Aggression is a transdiagnostic indicator that permeates nearly all psychiatric disorders in youth (Kazdin, Reference Kazdin2003). It represents one of the most common reasons children are referred for mental health treatment (Kazdin, Reference Kazdin2003), and its persistence is linked to severe and intractable trajectories of mental illness (Loeber & Hay, Reference Loeber and Hay1997; Ostrov & Houston, Reference Ostrov and Houston2008; Schaeffer, Petras, Ialongo, Poduska, & Kellam, Reference Schaeffer, Petras, Ialongo, Poduska and Kellam2003), as well lower academic achievement, substance use, and incarceration (Huesmann, Dubow, & Boxer, Reference Huesmann, Dubow and Boxer2009; Kokko, Tremblay, Lacourse, Nagin, & Vitaro, Reference Kokko, Tremblay, Lacourse, Nagin and Vitaro2006; Tremblay et al., Reference Tremblay, Nagin, Seguin, Zoccolillo, Zelazo, Boivin and Japel2004). Theory and research highlight the impact of maternal invalidation on child aggression (Calkins & Hill, Reference Calkins, Hill and Gross2007; Hajal & Paley, Reference Hajal and Paley2020; Morris, Criss, Silk, & Houltberg, Reference Morris, Criss, Silk and Houltberg2017; Ramsden & Hubbard, Reference Ramsden and Hubbard2002), and suggest that its influence may vary based on differences in child physiological reactivity (Ellis & Boyce, Reference Ellis and Boyce2008), another known risk factor for aggression (Hubbard et al., Reference Hubbard, Smithmyer, Ramsden, Parker, Flanagan, Dearing and Simons2002; Lorber, Reference Lorber2004; Scarpa & Raine, Reference Scarpa and Raine1997). Moreover, these effects may be particularly pronounced among children of mothers with emotion regulation (ER) difficulties (Buckholdt, Parra, & Jobe-Shields, Reference Buckholdt, Parra and Jobe-Shields2014; Hajal & Paley, Reference Hajal and Paley2020; Rutherford, Wallace, Laurent, & Mayes, Reference Rutherford, Wallace, Laurent and Mayes2015), underscoring the importance of examining these factors in at-risk children, before the emergence of serious mental illness. Thus, to refine etiological models and improve prevention efforts, the current study tested the independent and interactive effects of maternal invalidation and child physiological reactivity on aggression among at-risk preschool-aged children.
Maternal invalidation and risk for aggression
Theories about aggression highlight maternal invalidation as a critical risk factor (Calkins & Hill, Reference Calkins, Hill and Gross2007; Hajal & Paley, Reference Hajal and Paley2020; Morris et al., Reference Morris, Criss, Silk and Houltberg2017; Ramsden & Hubbard, Reference Ramsden and Hubbard2002). Maternal invalidation refers to communications that emotional experiences or expressions of emotion are inappropriate, invalid, or unwanted (Eisenberg, Cumberland, & Spinrad, Reference Eisenberg, Cumberland and Spinrad1998). When parents invalidate their child's emotions, they may respond by dismissing or minimizing emotional experiences (e.g. telling child to change their emotional experience, ‘don't be angry’), by magnifying or intensifying the emotion (e.g. yelling back, getting angry), and/or or by punishing the expression of emotion (e.g. mocking the emotional experience). To the child, these responses provide immediate feedback about the (un)acceptability of emotions, shaping the way in which emotions are understood, experienced, and expressed in the future (Eisenberg et al., Reference Eisenberg, Cumberland and Spinrad1998; Morris et al., Reference Morris, Criss, Silk and Houltberg2017; Morris, Silk, Steinberg, Myers, & Robinson, Reference Morris, Silk, Steinberg, Myers and Robinson2007). This transactional process may be particularly consequential when socializing negative emotions (Eisenberg, Fabes, & Murphy, Reference Eisenberg, Fabes and Murphy1996), given the centrality of the dysregulation of negative emotion to aggression (Scarpa, Haden, & Tanaka, Reference Scarpa, Haden and Tanaka2010; Vitaro, Barker, Boivin, Brendgen, & Tremblay, Reference Vitaro, Barker, Boivin, Brendgen and Tremblay2006).
