Abstract
In recent years, a growing body of research has demonstrated that parents’ and children’s brains often exhibit neural similarity and synchrony during shared activities, emotional exchanges, and everyday interactions. This interbrain alignment offers a novel window into the mechanisms through which social connection, caregiving, and development unfold. In this review, we provide a comprehensive synthesis of studies investigating parent–child neural similarity and synchrony, drawing on diverse neuroimaging tools, including functional magnetic resonance imaging, functional near-infrared spectroscopy, and electroencephalography. To bring conceptual clarity to this rapidly growing field, we introduce a 2 × 2 framework that categorizes research contexts along two key dimensions: level of interaction (low vs. high) and emotional salience (low vs. high). Using this framework, we organize and interpret the empirical literature, highlighting consistent findings, methodological variations, and developmental implications across different types of parent–child engagement. This framework not only helps structure existing knowledge but also reveals context-specific understanding in the literature. Finally, we outline future directions that emphasize the importance of longitudinal designs, cultural diversity, multimodal imaging, and expanding beyond the dyadic unit. This review aims to deepen the understanding of how neural alignment within families supports learning, emotion regulation, and social development across the life span.
Introduction
Human development unfolds within relationships, and perhaps no relationship is more foundational than that between a parent and child. Across cultures, caregivers shape children’s cognitive, emotional, and social trajectories through countless shared moments—reading together, solving problems, playing, comforting, and simply being present. Recent advances in social and developmental neuroscience have provided new tools to investigate these interactions, revealing that such dyadic experiences are not only behavioral, physiological, and psychological but also neural (Figure 1). A growing number of studies now show that parents and children exhibit neural similarity—shared experience-shaped neural patterns in activation or connectivity—and neural synchrony—temporal alignment of brain activity during real-time interactions (e.g., Nam et al 2020; Birk et al 2022; Qu et al 2023; Alonso et al 2024; Haresign et al 2024; Zhao et al 2024). These discoveries open new avenues for understanding how relationships become biologically embedded and how social dynamics support or constrain development.
Parent–child similarity and synchrony at behavioral, physiological, psychological, and neural levels.
This review synthesizes the current research on parent–child neural similarity and synchrony, with three key aims. First, we provide an overview of the neuroimaging methods commonly used in this field, including functional magnetic resonance imaging (fMRI), functional near-infrared spectroscopy (fNIRS), and electroencephalography (EEG). Each of these methods offers unique strengths—whether in spatial precision, temporal resolution, or ecological flexibility—and together they create a rich methodological landscape for studying interbrain dynamics in families. Second, the literature on parent–child neural similarity and synchrony is diverse and fragmented in task designs. To address this fragmentation, we introduce a conceptual 2 × 2 framework that organizes studies along two key dimensions of task context: 1) the level of parent–child interaction (low vs. high) and 2) the emotional salience of the task (low vs. high). By mapping studies onto these two dimensions, the framework clarifies why different tasks and study designs may yield distinct patterns of neural similarity and synchrony, providing a coherent structure for understanding the field and guiding future research. This approach allows readers to see how neural alignment may emerge in different contexts—whether in low-interaction, low-emotion tasks, such as passive observation, or in high-interaction, emotionally intense tasks, such as conflict discussion—and highlights how task features shape both measurement and interpretation of interbrain dynamics. Third, we apply the 2 × 2 framework to review empirical findings, illustrating how parent–child dyads in different task designs give rise to neural similarity and synchrony within each quadrant. We highlight how neural similarity and synchrony are shaped by individual traits (e.g., attachment), contextual factors (e.g., parental stress), and developmental timing. Finally, we outline key future directions. We call for longitudinal and life span research to chart the developmental trajectory of neural alignment, greater methodological integration across imaging tools, inclusion of culturally and socioeconomically diverse samples, and the expansion of neural similarity and synchrony research beyond the parent–child dyad to include siblings, coparents, and multigenerational pairs. By framing neural similarity and synchrony not as isolated events but as core mechanisms in human development, this review aims to contribute a coherent structure to a burgeoning interdisciplinary field and to inspire research that better captures the relational brain in context.
Neuroimaging Methods for Assessing Parent–Child Neural Similarity and Synchrony
Research on parent–child neural similarity and synchrony relies on tools that can measure brain activity either simultaneously (for synchrony) or in parallel across separately scanned individuals (for similarity). Three primary neuroimaging methods, including fMRI, fNIRS, and EEG, have been most commonly used in this field. Each offers unique methodological advantages and constraints, shaping both the types of tasks that can be studied and the nature of the findings generated. In this section, we describe how each method has been applied to study parent–child neural similarity and synchrony, as well as evaluate their respective strengths and limitations.
fMRI
fMRI measures brain activity by detecting changes in blood oxygenation, providing high spatial resolution and the ability to localize activity in both cortical and subcortical structures. This technical feature makes fMRI especially valuable for identifying neural similarity—overlapping activation patterns across individuals when exposed to the same stimuli (e.g., during movie watching or emotional image processing). Accordingly, in parent–child research, fMRI has been used in both single-brain and dual-brain (hyperscanning) designs. For instance, studies have examined response pattern similarity (Figure 2A) between parent and child brain activation to emotionally salient stimuli (e.g., Lee et al 2018) or have assessed shared neural representations (Figure 2B) during naturalistic movie watching (e.g., Su et al 2023; Zhou et al 2023) or story listening (Habouba et al 2024). More recently, hyperscanning fMRI has enabled the simultaneous scanning of both members of a dyad, allowing examination of neural synchrony during interactive contexts such as parent–child conflict discussions (Ratliff et al 2021).
