as sequential relations between the behaviors or states of partners or ongoing lagged associations in a stream of parent-child behaviors (Feldman, 2007). Because this type of follow up work may be helpful in determining whether maternal symptoms are more likely to disrupt state matching, temporal dynamics, or both, it could be particularly useful for highlighting specific processes that may be targeted for intervention.

Despite its contributions, this study is not without limitations. First, dependence on simultaneous, clean ERPs from mothers and infants limited our final sample size, potentially obscuring small effects. Second, we relied on maternal reports of both anxiety symptoms and infant emotion. Although our EEG-based measure of synchrony lessens concerns about findings due solely to overlapping method variance, subsequent work should also include observational measures of infant emotion characteristics. In addition, future research should examine whether other dimensions of maternal anxiety, beyond worry-based symptoms, show similar or distinct associations with mother-infant neural synchrony. Third, although our sample is relatively diverse and enriched for anxiety symptoms, most mothers did not meet clinical thresholds for a likely anxiety diagnosis. It will be important for follow-up work to be conducted in clinical samples, which may be better designed to reveal full crossover effects of synchrony and maternal anxiety as predictors of infant outcomes. Fourth, Although the sample included reasonable ethnic diversity (one quarter of infants and mothers identified as Hispanic/Latinx), the generalizability of findings may be diminished by limited numbers of participants who identified their as non-White. Fifth, our framework is grounded in an assumed foundational role of social interactions between mothers and infants. However, all mothers and infants were genetically related in our sample; as such, the possibility that results reflect a common genetic-based lability in mothers and infants cannot be ruled out. Sixth, we want to be clear that although ours is a study of mothers and infants, we find it unlikely that results reflect an exclusively maternal effect. Given the theoretical grounding, it is equally plausible that a similar pattern of results would be observed for fathers who serve as primary caregivers, similar to most mothers in our sample.

In addition, although angry faces are emotionally salient for both mothers and infants, they may engage partially distinct processing mechanisms across development. Accordingly, identical stimuli may not elicit fully shared interpretations across dyad members. Finally, given recent critiques (Levy et al., 2021), we note that we have not yet been able to overlay our neural synchrony measure with observed behaviors. Although we do have measures of behavioral outcomes, some caution may still be warranted for assumptions about how synchrony may overlap with the regulatory behaviors for which they are theoretically foundational (Feldman, 2007, 2012).

Despite limitations, our work provides a foundation and highlights potential avenues for additional investigations of nuance in traditional interpretations of mother-infant synchrony. Results offer empirical evidence for the notion that the benefits of mother-infant synchrony may be limited, and even related to risk, in some contexts, including those characterized by maternal anxiety.

Public Significance Statement:

Although the field has traditional considered the attunement of emotional behaviors between mothers and infants to be beneficial, this work demonstrates that there may be limits to these benefits. Specifically, if a high risk for anxiety is present, infants show less positivity when they are attuned to mothers, suggesting they may not benefit in the same way as would be expected based on previous work.

Acknowledgments

Research reported in this manuscript was supported by the National Institute of Mental Health under award numbers R01MH113669 and S1R01MH113669. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Appendix A. Description of the Infant Emotional Face Task

Task Overview

The infant emotional faces task was designed to elicit sustained attention to emotionally salient stimuli and to parallel paradigms previously used to examine the Late Positive Potential (LPP) in older children (Kujawa et al., 2012). Facial stimuli were drawn from the NimStim Sitmulus set of Facial Expressions (Tottenham et al., 2009). Infants were seated on their mother’s lap approximately 24” from a computer monitor. Mothers were instructed to remain neutral and attend to the screen while holding their infant facing forward.

Stimuli

Stimuli consisted of color photographs of adult women displaying angry (n = 10) or neutral (n = 10) facial expressions. Images were presented at a resolution of 1024 × 768 pixels and centered on a neutral background. Images included actors from three races (White, Asian, and Black/African-American); all children saw neutral and angry faces from all three races. Angry expressions were selected because they are highly emotionally salient (Cuthbert et al., 2000) and reliably elicit arousal and discomfort during infancy (Kobiella et al., 2008).