Indeed, links between maternal invalidation of negative emotion and aggression have been shown across development, with research documenting associations in childhood (e.g. Brown, Fitzgerald, Shipman, & Schneider, Reference Brown, Fitzgerald, Shipman and Schneider2007; Chang, Schwartz, Dodge, & McBride-Chang, Reference Chang, Schwartz, Dodge and McBride-Chang2003), and adolescence (e.g. Buckholdt et al., Reference Buckholdt, Parra and Jobe-Shields2014; Byrd, Vine, Frigoletto, Vanwoerden, & Stepp, Reference Byrd, Vine, Frigoletto, Vanwoerden and Stepp2022b). Although theory and research point to the preschool period as particularly sensitive to these maternal influences (Cole, Lougheed, & Ram, Reference Cole, Lougheed, Ram, Cole and Hollenstein2018), very little work has focused on elucidating risk pathways during this developmental window. The preschool period is characterized by marked neurobiological changes that underlie notable shifts in emotional and behavioral regulation (Brown & Jernigan, Reference Brown and Jernigan2012; Garon, Bryson, & Smith, Reference Garon, Bryson and Smith2008), highlighting the potential importance of clarifying etiological mechanisms early in development, before trajectories of severe mental illness emerge.
Physiological reactivity and risk for aggression
Research suggests that children with heightened physiological reactivity are also at increased risk for aggression (Lorber, Reference Lorber2004; Scarpa & Raine, Reference Scarpa and Raine1997). Specifically, children who show extreme reactivity to stress or frustration may be more likely to engage in aggression (Hubbard et al., Reference Hubbard, Smithmyer, Ramsden, Parker, Flanagan, Dearing and Simons2002; Moore et al., Reference Moore, Hubbard, Morrow, Barhight, Lines, Sallee and Hyde2018; Scarpa et al., Reference Scarpa, Haden and Tanaka2010), in line with prominent theoretical models of aggression (Berkowitz, Reference Berkowitz1989, Reference Berkowitz1993). More recent research has focused on individual variability in peripheral physiology, specifically variation in phasic respiratory sinus arrhythmia (RSA), as an indicator of physiological reactivity and a risk factor for aggression. RSA refers to the amount of variability between heartbeats (i.e. inter-beat interval) that rhythmically fluctuates with respiration, and this is typically operationalized as high-frequency (HF) heart rate variability (HRV) using power statistics (Berntson et al., Reference Berntson, Thomas Bigger, Eckberg, Grossman, Kaufmann, Malik and Stone1997). This non-invasive index is of particular interest, given its unique association with parasympathetic nervous system (PNS) function, specifically vagal control of the sinoatrial node (Berntson, Cacioppo, & Quigley, Reference Berntson, Cacioppo and Quigley1994), and its implicated role in self-regulation (Beauchaine, Reference Beauchaine2001; Porges, Reference Porges2007). During rest, tonic PNS activation functions via the vagus nerve to slow heart rate and increase its variability (i.e. higher RSA), which is thought to facilitate emotion and behavior regulation. During stress or frustration, withdrawal of PNS control results in increased heart rate and reduced RSA variability, allowing one to mobilize the metabolic resources needed to optimally respond to environmental demands (i.e. RSA reactivity; Porges, Reference Porges2007). Consistent with this theoretical perspective, better emotional and behavioral functioning is generally linked to higher tonic RSA and moderate RSA reactivity (specifically RSA withdrawal) to environmental stress or frustration (Graziano & Derefinko, Reference Graziano and Derefinko2013).