Common analytical approaches to measure parent–child neural similarity and synchrony in functional magnetic resonance imaging, functional near-infrared spectroscopy, and electroencephalography.
However, the same technical properties that confer strengths to fMRI also impose important constraints on its use in studying parent–child neural alignment. The relatively slow temporal resolution of the Blood-Oxygen-Level-Dependent (BOLD) signal limits sensitivity to rapid, moment-to-moment coordination, making fMRI better suited for capturing stable or trait-like neural similarity rather than fine-grained interactive synchrony. In addition, fMRI’s susceptibility to motion artifacts, high financial costs, and requirement for participants to remain still in a confined and noisy environment reduce its ecological validity and pose particular challenges for studies involving children. Consequently, while fMRI offers unparalleled spatial precision and access to deep brain structures such as the amygdala and hippocampus, it is less optimal for examining dynamic, real-world parent–child interactions, and hyperscanning applications remain technically demanding and relatively rare.
fNIRS
fNIRS measures cortical hemodynamic responses by detecting changes in oxygenated and deoxygenated hemoglobin using near-infrared light that penetrates the scalp and skull. Because near-infrared light can only reach superficial cortical tissue, fNIRS provides moderate spatial resolution restricted primarily to surface-level regions, particularly the prefrontal and temporoparietal cortices. At the same time, its lightweight, portable, and relatively motion-tolerant design makes fNIRS especially well suited for naturalistic and developmentally appropriate studies involving children. These technical characteristics have made fNIRS the dominant method for examining parent–child neural synchrony.
Most fNIRS studies employ hyperscanning designs to simultaneously record neural activity from both parent and child during real-time interactions, such as collaborative puzzle solving (Nguyen et al 2021b; Zhang et al 2024), joint drawing (Liu et al 2024), shared storybook reading (Zhai et al 2023), free verbal conversation (Nguyen et al 2021a), breastfeeding (Minagawa et al 2023), and unstructured play (Zhang et al 2024). A common analytic approach involves computing interpersonal wavelet transform coherence (Figure 2C), which capitalizes on fNIRS’s relatively high temporal sampling compared to fMRI and allows researchers to quantify time-locked synchrony between dyad members. Using these methods, studies have consistently reported increased parent–child neural synchrony in frontal and temporoparietal regions during cooperative and communicative contexts.
However, the same optical and hemodynamic characteristics that enable fNIRS’s ecological strengths also limit its application and interpretability. Because fNIRS cannot detect activity in deep cortical or subcortical regions, it is less suitable for examining neural similarity or synchrony involving affective and motivational systems such as the amygdala or ventral striatum. In addition, its spatial resolution is lower than that of fMRI, making it difficult to precisely localize neural sources or distinguish adjacent cortical regions. Signal quality can also be affected by extracerebral blood flow, hair density, or hair color, which may introduce noise or reduce data quality in some participants. Consequently, fNIRS is particularly powerful for capturing dynamic, real-time parent–child synchrony in naturalistic settings but less optimal for mapping whole-brain representations or deeper neural mechanisms underlying intergenerational alignment.
EEG
EEG records electrical activity from the scalp with millisecond-level temporal resolution, making it uniquely suited for capturing rapid neural dynamics underlying social interaction. Because EEG directly reflects neuronal firing rather than hemodynamic responses, it is particularly well suited for examining neural synchrony in the frequency domain (e.g., phase alignment of theta, alpha, or beta oscillations; Figure 2D) between two individuals (Haresign et al 2022; Turk et al 2022). These properties make EEG especially valuable for studying moment-to-moment coordination between parent and child. Accordingly, EEG has been widely used in hyperscanning studies examining interbrain synchrony during joint play, shared video viewing, and interactive games (Norton et al 2022; Zivan et al 2022; Bánki et al 2024; Deng et al 2024; Schwartz et al 2024). For example, Wass et al (2020) demonstrated that mother–child theta synchrony during cooperative tasks was associated with attachment security, while Leong et al (2017) showed that direct gaze enhanced adult–infant neural coupling, highlighting the role of social cues in shaping real-time neural alignment.
The technical strengths of EEG, such as its high temporal precision, portability, and tolerance for relatively naturalistic movement, make it especially well suited for capturing fast-changing, reciprocal processes that characterize parent–child interaction. Its low cost and scalability further support its widespread use in developmental and cross-cultural research. However, these advantages come with important limitations. EEG has relatively poor spatial resolution, making it difficult to localize neural sources or distinguish activity from neighboring cortical regions. It is also highly sensitive to motion artifacts and environmental noise, which can be especially challenging in studies involving young children. In addition, the interpretation of interbrain synchrony metrics (e.g., coherence or phase locking) is not always straightforward and may vary depending on analytic choices. As a result, while EEG excels at capturing real-time interpersonal dynamics, it is less well suited for identifying the specific neural structures underlying parent–child similarity or synchrony.