Trial Structure and Attention Monitoring

The task consisted of 40 total trials presented across two blocks (20 trials per block). Angry and neutral faces were presented in pseudorandom order. Each trial was presented in the following order: First a fixation cross was presented on the screen for 500 ms. Then, an animated, high contrast video of shapes (Figure 1) was presented along with a short but pleasant audio sequence for 1000 ms to capture infant attention to the screen. Once a trained experimenter, monitoring in real time, visually confirmed that the infant was attending to the screen, they advanced the computer to a face stimulus. The face stimulus (angry or neutral) was then presented for 2000 ms. Short breaks were provided between blocks as needed.

Figure 1.

Figure 1.

Open in a new tab

Emotional Face Task

Contributor Information

Emily L. Mallin, Texas A&M University

JungWon Choi, Texas A&M University.

Aliuna Schorn-Pagel, Texas A&M University.

Chloe Van Noy, Texas A&M University.

Abigail S. Varghese, Texas A&M University

Kylie N. McDaniel, Texas A&M University

Elizabeth J. Kiel, Miami University

Rebecca J. Brooker, Texas A&M University

References

  1. Ainsworth MDS, Blehar MC, Waters E, & Wall S (1978). Patterns of attachment: A psychological study of the strange situation (pp. xviii, 391). Lawrence Erlbaum. [Google Scholar]
  2. American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition). American Psychiatric Association. 10.1176/appi.books.9780890425596 [DOI] [Google Scholar]
  3. Aureli T, Presaghi F, & Garito MC (2022). Mother–infant co-regulation during infancy: Developmental changes and influencing factors. Infant Behavior and Development, 69, 101768. 10.1016/j.infbeh.2022.101768 [DOI] [PubMed] [Google Scholar]
  4. Beebe B, Steele M, Jaffe J, Buck KA, Chen H, Cohen P, Kaitz M, Markese S, Andrews H, Margolis A, & Feldstein S (2011). Maternal anxiety symptoms and mother–infant self- and interactive contingency. Infant Mental Health Journal: Infancy and Early Childhood, 32(2), 174–206. 10.1002/imhj.20274 [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Bell MA (2020). Mother-child behavioral and physiological synchrony. In Benson JB (Ed.), Advances in Child Development and Behavior (Vol. 58, pp. 163–188). JAI. 10.1016/bs.acdb.2020.01.006 [DOI] [PubMed] [Google Scholar]
  6. Brok EC, Lok P, Oosterbaan DB, Schene AH, Tendolkar I, & van Eijndhoven PF (2017a). Infant-Related Intrusive Thoughts of Harm in the Postpartum Period: A Critical Review. The Journal of Clinical Psychiatry, 78(8), e913–e923. 10.4088/JCP.16r11083 [DOI] [PubMed] [Google Scholar]
  7. Brok EC, Lok P, Oosterbaan DB, Schene AH, Tendolkar I, & van Eijndhoven PF (2017b). Infant-Related Intrusive Thoughts of Harm in the Postpartum Period: A Critical Review. The Journal of Clinical Psychiatry, 78(8), e913–e923. 10.4088/JCP.16r11083 [DOI] [PubMed] [Google Scholar]
  8. Brooker R, Choi J, & Mallin EL (2026, April 7). Greater Mother-Infant Synchrony Predicts Less Positive Emotion in Infants at High Levels of Maternal Anxiety. Retrieved from osf.io/afu6d [DOI] [PMC free article] [PubMed]
  9. Buss KA (2011). Which fearful toddlers should we worry about? Context, fear regulation, and anxiety risk. Developmental Psychology, 47(3), 804–819. 10.1037/a0023227 [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Carter AS, Briggs-Gowan MJ, Jones SM, & Little TD (2003). The Infant-Toddler Social and Emotional Assessment (ITSEA): Factor structure, reliability, and validity. Journal of Abnormal Child Psychology, 31(5), 495–514. 10.1023/a:1025449031360 [DOI] [PubMed] [Google Scholar]