While moderate RSA withdrawal is considered an adaptive and necessary response to stress, excessive withdrawal may be problematic, as it is associated with an extreme mobilization of fight or flight responding (Porges, Reference Porges2007). Although truly dangerous circumstances may require a pronounced physiological reaction to enable necessary behavioral responses, marshaling a pronounced RSA response to everyday frustrations may be less contextually appropriate, and by extension maladaptive. Indeed, excessive RSA reactivity (i.e. greater RSA withdrawal) in response to frustration has been linked to increased risk for aggression (Beauchaine et al., Reference Beauchaine, Bell, Knapton, McDonough-Caplan, Shader and Zisner2019; Byrd et al., Reference Byrd, Vine, Beeney, Scott, Jennings and Stepp2022a; Fanti et al., Reference Fanti, Eisenbarth, Goble, Demetriou, Kyranides, Goodwin and Cortese2019). However, most of the work in this area has focused on samples of older children and adolescents, limiting our understanding of these associations early in development. Studies that have examined this association during the preschool period show mixed results, with some linking risk for aggression to excessive RSA withdrawal (e.g. Beauchaine et al., Reference Beauchaine, Gatzke-Kopp, Neuhaus, Chipman, Reid and Webster-Stratton2013) and others to mild RSA withdrawal or augmentation (e.g. Calkins & Dedmon, Reference Calkins and Dedmon2000). Task differences may be partly responsible for the inconsistent findings (e.g. passive viewing of emotional videos v. engaging in a behavioral frustration task), with some suggestion that more ecologically valid tasks eliciting frustration more reliably produce expected RSA withdrawal (Murray-Close, Holterman, Breslend, & Sullivan, Reference Murray-Close, Holterman, Breslend and Sullivan2017). Additionally, it is possible that mixed results stem from a failure to consider relevant environmental moderators, like maternal invalidation.
The interaction of maternal invalidation and RSA reactivity and risk for aggression
Existing studies of RSA reactivity and child aggression have rarely examined the potentially moderating impact of maternal invalidation despite theoretical reasons for expecting this effect. Diathesis–stress (Zuckerman, Reference Zuckerman and Zuckerman1999) and biosocial (Beauchaine & Zalewski, Reference Beauchaine, Zalewski, Dishion and Snyder2016; Crowell, Beauchaine, & Linehan, Reference Crowell, Beauchaine and Linehan2009; Linehan, Reference Linehan1993) models suggest that sensitivity to environmental stressors will be more strongly linked with emotional and behavioral problems (e.g. aggression) in environments that are emotionally invalidating. For example, children who experience heightened emotional reactivity in response to stress or frustration and experience invalidation of such emotional intensity may have difficultly inhibiting behavioral responses in the context of those emotions, ultimately increasing risk for aggression. Indeed, the interaction between maternal invalidation and physiological reactivity has been associated with emotion and behavior dysregulation (Dixon-Gordon, Marsh, Balda, & McQuade, Reference Dixon-Gordon, Marsh, Balda and McQuade2020; McQuade & Breaux, Reference McQuade and Breaux2017; McQuade, Dixon-Gordon, Breaux, & Babinski, Reference McQuade, Dixon-Gordon, Breaux and Babinski2021). However, we are aware of only one study that examined this interaction in preschoolers, which demonstrated that mild RSA withdrawal or augmentation and maternal rejection predicted increased aggression (Wagner, Hastings, & Rubin, Reference Wagner, Hastings and Rubin2018). This study assessed RSA reactivity to an anger-inducing video and focused on general child-rearing attitudes in a community sample of preschoolers. To better test diathesis–stress and biosocial theories, additional studies are needed that assess RSA reactivity using more externally valid frustration tasks and measure maternal invalidation of negative emotion specifically.
Maternal ER difficulties as a key risk factor
Not surprisingly, children of mothers with ER difficulties (i.e. experiencing emotional responses as more intense, variable, and prolonged) are at heightened risk for aggression (Rutherford et al., Reference Rutherford, Wallace, Laurent and Mayes2015; Zimmer-Gembeck, Rudolph, Kerin, & Bohadana-Brown, Reference Zimmer-Gembeck, Rudolph, Kerin and Bohadana-Brown2021). Research points to child physiological reactivity and maternal invalidation as two risk factors that may help to explain this intergenerational transmission (Rueger, Katz, Risser, & Lovejoy, Reference Rueger, Katz, Risser and Lovejoy2011; Zimmer-Gembeck et al., Reference Zimmer-Gembeck, Rudolph, Kerin and Bohadana-Brown2021). Children of parents with ER difficulties are more likely to have heightened physiological reactivity (Cao, Powers, Cross, Bradley, & Jovanovic, Reference Cao, Powers, Cross, Bradley and Jovanovic2017; Gao, Brown, Neff, Crowell, & Conradt, Reference Gao, Brown, Neff, Crowell and Conradt2021; Ostlund et al., Reference Ostlund, Vlisides-Henry, Crowell, Raby, Terrell, Brown and Shakib2019), placing them at risk for aggression (Lorber, Reference Lorber2004; Scarpa & Raine, Reference Scarpa and Raine1997). Additionally, because mothers with ER difficulties may find it especially difficult to respond in a validating or supportive manner to their child's expression of emotion (Buckholdt et al., Reference Buckholdt, Parra and Jobe-Shields2014; Rutherford et al., Reference Rutherford, Wallace, Laurent and Mayes2015), they may be more likely to dismiss, magnify, or punish their child's emotional experience, even if unintentionally (Morelen, Shaffer, & Suveg, Reference Morelen, Shaffer and Suveg2016; Zimmer-Gembeck et al., Reference Zimmer-Gembeck, Rudolph, Kerin and Bohadana-Brown2021). Examining the independent and interactive effects of child physiological reactivity and maternal invalidation among at-risk preschoolers has the potential to enhance etiological models and aid in the identification of modifiable prevention targets that divert youth away from trajectories of severe psychopathology.