Taken together, these neuroimaging approaches offer unique and complementary strengths for studying parent–child neural similarity and synchrony, with each method best suited to distinct research questions and developmental contexts. fMRI is particularly well suited for examining representational similarity and the involvement of deep cortical and subcortical structures during individual or parallel processing. fNIRS, in contrast, is ideally positioned to capture interpersonal synchrony in ecologically valid, face-to-face interactions, especially in child-friendly settings. EEG excels in capturing rapid, moment-to-moment neural coupling and is uniquely suited for examining the temporal dynamics of social engagement. Increasingly, the field is moving toward multimodal approaches—such as combined EEG–fNIRS designs—that integrate the temporal precision of EEG with the spatial and ecological advantages of fNIRS. Selecting the most appropriate method, therefore, requires careful consideration of the research question, developmental population, and trade-offs among spatial resolution, temporal resolution, ecological validity, and susceptibility to motion. Progress in this area will depend on greater standardization of synchrony metrics, improved methodological transparency, and systematic efforts to examine convergence across modalities. Together, these advances will enable a more comprehensive understanding of how neural alignment supports social connection, learning, and emotional development within parent–child relationships.
A Framework for Synthesizing Research on Parent–Child Neural Similarity and Synchrony
Despite rapid growth in the field of interpersonal neuroscience, studies examining parent–child neural similarity and synchrony remain highly heterogeneous in their methods, task settings, and research questions. As a result, it can be challenging to synthesize findings across studies or identify the conditions under which neural alignment is most likely to emerge. To address this issue, we propose a
Taken together, these two dimensions generate four categories of parent–child engagement contexts (Figure 3). To enhance clarity and facilitate comparison across studies, we also provide a summary table (Table 1) that categorizes commonly used paradigms—including eye gaze, touch, co-viewing, cooperative tasks, and emotional discussions—along both dimensions.
A 2 × 2 framework for synthesizing research on parent–child neural similarity and synchrony by interaction level and emotional salience.
Categorization of Common Paradigms in the Study of Parent–Child Neural Similarity and Synchrony.
This framework serves several purposes. Theoretically, it clarifies the task-dependent nature of neural similarity and synchrony, highlighting that they are not fixed traits but dynamic, context-sensitive processes. For example, higher similarity and synchrony observed in one task (e.g., drawing together) may not generalize to another (e.g., watching emotional videos). Understanding these differences requires careful consideration of both the cognitive demands and emotional tone of each task. Methodologically, this framework helps researchers compare and interpret findings across diverse studies and identify gaps in the literature. For instance, while many studies have explored synchrony during collaborative tasks (high interaction, low emotion), fewer have focused on emotionally salient yet interactive contexts, such as grief processing or family conflict resolution. This framework also encourages researchers to design paradigms that move beyond artificial lab conditions to better reflect the rich emotional and relational experiences of real-world parent–child engagement.
Importantly, the framework can help advance the field by guiding the development of more ecologically valid, theory-driven, and developmentally appropriate research paradigms. It may also contribute to translational efforts: understanding which types of neural similarity and synchrony are most predictive of developmental outcomes—such as emotion regulation, learning, or resilience—may help identify targets for family-based interventions. For example, if neural synchrony during high-emotion, high-interaction tasks predicts child adaptive stress regulation, such contexts could be used in prevention and clinical work. Ultimately, this framework supports a more nuanced and integrative science of parent–child brain dynamics, encouraging future research to account for both the behavioral structure and emotional richness of family life.
In the following sections, we apply this 2-dimensional framework to organize and review empirical findings on parent–child neural similarity and synchrony (Table 2). By mapping existing studies onto this structure, we aim to provide a clearer synthesis of the diverse experimental paradigms used in the field. This approach highlights not only where and when parent–child neural alignment tends to emerge but also offers insight into the developmental functions it may serve across different contexts. In doing so, the framework helps illuminate patterns in the literature and reveals key gaps that future research can address.
Summary of Reviewed Studies Classified by Interaction Level × Emotional Salience.
dlPFC, dorsolateral prefrontal cortex; fMRI, functional magnetic resonance imaging; fNIRS, functional near-infrared spectroscopy.
Low Interaction + Low Emotional Salience
Low-interaction, low-salience contexts typically involve passive or co-experiential tasks with minimal emotional content. In fMRI research, parents and children generally engage in these nonemotional tasks—such as watching neutral videos or resting quietly—in separate scanning sessions, and neural similarity is subsequently computed by comparing their individually acquired brain activity patterns. In contrast, fNIRS and EEG studies typically involve parents and children completing comparable nonemotional tasks together in the same physical space, allowing researchers to assess neural synchrony through simultaneous recordings of both partners’ brain activity. These settings provide a baseline view of spontaneous neural similarity or synchrony that emerges in the absence of, or with only minimal, explicit interaction and affective arousal. By minimizing demands for communication or affective coordination, these settings allow researchers to examine the underlying neural similarity and synchrony that reflect enduring biological, relational, or environmental influences.