  11. Coplan R, O’Neil K, & Arbeau K (2005). Maternal anxiety during and after pregnancy and infant temperament at three months of age. Journal of Prenatal & Perinatal Psychology & Health, 19, 199–215. [Google Scholar]
  12. Cuthbert BN, Schupp HT, Bradley MM, Birbaumer N, & Lang PJ (2000a). Brain potentials in affective picture processing: Covariation with autonomic arousal and affective report. Biological Psychology, 52(2), 95–111. 10.1016/S0301-0511(99)00044-7 [DOI] [PubMed] [Google Scholar]
  13. Cuthbert BN, Schupp HT, Bradley MM, Birbaumer N, & Lang PJ (2000b). Brain potentials in affective picture processing: Covariation with autonomic arousal and affective report. Biological Psychology, 52(2), Article 2. 10.1016/S0301-0511(99)00044-7 [DOI] [PubMed] [Google Scholar]
  14. Endevelt-Shapira Y, & Feldman R (2023). Mother–Infant Brain-to-Brain Synchrony Patterns Reflect Caregiving Profiles. Biology, 12(2), 284. 10.3390/biology12020284 [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Feldman R (2007). Parent–infant synchrony and the construction of shared timing; physiological precursors, developmental outcomes, and risk conditions. Journal of Child Psychology and Psychiatry, 48(3–4), 329–354. 10.1111/j.1469-7610.2006.01701.x [DOI] [PubMed] [Google Scholar]
  16. Feldman R (2012). Parent-infant synchrony: A biobehavioral model of mutual influences in the formation of affiliative bonds. Monographs of the Society for Research in Child Development, 77(2), 42–51. 10.1111/j.1540-5834.2011.00660.x [DOI] [Google Scholar]
  17. Field T (2018). Postnatal anxiety prevalence, predictors and effects on development: A narrative review. Infant Behavior and Development, 51, 24–32. 10.1016/j.infbeh.2018.02.005 [DOI] [PubMed] [Google Scholar]
  18. Gillis M, Haaga D, & Ford G (1995). Normative Values for the Beck Anxiety Inventory, Fear Questionnaire, Penn State Worry Questionnaire, and Social Phobia and Anxiety Inventory. Psychological Assessment, 7, 450–455. 10.1037/1040-3590.7.4.450 [DOI] [Google Scholar]
  19. Goldsmith HH (1996). Studying Temperament via Construction of the Toddler Behavior Assessment Questionnaire. Child Development, 67(1), 218–235. 10.1111/j.1467-8624.1996.tb01730.x [DOI] [PubMed] [Google Scholar]
  20. Harrist AW, Pettit GS, Dodge KA, & Bates JE (1994). Dyadic synchrony in mother–child interaction: Relation with children’s subsequent kindergarten adjustment. Family Relations: An Interdisciplinary Journal of Applied Family Studies, 43(4), 417–424. 10.2307/585373 [DOI] [Google Scholar]
  21. Hasson U, Ghazanfar AA, Galantucci B, Garrod S, & Keysers C (2012). Brain-to-Brain coupling: A mechanism for creating and sharing a social world. Trends in Cognitive Sciences, 16(2), 114–121. 10.1016/j.tics.2011.12.007 [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Hofmann SG, Asnaani A, Vonk IJJ, Sawyer AT, & Fang A (2012). The Efficacy of Cognitive Behavioral Therapy: A Review of Meta-analyses. Cognitive Therapy and Research, 36(5), 427–440. 10.1007/s10608-012-9476-1 [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Jones LB, Hall BA, & Kiel EJ (2021). Systematic review of the link between maternal anxiety and overprotection. Journal of Affective Disorders, 295, 541–551. 10.1016/j.jad.2021.08.065 [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Kiel EJ, & Kalomiris AE (2016). Correlates and consequences of toddler cortisol reactivity to fear. Journal of Experimental Child Psychology, 142, 400–413. 10.1016/j.jecp.2015.08.006 [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Kiel EJ, Price NN, & Buss KA (2021). Maternal Anxiety and Toddler Inhibited Temperament Predict Maternal Socialization of Worry. Social Development (Oxford, England), 30(1), 258–273. 