Current study
The current study sought to extend prior work by assessing the independent and interactive effects of child RSA reactivity to an ecologically valid frustration task and maternal invalidation on teacher-reported aggression. Participants were preschool-aged children of mothers with ER difficulties and mothers without ER difficulties. We hypothesized an association between maternal ER difficulties and both child RSA reactivity to frustration and maternal invalidation, and, as outlined in diathesis–stress and biosocial theories (e.g. Crowell et al., Reference Crowell, Beauchaine and Linehan2009; Linehan, Reference Linehan1993; Zuckerman, Reference Zuckerman and Zuckerman1999), that these factors would interact to predict teacher-reported aggression.
Method
Sample
We enrolled 90 mothers (M age = 33.17 years, s.d. = 4.83; 36.7% racial/ethnic minoritized statusFootnote †Footnote 1) and their preschool-aged children (M age = 42.48 months; s.d.= 3.78; 56% female; 46.7% racial/ethnic minoritized statusFootnote 2) in a randomized control trial (RCT) of Dialectical Behavior Therapy (DBT). Mothers were recruited through targeted multimedia and digital messaging programs for mothers of children between 36 and 47 months old (i.e. one advertisement targeting mothers with ER difficulties and one targeting mothers without ER difficulties), via a university-based research recruitment program. Psychiatric treatment clinics were also contacted to aid in the recruitment of mothers with ER difficulties.
At the first point of contact, phone screening interviews were completed to ensure all mothers were a biological parent and had at least 50% physical custody of the target child since birth. To assess for maternal ER difficulties, the 10-item McLean Screening Instrument for Borderline Personality Disorder (MSI-BPD; Zanarini et al., Reference Zanarini, Vujanovic, Parachini, Boulanger, Frankenburg and Hennen2003) was completed by all mothers, where scores ⩾7 were required for mother with ER difficulties and scores ⩽2 were required for mothers without ER difficulties. Given that this was an RCT, mothers with ER difficulties were also asked about current treatment status and those reporting participation in DBT were deemed ineligible. Then, all mothers and their children completed a clinical intake to determine eligibility. This included maternal psychiatric interviews [i.e. Structured Clinical Interview for DSM-5 (SCID-5; First, Williams, Karg, & Spitzer, Reference First, Williams, Karg and Spitzer2015); Structured Interview for DSM-IV Personality (SIDP-IV; Pfohl, Blum, & Zimmerman, Reference Pfohl, Blum and Zimmerman1995)] to determine maternal ER status. Additionally, neuropsychological testing was administered to mothers and children to obtain an estimate of verbal IQ [i.e. Peabody Picture Vocabulary Test Fourth Edition (Dunn & Dunn, Reference Dunn and Dunn2003); Expressive Vocabulary Test Second Edition (Williams, Reference Williams1997)]. All eligible participants demonstrated standard scores of at least 70. Mothers also completed a brief child development screening, the Ages and Stages Questionnaire (ASQ; Squires, Bricker, & Twombly, Reference Squires, Bricker and Twombly2009), designed to detect delays in development across developmental domains, and only children without delays were eligible.