For example, Azhari et al (2019) used fNIRS hyperscanning to examine parent–child dyads during the co-viewing of neutral animation clips. They found modest levels of interpersonal neural synchrony in the medial prefrontal cortex (mPFC), a region associated with social cognition. However, this synchrony was significantly lower in parents who reported higher parenting stress, suggesting that even in nondemanding, emotionally neutral settings, family-level stress can dampen the natural alignment between parent and child brains. Similarly, recent fMRI work by Habouba et al (2024) examined neural similarity in parent–child dyads while parents and children separately listened to stories with no emotional content. The study demonstrated that biological parent–child dyads could be reliably identified from a larger group based on the similarity of their functional connectivity patterns during this passive, low-arousal activity. These “neural fingerprints” were evident across both cognitive and sensory networks, suggesting that even in contexts with low emotional salience, shared biological and relational histories shape stable patterns of brain activity.
In addition to these task-based findings, resting-state paradigms have offered additional evidence of the importance of neural similarity in children’s functioning, particularly in emotional, behavioral, and health-related outcomes. In 1 foundational study, Lee et al (2017a) found that greater similarity in resting-state networks between parents and adolescents, assessed using connectome similarity analysis, predicted higher emotional synchrony in daily life across 2 weeks (Figure 4). Moreover, this neural similarity was positively linked to adolescents’ emotional competence, suggesting that being neurally “in tune” with a parent confers regulatory advantages in navigating daily emotional experiences. Extending these findings to sleep, Lee et al (2017b) also showed that parent–child similarity in default mode network connectivity was associated with behavioral synchrony in sleep duration over a 2-week period, which in turn predicted better adolescent sleep quality. These findings suggest that resting-state neural connectivity similarity not only reflects intrinsic neural alignment, leading to shared behavioral rhythms, but also supports important developmental outcomes such as emotion regulation and sleep health.
An example illustrating the analysis and mechanistic implications of parent–child neural similarity in resting-state networks, which capture neural alignment that emerges in the absence of explicit interaction and affective arousal (i.e., Low Interaction + Low Emotional Salience). (A) Group-level intrinsic resting-state network (RSN) maps used to define network nodes for each participant. (B) Averaged RSN connectomes for the parent and child groups; dyadic connectome similarity was calculated for each parent–child pair. (C) Scatterplot showing association between dyadic connectome similarity and daily emotional synchrony. (D) Mediation model linking connectome similarity, daily emotional synchrony, and children’s emotional competence. Greater parent–child connectome similarity predicts higher emotional competence via daily emotional synchrony. *P < 0.05. Adapted with permission from Lee et al. (2017a).
Recent research has also begun to explore how intrinsic neural connectivity similarity at rest in parent–child dyads may buffer adolescents against environmental stress. In the study by Kim-Spoon et al (2024), high neural similarity between parents and adolescents served a protective role by attenuating the negative effects of household chaos on adolescent substance use. In contrast, when neural similarity was low, adolescents showed greater substance use over time, both directly and indirectly through reduced parental monitoring. In a related study, Clinchard et al (2024) found that greater family socioeconomic status predicted higher parent–child neural similarity, which was associated with enhanced adolescent-perceived parental monitoring and lower levels of substance use. These findings highlight neural similarity not only as a marker of interpersonal coordination but also as a potential neural foundation that supports adolescents in navigating environmental adversity.
Taken together, studies in low-interaction, low-salience settings suggest that even minimal co-experienced moments can uncover meaningful neural alignment between parents and children. Although the magnitude of synchrony or similarity is often lower in these passive contexts, the presence of such alignment likely reflects trait-like sources of alignment—such as shared genetics, long-term relational histories, or consistent environmental exposures—rather than moment-to-moment interpersonal coordination. These contexts offer a powerful lens into the quiet, often unnoticed neural signatures of connection that persist even when interaction is minimal, highlighting the subtle but enduring nature of the parent–child bond. This contrasts with emotionally intense or highly interactive tasks, where synchrony is typically more dynamic and sensitive to ongoing affective exchanges.
Low Interaction + High Emotional Salience
This category includes emotionally salient but low-interaction contexts, such as co-viewing emotionally evocative films or observing a child experiencing stress or discomfort. These settings allow researchers to investigate whether strong emotional stimuli alone—without the need for verbal communication or physical interaction—can drive shared neural responses between parents and children. The focus in these paradigms is not on task-based cooperation but on whether neural attunement occurs in response to shared emotional experiences and how such attunement might reflect or support family emotional processes and children’s adjustment.