10.1111/sode.12476 [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Kinreich S, Djalovski A, Kraus L, Louzoun Y, & Feldman R (2017). Brain-to-Brain Synchrony during Naturalistic Social Interactions. Scientific Reports, 7(1), 17060. 10.1038/s41598-017-17339-5 [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Kobiella A, Grossmann T, Reid VM, & Striano T (2008). The discrimination of angry and fearful facial expressions in 7-month-old infants: An event-related potential study. Cognition and Emotion, 22(1), 134–146. 10.1080/02699930701394256 [DOI] [Google Scholar]
  28. Koole SL, & Tschacher W (2016). Synchrony in Psychotherapy: A Review and an Integrative Framework for the Therapeutic Alliance. Frontiers in Psychology, 7, 862. 10.3389/fpsyg.2016.00862 [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Kopp CB (1982). Antecedents of self-regulation: A developmental perspective. Developmental Psychology, 18(2), 199–214. 10.1037/0012-1649.18.2.199 [DOI] [Google Scholar]
  30. Kopp CB (1989). Regulation of distress and negative emotions: A developmental view. Developmental Psychology, 25(3), 343–354. 10.1037/0012-1649.25.3.343 [DOI] [Google Scholar]
  31. Kovacs M, & Devlin B (1998). Internalizing disorders in childhood. Journal of Child Psychology and Psychiatry, and Allied Disciplines, 39(1), 47–63. [PubMed] [Google Scholar]
  32. Kujawa A, Klein DN, & Hajcak G (2012). Electrocortical reactivity to emotional images and faces in middle childhood to early adolescence. Developmental Cognitive Neuroscience, 2, 458–467. 10.1016/j.dcn.2012.03.005 [DOI] [PMC free article] [PubMed] [Google Scholar]
  33. Levy J, Lankinen K, Hakonen M, & Feldman R (2021). The integration of social and neural synchrony: A case for ecologically valid research using MEG neuroimaging. Social Cognitive and Affective Neuroscience, 16(1–2), 143–152. 10.1093/scan/nsaa061 [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Lincoln CR, Russell BS, Donohue EB, & Racine LE (2017). Mother-child interactions and preschoolers’ emotion regulation outcomes: Nurturing autonomous emotion regulation. Journal of Child and Family Studies, 26(2), 559–573. 10.1007/s10826-016-0561-z [DOI] [Google Scholar]
  35. MacNamara A, Kotov R, & Hajcak G (2016). Diagnostic and symptom-based predictors of emotional processing in Generalized Anxiety Disorder and Major Depressive Disorder: An event-related potential study. Cognitive Therapy and Research, 40(3), Article 3. 10.1007/s10608-015-9717-1 [DOI] [PMC free article] [PubMed] [Google Scholar]
  36. Meyer TJ, Miller ML, Metzger RL, & Borkovec TD (1990). Development and validation of the penn state worry questionnaire. Behaviour Research and Therapy, 28(6), 487–495. 10.1016/0005-7967(90)90135-6 [DOI] [PubMed] [Google Scholar]
  37. Miller HN, LaFave S, Marineau L, Stephens J, & Thorpe RJ (2021). The impact of discrimination on allostatic load in adults: An integrative review of literature. Journal of Psychosomatic Research, 146, 110434. 10.1016/j.jpsychores.2021.110434 [DOI] [PMC free article] [PubMed] [Google Scholar]
  38. Neel ML, Jeanvoine A, Kjeldsen CP, & Maitre NL (2025). Mother–Infant Dyadic Neural Synchrony Measured Using EEG Hyperscanning and Validated Using Behavioral Measures. Children, 12(2), 115. 10.3390/children12020115 [DOI] [PMC free article] [PubMed] [Google Scholar]
  39. Nguyen M, Vanderwal T, & Hasson U (2019). Shared understanding of narratives is correlated with shared neural responses. NeuroImage, 184, 161–170. 10.1016/j.neuroimage.2018.09.010 [DOI] [PMC free article] [PubMed] [Google Scholar]