Procedure
Following the clinical intake, all eligible mothers and their preschoolers were asked to complete four study assessments (baseline, 4-, 8-, and 12-month follow-ups). These assessments included questionnaires assessing emotions and behaviors as well as mother–child interactions (e.g. maternal invalidation). Participants were also asked to complete a series of behavioral tasks, including a child frustration task, during which RSA was continuously recorded. Mothers were also asked to provide contact information for their child's preschool teacher or daycare provider. Following the assessment, teachers were contacted and asked to complete an online questionnaire assessing emotions and behaviors observed in the preschool/daycare setting. The current study focuses on 77 mother–child dyads recruited between October 2017 and January 2020 who completed an in-person baseline assessment.Footnote 3
Measures
Maternal ER difficulties
Maternal ER status (0 = no ER difficulties; 1 = ER difficulties) was determined during the clinical intake, which included semi-structured diagnostic interviews (i.e. SCID-5, SIDP-IV) administered by trained research personnel. Mothers with ER difficulties met at least three diagnostic criteria for borderline personality disorder, a disorder hallmarked by ER difficulties (Lieb, Zanarini, Schmahl, Linehan, & Bohus, Reference Lieb, Zanarini, Schmahl, Linehan and Bohus2004; Linehan, Reference Linehan1993), with one of these three symptoms being affective instability or uncontrolled anger. Mothers with no ER difficulties did not meet diagnostic criteria for any clinical disorder (e.g. depression, anxiety), currently or since conception of their child. Additionally, these mothers showed no evidence of affective instability and uncontrolled anger criteria (i.e. a severity score of 0). Double-coding of approximately 20% of clinical interviews showed strong inter-rater reliability for maternal ER difficulties (Krippendorff's α = 0.91) and Table S1 details the prevalence of DSM-5 diagnoses in the current sample.
Maternal invalidation
Maternal invalidation was assessed using the Coping with Children's Negative Emotions Scale (CCNES; Fabes, Poulin, Eisenberg, & Madden-Derdich, Reference Fabes, Poulin, Eisenberg and Madden-Derdich2002). The CCNES is a self-report measure consisting of six, 12-item subscales designed to assess parental response to their child's negative emotions, with three subscales reflecting unsupportive reactions (i.e. minimizing reactions, distress reactions, and punitive reactions). Mothers read several different hypothetical scenarios during which the child feels a negative emotion and following each scenario they rated the likelihood of their responding a certain way on a seven-point Likert-type scale ranging from 1 (very unlikely) to 7 (very likely). The average of all items from the three unsupportive subscales represented maternal invalidation (range = 1–7). Reliability for this scale was good (α = 0.88), and consistent with reliability estimates in similar samples (Meyer, Raikes, Virmani, Waters, & Thompson, Reference Meyer, Raikes, Virmani, Waters and Thompson2014; Perry, Calkins, Nelson, Leerkes, & Marcovitch, Reference Perry, Calkins, Nelson, Leerkes and Marcovitch2012).
Child physiological reactivity to frustration
Child RSA was assessed continuously as an index of parasympathetic function during a 3-minute resting baseline (i.e. watching a Mr. Rogers video) and a 2-minute frustration task. RSA reactivity to frustration was measured using two well-validated frustration tasks: Transparent Locked Box (LAB-TAB; Goldsmith & Rothbart, Reference Goldsmith and Rothbart1996) and Knotted Sack (Chaplin, Klein, Cole, & Turpyn, Reference Chaplin, Klein, Cole and Turpyn2017).Footnote 4 In each task, the child was allowed to pick their favorite of three toys. The experimenter then placed the chosen toy inside a locked, transparent box or an opaque cloth sack and told the child they could keep the toy once they opened the locked box or knotted sack. Unbeknownst to the children, those in the box condition were then handed an incorrect set of keys, and those in the sack condition were handed an alternate sack that was glued shut. The experimenter explained that they ‘had some work to do’ and turned away from the child as if engrossed in work. The child attempted to open the locked box or knotted sack for 2 minutes.