Several studies using fMRI have begun to explore how parent–child neural similarity manifests in these emotionally salient yet passive contexts, revealing meaningful associations with adolescent well-being. In 1 study, Lee et al (2018) examined mother–child dyads in which adolescents underwent a stress-inducing task while mothers passively observed their child’s performance. Although there was no overall similarity in neural activation patterns across dyads, those who reported greater family connectedness exhibited higher representational similarity between maternal and adolescent brain activity in the anterior insula and dorsal anterior cingulate cortex (dACC) (Figure 5). Notably, increased neural similarity in these dyads was associated with reduced adolescent stress, suggesting that emotional closeness may enhance shared neural responses and, in turn, support youth’s emotional regulation during challenging experiences.
An example illustrating the analysis and mechanistic implications of mother–child neural similarity in a functional magnetic resonance imaging study in which adolescents completed a stress-inducing task while mothers passively observed their performance (i.e., Low Interaction + High Emotional Salience). (A) Averaged representational neural response pattern similarity matrices across dyads in the anterior insula and dorsal anterior cingulate cortex (dACC), shown separately by stressor condition. (B) Scatterplots showing the association between family connectedness and mother–child neural similarity in the anterior insula and dACC. (C) Scatterplots showing the association between dyadic neural similarity and adolescents’ stress. (D) Mediation model testing the indirect effect of family connectedness on adolescents’ stress via dyadic neural similarity. Greater family connectedness is associated with lower adolescent stress through greater mother–child neural concordance. *P < 0.05. **P < 0.01. Adapted with permission from Lee et al (2018).
Extending this line of inquiry, Zhou et al (2023) investigated parent–child neural similarity by having dyads separately watch an emotionally evocative animated film while undergoing fMRI. The study assessed the extent to which parents and children showed similar functional connectivity patterns between the emotion-related network and other brain regions in response to the film. Greater parent–child neural similarity during the movie-viewing session was linked to better emotional adjustment in youth, including lower levels of negative affect and anxiety and higher ego resilience. Importantly, these associations were observed only in families with higher levels of family cohesion, suggesting that the emotional quality of the parent–child relationship plays a key role in amplifying the benefits of shared neural processing during emotionally charged experiences.
Moreover, Su et al (2023) used fMRI to explore how family emotional climate shapes parent–child neural similarity during naturalistic movie watching. When watching a film depicting parent–child conflict, parent–child dyads exhibited higher neural similarity in mPFC regions compared to stranger–child dyads. However, in families characterized by negative emotional climates, the similarity in connectivity between the ventral mPFC and hippocampus was reduced. This diminished neural similarity mediated the link between negative family climate and increased internalizing symptoms in children, pointing to a neurobiological mechanism through which emotional discord in the family may affect children’s mental health.
Taken together, these findings highlight the power of emotionally charged shared experiences to elicit meaningful neural similarity between parents and children, even in the absence of active interaction. Importantly, the extent and developmental significance of this similarity appear to be strongly shaped by the emotional quality of the parent–child relationship. High levels of family cohesion and connectedness may foster greater neural alignment that promotes emotional adjustment, while negative emotional climates may impair this alignment, increasing vulnerability to internalizing symptoms. Emotionally salient but low-interaction contexts thus offer a unique and informative window into how the emotional tone of the family environment is embedded in brain-to-brain processes, with long-reaching implications for children’s well-being.
High Interaction + Low Emotional Salience
These contexts involve structured joint activities—such as problem-solving or cooperative play—that demand cognitive coordination but are not inherently emotionally charged. Unlike emotionally evocative or passive tasks, these interactions require real-time collaboration, mutual goal-setting, and continuous monitoring of each other’s actions, making them ideal for examining the cognitive mechanisms that support dyadic coordination. Researchers have increasingly turned to parent–child cooperative paradigms to explore how neural synchrony supports learning, executive functioning, and social engagement. These studies provide key insights into how cognitive alignment between parents and children is supported by brain-to-brain synchrony in specific prefrontal and temporoparietal regions.
Across multiple studies, structured yet emotionally neutral tasks such as joint problem-solving have consistently elicited parent–child interbrain synchrony in key cognitive control and social cognition regions, particularly the dorsolateral prefrontal cortex (dlPFC) and temporoparietal junction (TPJ). For instance, Reindl et al (2018) found that parent–child dyads exhibited increased neural synchrony in the dlPFC and frontopolar cortex during cooperative games (Figure 6), and this synchrony predicted better cooperation performance. Notably, only parent–child dyads—not those with strangers—showed this synchronization, and greater synchrony mediated links between parent and child emotion regulation, suggesting that even in nonemotional tasks, dyadic brain alignment may help foster affective development. Similarly, Miller et al (2019) showed that mother–child dyads demonstrated higher interbrain synchrony in the right dlPFC during cooperation than during independent tasks, with greater increases observed in mother–son pairs. Although the study did not find strong links between synchrony and attachment, the findings affirm that cooperation enhances shared neural dynamics.