  40. Nguyen T, Abney DH, Salamander D, Bertenthal BI, & Hoehl S (2021). Proximity and touch are associated with neural but not physiological synchrony in naturalistic mother-infant interactions. NeuroImage, 244, 118599. 10.1016/j.neuroimage.2021.118599 [DOI] [PubMed] [Google Scholar]
  41. Nguyen T, Kungl MT, Hoehl S, White LO, & Vrtička P (2024). Visualizing the invisible tie: Linking parent–child neural synchrony to parents’ and children’s attachment representations. Developmental Science, 27(6), e13504. 10.1111/desc.13504 [DOI] [PubMed] [Google Scholar]
  42. Nguyen T, Schleihauf H, Kayhan E, Matthes D, Vrtička P, & Hoehl S (2020). The effects of interaction quality on neural synchrony during mother-child problem solving. Cortex, 124, 235–249. 10.1016/j.cortex.2019.11.020 [DOI] [PubMed] [Google Scholar]
  43. Nicol-Harper R, Harvey AG, & Stein A (2007). Interactions between mothers and infants: Impact of maternal anxiety. Infant Behavior and Development, 30(1), 161–167. 10.1016/j.infbeh.2006.08.005 [DOI] [PMC free article] [PubMed] [Google Scholar]
  44. Nyman T, Pegg S, Kiel EJ, Mistry-Patel S, Becker-Schmall LJ, & Brooker RJ (2020). Perceived social support moderates neural reactivity to emotionally valenced stimuli during pregnancy. Psychophysiology, 57(11), Article 11. 10.1111/psyp.13647 [DOI] [PMC free article] [PubMed] [Google Scholar]
  45. Rubin KH, Coplan RJ, & Bowker JC (2009). Social Withdrawal in Childhood. Annual Review of Psychology, 60(Volume 60, 2009), 141–171. 10.1146/annurev.psych.60.110707.163642 [DOI] [PMC free article] [PubMed] [Google Scholar]
  46. Shaw DS, Keenan K, Vondra JI, Delliquardi E, & Giovannelli J (1997). Antecedents of preschool children’s internalizing problems: A longitudinal study of low-income families. Journal of the American Academy of Child & Adolescent Psychiatry, 36(12), 1760–1767. 10.1097/00004583-199712000-00025 [DOI] [PubMed] [Google Scholar]
  47. Smith MR, Parrish KH, Shimomaeda L, Zalewski M, Rosen ML, Rodman A, Kasparek S, Mayes M, Meltzoff AN, McLaughlin KA, & Lengua LJ (2022). Early-childhood temperament moderates the prospective associations of coping with adolescent internalizing and externalizing symptoms. Frontiers in Psychology, 13, 1011095. 10.3389/fpsyg.2022.1011095 [DOI] [PMC free article] [PubMed] [Google Scholar]
  48. Stern JA, Kelsey CM, Krol KM, & Grossmann T (2023). Maternal recognition of positive emotion predicts sensitive parenting in infancy. Emotion, 23(5), 1506–1512. 10.1037/emo0001125 [DOI] [PMC free article] [PubMed] [Google Scholar]
  49. Sullivan MW, & Lewis M (2003). Emotional Expressions of Young Infants and Children: A Practitioner’s Primer. Infants & Young Children, 16(2), 120. [Google Scholar]
  50. Thompson LA, & Trevathan WR (2009). Cortisol Reactivity, Maternal Sensitivity, and Infant Preference for Mother’s Familiar Face and Rhyme in 6-Month-Old Infants. Journal of Reproductive and Infant Psychology, 27(2), 143–167. 10.1080/02646830801918463 [DOI] [PMC free article] [PubMed] [Google Scholar]
  51. Tottenham N, Tanaka JW, Leon AC, McCarry T, Nurse M, Hare TA, Marcus DJ, Westerlund A, Casey BJ, & Nelson C (2009). The NimStim set of facial expressions: Judgments from untrained research participants. Psychiatry Research, 168(3), 242–249. 10.1016/j.psychres.2008.05.006 [DOI] [PMC free article] [PubMed] [Google Scholar]
  52. Vygotsky LS (1978). Mind in Society: Development of Higher Psychological Processes. Harvard University Press. 10.2307/j.ctvjf9vz4 [DOI] [Google Scholar]
  53. Whaley SE, Pinto A, & Sigman M (1999). Characterizing interactions between anxious mothers and their children. Journal of Consulting and Clinical Psychology, 67(6), 826–836. 10.1037/0022-006X.67.6.826 [DOI] [PubMed] [Google Scholar]

RESOURCES