Electrocardiogram signals were obtained from three disposable Ag/Ag-Cl spot electrodes positioned in a modified lead-II configuration using Mindware BioLab software (MindWare Technologies, Ltd., Gahanna, OH, USA). To estimate RSA, Mindware HRV 3.2.6 software (MindWare) was utilized. The interbeat interval (IBI) series was resampled in equal 250 ms intervals, linearly detrended, and tapered using a Hanning window. Trained scorers independently visually inspected each recorded waveform and manually corrected artifacts based on recommendations set forth by Berntson et al. (Reference Berntson, Thomas Bigger, Eckberg, Grossman, Kaufmann, Malik and Stone1997). Twenty percent of participants were double-scored for reliability (mean Krippendorff's α = 0.89), and any discrepancies were resolved with consensus. HRV was calculated using fast Fourier transformation analysis of the IBI series, and RSA was defined as HRV associated with the log transformed HF respiratory power band (0.24–1.04 Hz range; Shader et al., Reference Shader, Gatzke-Kopp, Crowell, Reid, Thayer, Vasey and Beauchaine2018; West, Shaffer, Wickrama, Han, & Suveg, Reference West, Shaffer, Wickrama, Han and Suveg2021). Data were available for 95% (n = 73) of the sample,Footnote 5 and peak respiration frequency ranged from 0.26 to 0.84. RSA was estimated separately for the resting baseline (mean = 6.02; s.d. = 1.38) and for the frustration task (mean = 5.40; s.d. = 1.18). To measure within-individual RSA reactivity, a difference score was calculated by subtracting RSA during the resting baseline from RSA during the frustration task. Thus, negative scores reflect RSA withdrawal (reduced RSA during frustration relative to baseline), while positive scores reflect RSA augmentation (increased RSA during conflict relative to baseline). In this sample, mean RSA reactivity was negative (mean = −0.62; s.d. = 0.67; range = − 2.58–0.64), with approximately 85% of preschoolers experiencing RSA withdrawal, and approximately 15% experiencing mild RSA augmentation.
Child aggression
To assess aggression, preschool teachers or daycare providers completed the Caregiver-Teacher Report Form (C-TRF; Achenbach & Rescorla, Reference Achenbach and Rescorla2001) via the Qualtrics survey system (Qualtrics, Provo, UT). The C-TRF contains 25 items assessing aggression in children who are between 1.5 and 5 years old (e.g. defiant, physically attacks people, screams a lot). All items are rated on a three-point Likert scale, ranging from 0 (not true) to 2 (very true or often true), and are summed to create a total score. Data were available for 83% of the sample (n = 64),Footnote 6 and reliability for this scale was excellent (α = 0.95).
Demographic covariates
Child age, racial/ethnic minoritized status (0 = white; 1 = minoritized status), and child sex (0 = male; 1 = female) were obtained via maternal report. Annual income and family receipt of public assistance were obtained via maternal report (e.g., food stamps, welfare, etc.; 0 = no public assistance; 1 = receipt of public assistance).
Data analytic strategy
Preliminary analyses were conducted to examine descriptive statistics and bivariate correlations between study variables using IBM SPSS Statistics (Version 26.0). Primary analyses were conducted in MPlus version 8 (Muthén & Muthén, Reference Muthén and Muthén2017) using full information maximum likelihood with robust standard errors to handle missing data. The independent and interactive effects of maternal invalidation and child RSA reactivity on teacher-reported aggression were estimated simultaneously while controlling for theoretically relevant demographic covariates (i.e. child age, child sex, child minoritized status, family receipt of public assistance), and child baseline RSA. The effects of maternal ER difficulties on maternal invalidation, child RSA reactivity, and teacher-reported aggression were also included in the model. Model fit was evaluated using standard criteria for χ2, comparative fit index (CFI; Bentler, Reference Bentler1990), and the root mean square error of approximation (RMSEA; Browne & Cudeck, Reference Browne, Cudeck, Bollen and Long1993). For CFI, conventional cut-off values of 0.95 or greater indicate good fit (McDonald & Ho, Reference McDonald and Ho2002). RMSEA values below 0.05 represent good fit (Kline, Reference Kline2015; McDonald & Ho, Reference McDonald and Ho2002). Standardized effects from the full model are reported. Significant interaction effects were probed and plotted for interpretation using maternal invalidation values ± 1 s.d. above and below the mean. Fraley's (Reference Fraley2018) online utility for parsing the two-way interactions was used to assess simple slopes and regions of significance.