An example of parent–child neural synchrony in a functional near-infrared spectroscopy (fNIRS) study, where parent–child dyads showed greater prefrontal coherence than stranger–child pairs during cooperation (i.e., High Interaction + Low Emotional Salience). (A) fNIRS cap configuration. Emitters are depicted as red circles, detectors as blue circles. The numbers indicate measurement channels. (B) Comparison between the coherence of random participant pairs and the task-related coherence of stranger–child competition (CompStr), stranger–child cooperation (CoopStr), parent–child competition (CompP), and parent–child cooperation (CoopP). Color indicates the t value, whereby more positive t values (red) indicate greater coherence. The numbers depict the measurement channels. Only coherence of CoopP in channels 8 and 12 was significantly higher than coherence of random pairs (indicated by the black circles), which most likely correspond to the dorsolateral prefrontal cortex (dlPFC) and frontopolar cortex (FPC). (C) Boxplots of the wavelet coherence in channels 8 and 12 in the 4 conditions. The mean coherence is represented by the triangle within the box. The red dashed line represents the coherence of random adult–child pairs in the respective channel. For both channels 8 and 12, a significant interaction of task and partner was observed, indicating a higher coherence in the CoopP condition. Adapted with permission from Reindl et al (2018).
Several other studies reveal similar findings using naturalistic and ecologically valid tasks. For example, Liu et al (2024) reported that parent–child dyads completing a collaborative Etch-A-Sketch drawing task showed increased interbrain synchrony in the dlPFC and TPJ. This synchrony was linked to greater shared affect, better collaboration, and higher levels of parental autonomy support and warmth. Using the same task, Xu et al (2025) found that the link between parent–child synchrony in the TPJ and observed parent–child interaction quality was moderated by parental emotional support. When support was high, neural synchrony predicted better interaction quality, whereas low support weakened or reversed this link. These findings underscore how the broader family context shapes the meaning and function of neural synchrony.
Similarly, Li et al (2023) demonstrated that children’s positive affect and parental praise during a collaborative tangram puzzle-solving task predicted greater parent–child synchrony in the dlPFC and TPJ, with the highest levels of synchrony observed when parental praise was paired with high levels of positive affect in the child. Moreover, dynamic patterns of synchrony changed over time and were related to children’s independent performance, indicating that the neural synchrony is sensitive to both affective state and performance-related cues. Focusing on fathers, Nguyen et al (2021b) found that father–child dyads also exhibit enhanced interpersonal neural synchrony in bilateral dlPFC and left TPJ during cooperative problem-solving, with fathers’ positive parenting attitudes associated with greater synchrony.
Together, these findings suggest that high-interaction, low-salience contexts reliably elicit neural synchrony in cognitive and social processing networks and that this synchrony reflects both real-time coordination and underlying relational quality. Although the tasks are not emotionally charged, they provide a valuable window into how parents and children co-construct shared goals and regulate behavior collaboratively. Neural synchrony in these contexts reflects more than mere cognitive alignment: it is shaped by relational quality, affective state, and parenting beliefs and practices. Such synchrony appears to serve both as a marker of successful interaction and as a potential mechanism for fostering positive developmental outcomes, particularly in executive function and emotion regulation.
High Interaction + High Emotional Salience
This final category captures emotionally intense interactions with high engagement, such as tasks that involve navigating frustration and recovery, discussing emotionally charged topics, or jointly managing strong emotions. These tasks not only demand cognitive coordination and sustained attention but also activate emotional brain systems, offering insight into how parents and children co-regulate under stress or deep emotional engagement. Because such tasks simulate real-life moments of challenge or support, they provide a rich context for understanding the interplay between affective regulation and interpersonal synchrony. They are particularly valuable for identifying risk and resilience processes in families facing adversity or raising emotionally vulnerable children.
A growing body of research has begun to explore how emotionally salient and interactive tasks elicit distinctive patterns of parent–child neural synchrony, especially in contexts involving stress, frustration, or emotional challenge. For example, Quiñones-Camacho et al (2020) investigated parent–child neural synchrony during a frustration–recovery paradigm using a stressful interactive task, which falls within the high-interaction, high–emotional salience dimension of our framework. They observed significant parent–child synchrony in dorsolateral and ventrolateral prefrontal regions during both the frustration and recovery phases (Figure 7). Moreover, neural synchrony during the frustration phase was positively associated with concurrent behavioral synchrony within parent–child dyads, highlighting the close correspondence between neural and behavioral coordination under emotional challenge.
An example of parent–child neural synchrony during a stressful frustration–recovery task assessed with functional near-infrared spectroscopy (i.e., High Interaction + High Emotional Salience). (A) Mean level of parent–child neural synchrony during the frustration and recovery phases, compared to the null distribution derived from permutation testing. (B) Association between parent–child neural synchrony during the frustration phase and concurrent behavioral synchrony. Adapted with permission from Quinones-Camacho et al (2020).
Importantly, subsequent work using the same paradigm demonstrated that contextual factors beyond the task itself shape neural synchrony in these emotionally charged interactions. Hoyniak et al (2021) found that greater environmental adversity (e.g., lower household income and higher levels of household chaos) predicted reduced behavioral synchrony, as well as diminished neural synchrony in dorsolateral and ventrolateral prefrontal regions. These findings suggest that chronic environmental stressors may undermine families’ capacity to achieve and sustain neural coordination during high-stress moments. Extending this line of research, Thompson et al (2025) employed a similar interactive stress task and showed that parent–child dyads exhibited significantly greater neural synchrony during stress relative to both baseline and recovery phases. Beyond mean-level differences, they further demonstrated that families characterized by greater balanced flexibility, reflecting healthy adaptability and cohesion, showed more dynamic modulation of frontal synchrony across baseline, stress, and recovery phases. Such flexibility in neural coordination may represent a key mechanism supporting effective family adaptation in the face of emotional challenge. Collectively, these studies highlight the importance of examining not only whether neural synchrony emerges under emotional challenge but also how it is shaped by broader environmental and family-level characteristics.
In addition to synchrony, recent research has begun to examine parent–child cross-brain connectivity (CBC), which is a related but distinct measure that captures concurrent and time-lagged links between neural activity in specific brain regions across dyadic members in high-interaction, high–emotional salience settings. Ratliff et al (2021) used an fMRI hyperscanning conflict discussion task and found evidence of CBC between emotion-related brain regions. Moreover, CBC was associated with parenting quality and adolescent depressive symptoms, suggesting that dynamic patterns of neural connectivity during emotionally charged interactions may reflect meaningful aspects of relational functioning and adolescent well-being. This work complements existing synchrony research by highlighting how specific neural connectivity patterns are implicated in emotion regulation and family risk processes, underscoring the unique value of fMRI in accessing subcortical affective regions (e.g., amygdala, hippocampus) that are typically beyond the reach of surface-level methods like fNIRS.
In sum, emotionally intense and interactive tasks provide a powerful lens into the dynamic, rapidly shifting nature of parent–child neural coordination. Unlike the more trait-like similarity and synchrony observed in low-interaction, low-salience contexts, neural alignment here reflects real-time co-regulation, affective engagement, and the dyad’s ability to jointly navigate emotional challenges. This synchrony tends to be more tightly tied to relational processes such as emotional support, conflict, and repair. These tasks thus provide unique insight into how families maintain emotional connection under stress and how neural alignment may support or undermine children’s regulatory development.
Unanswered Questions and Future Work
As research on parent–child neural similarity and synchrony continues to expand, the next frontier lies in deepening our understanding of what these phenomena represent, how they unfold over time, and how they interact with broader biological, relational, and cultural contexts. Future research on parent–child neural similarity and synchrony should go beyond demonstrating its presence to clarifying what it actually means for development, behavior, and relationships. Although studies increasingly document that parents and children show similar or synchronized neural activity in various interactive contexts, the field still lacks a clear theoretical and empirical understanding of what this alignment reflects. Does neural synchrony signify shared attention, emotional resonance, mutual prediction, or something else entirely? And are different forms of synchrony (e.g., in frontal versus temporal regions) associated with distinct relational processes? To answer these foundational questions, future research must move beyond simply demonstrating the presence of neural synchrony to systematically unpacking its meaning and mechanisms. The following directions highlight critical next steps toward achieving a deeper understanding of what parent–child neural similarity and synchrony truly signify (Figure 8).
Key directions for advancing the study of parent–child neural similarity and synchrony.
One important future direction is to adopt a life span and longitudinal perspective to investigate both the antecedents and consequences of parent–child neural similarity and synchrony, while considering key individual and contextual factors. Parenting styles, children’s gender, caregiver identity (e.g., mother versus father), primary caregiver status, socioeconomic background, and environmental adversity may all influence the development and outcomes of neural alignment (Hoyniak et al 2021; Endevelt-Shapira and Feldman 2023; Qu et al 2023; Liu et al 2024). Longitudinal studies tracking parent–child dyads across developmental stages, while systematically measuring these factors, can clarify how early neural similarity or synchrony emerges, what predicts its occurrence, and how it relates to later social, emotional, and cognitive outcomes (Nguyen et al 2021b). Such designs are critical not only for unpacking the temporal trajectories and developmental relevance of neural similarity and synchrony but also for examining how these individual and contextual factors may act as predictors or moderators, shaping the emergence, stability, and developmental consequences of parent–child neural alignment (Moffat et al 2024).
Expanding research to include culturally and relationally diverse samples is essential for building a more comprehensive and generalizable understanding of parent–child neural similarity and synchrony. Parenting styles, emotional expression, and relational norms differ widely across cultural contexts, which likely shape both the behavioral and neural substrates of parent–child interactions (Chen and Qu 2023). Moving beyond WEIRD (Western, Educated, Industrialized, Rich, Democratic) populations will help elucidate culturally specific patterns and universal principles of neural alignment in families (Qu et al 2021). Another exciting direction is to explore neural similarity and synchrony beyond the parent–child dyad. For example, Rogers et al (2020) showed that younger siblings became more behaviorally and neurally similar to their older siblings during risky decision-making after observing them, with increased similarity in regions such as the ventromedial prefrontal cortex, anterior insula, and ventral striatum. These findings suggest that neural similarity can emerge through social learning and modeling processes, in addition to shared environmental exposure and genetic relatedness. Moreover, emerging evidence indicates that mothers and fathers differ in neural synchrony with their children during shared experiences, with mothers exhibiting greater frontal neural synchrony than fathers during both passive video viewing and active play interactions (Liu et al 2024). Investigating similarity among siblings, co-parents, and multigenerational pairs can provide a more holistic view of how shared neural representations emerge within family systems (Dikker et al 2024; Liu et al 2024; Li et al 2025).
Methodologically, future studies should adopt multimodal neuroimaging approaches—such as fMRI, fNIRS, and EEG—not only to capitalize on the unique strengths of each technique, such as spatial precision in fMRI and high temporal resolution in EEG and fNIRS, but also to address the inherent limitations of any single modality. For instance, while fMRI offers detailed spatial information, it lacks the temporal resolution needed to capture rapid social exchanges; conversely, EEG and fNIRS provide finer-grained temporal data but more limited spatial localization. By integrating these methods, researchers can achieve a more comprehensive view of brain-to-brain similarity and synchrony that captures both where and when alignment occurs. Such multimodal designs allow for converging evidence and a more ecologically valid understanding of neural alignment during real-time, dynamic social interactions. This integrated approach is particularly valuable for tracing the temporal patterns of synchrony and for identifying how neural alignment varies across different contexts and developmental stages (Azhari et al 2022).
In parallel, advanced analytic approaches, including machine learning models and multibrain computational frameworks, are transforming how researchers quantify and interpret neural similarity and synchrony. Recent studies have begun applying machine learning to dyadic neuroimaging data, using techniques such as cross-brain neural pattern decoding, cross-dyad classification, and predictive modeling to identify features of brain-to-brain alignment that forecast relational behaviors or developmental outcomes (e.g., Kruse et al 2021; Gerloff et al 2022). These computational tools have the potential to enhance the precision with which researchers model how neural alignment unfolds over time and across diverse social contexts. Furthermore, multibrain computational frameworks allow researchers to model simultaneous activity across more than 2 individuals—for example, through multiperson hyperscanning analyses, group-level interbrain network modeling, and computational approaches that characterize emergent dynamics in triads, sibling groups, co-parenting pairs, and broader family or social systems (e.g., Czeszumski et al 2020; Liu et al 2021; De Felice et al 2025). These methods move beyond single-brain or dyadic designs to directly examine how multiple brains interact within shared environments. Collectively, these innovations support a systems-level understanding of social connectedness by revealing how neural dynamics emerge within and across dyads, triads, and larger relational structures.
Additionally, biological and clinical extensions of neural synchrony research hold significant promise for advancing both theory and application. Hormonal systems like oxytocin, genetic variations, and mental health indicators may shape or reflect an individual’s capacity for neural alignment with close others (Gvirts and Perlmutter 2020; Marzoratti et al 2023). These factors could serve as key moderators or mediators of synchrony and help identify mechanisms underlying relational well-being or dysfunction. Moreover, neural similarity and synchrony can reveal early biomarkers of risk for atypical socioemotional development and emerging psychopathology (Quiñones-Camacho et al 2022; Provenzi et al 2023). For example, Zhang et al (2024) demonstrated that children with oppositional defiant disorder (ODD) and their mothers showed lower neural synchrony across multiple tasks (i.e., free play, positive, and negative discussions) compared to typically developing dyads. These differences spanned a wide range of frontal, parietal, and temporal regions and were linked to symptom severity, pointing to potential neural markers of clinical vulnerability that may inform early identification and intervention.
Finally, by proposing a 2 × 2 framework that situates parent–child neural similarity and synchrony along dimensions of interaction level and emotional salience, this review suggests that different forms of neural alignment may index distinct developmental processes depending on task context. Neural similarity observed in low-interaction contexts may reflect more stable, trait-like alignment shaped by shared biology and cumulative relational experience, whereas neural synchrony during highly interactive, emotionally salient contexts may reflect more dynamic, state-dependent processes supporting real-time co-regulation and interpersonal engagement. This distinction, which is not readily apparent in prior narrative accounts that treat neural alignment as a unitary construct, points to important directions for future work. In particular, it will be essential to examine whether neural similarity and synchrony observed across task contexts follow distinct developmental trajectories, recruit partially overlapping or dissociable neural systems, differ in their sensitivity to interactional and emotional demands, and carry differential implications for children’s socioemotional adjustment. Addressing these questions will be critical for refining theories that specify when, how, and why different forms of neural alignment support social bonding, learning, and regulation across development.
In sum, future research must broaden developmental and cultural perspectives through longitudinal and diverse samples, as well as use multimodal neuroimaging along with advanced analytic methods. These directions will enhance understanding of neural similarity and synchrony in the family, strengthening the depth and increasing the generalizability of findings across populations and life stages. Together, these efforts will provide critical insights into the meaning of parent–child neural similarity and synchrony.
Footnotes
Funding
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by funding from the National Science Foundation (BCS 1944644); the Society for Research in Child Development Small Grants Program for Early Career Scholars; the Center for Culture, Brain, Biology, and Learning at Northwestern University (to YQ); and a research award by the Virginia Tech Institute for Society, Culture and Environment (to T-HL).
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.