Results
Descriptive statistics
Table 1 includes descriptive statistics for demographic and primary study variables and Table 2 shows bivariate correlations. Maternal ER difficulties were associated with higher maternal invalidation, more excessive child RSA withdrawal to frustration, and greater teacher-reported aggression. Maternal invalidation was positively associated with teacher-reported aggression. Child RSA reactivity was negatively associated with teacher-reported aggression, though not significantly.
Note. ER, emotion regulation; M, mean; RSA, respiratory sinus arrythmia; s.d., standard deviation. Means designated with different subscript letters are significantly different from each other (p < 0.05) based on post-hoc independent sample t tests.
Note. Significant effects are bolded. *p < 0.05; **p < 0.01
Independent and interactive associations with aggression
Figure 1 shows the multivariate model testing the independent and interactive effects of maternal invalidation and child RSA reactivity to frustration on teacher-reported aggression. Maternal ER difficulties were associated with higher levels of maternal invalidation and more excessive RSA withdrawal to frustration. Additionally, the interaction between maternal invalidation and child RSA reactivity was significantly associated with teacher-reported aggression. Post-hoc simple slope analyses showed that RSA reactivity to frustration was related to teacher-reported aggression at high levels of maternal invalidation (+1 s.d.), but not low levels of maternal invalidation (−1 s.d.). Region of significance analyses indicated that higher maternal invalidation was significantly associated with more teacher-reported aggression among children with more extreme RSA withdrawal (Fig. 2).Footnote 7
Discussion
The current study examined the independent and interactive effects of maternal invalidation and child RSA reactivity to frustration as predictors of teacher-reported aggression in an at-risk sample of preschoolers. As expected, results demonstrated positive associations between clinician-rated maternal ER difficulties and both maternal invalidation and child RSA reactivity to frustration. As hypothesized, there was a significant interaction between maternal invalidation and child RSA reactivity, such that higher levels of maternal invalidation predicted more aggression in a preschool/daycare setting among children who experienced more excessive RSA withdrawal to frustration. Importantly, this effect was demonstrated while simultaneously accounting for the effects of demographic covariates and child baseline RSA. Findings are in line with diathesis–stress and biosocial models of risk and point to multiple targets for prevention and early intervention.
Mothers with ER difficulties reported higher maternal invalidation, and their children had more excessive RSA withdrawal to frustration, echoing previous research demonstrating associations between maternal ER difficulties and maternal invalidation of emotion and child physiological reactivity (Cao et al., Reference Cao, Powers, Cross, Bradley and Jovanovic2017; Frigoletto et al., Reference Frigoletto, Byrd, Vine, Vanwoerden, Zalewski and Stepp2022; Gao et al., Reference Gao, Brown, Neff, Crowell and Conradt2021; Ostlund et al., Reference Ostlund, Vlisides-Henry, Crowell, Raby, Terrell, Brown and Shakib2019; Zimmer-Gembeck et al., Reference Zimmer-Gembeck, Rudolph, Kerin and Bohadana-Brown2021). Mothers with ER difficulties may feel overwhelmed by their own internal emotional experience when attempting to navigate challenging emotional interactions with their child, making it more difficult to respond effectively (Rutherford et al., Reference Rutherford, Wallace, Laurent and Mayes2015). These interactions can be emotionally evocative for any parent, and given that children of mothers with ER difficulties may also have greater physiological reactivity to frustration (Cao et al., Reference Cao, Powers, Cross, Bradley and Jovanovic2017; Gao et al., Reference Gao, Brown, Neff, Crowell and Conradt2021; Ostlund et al., Reference Ostlund, Vlisides-Henry, Crowell, Raby, Terrell, Brown and Shakib2019), future work should examine whether this is even more challenging for mothers with ER difficulties. Because preschoolers still primarily rely on external influences to aid in regulation (Thompson, Reference Thompson1994), modifying maternal responses to child emotion during this time has the potential to significantly shape child outcomes. Taken together, these findings highlight the importance of characterizing these influences during the preschool period, a sensitive developmental window marked by notable shifts in emotional and behavioral regulation (Brown & Jernigan, Reference Brown and Jernigan2012; Garon et al., Reference Garon, Bryson and Smith2008).
Our results demonstrated a significant interaction between maternal invalidation and child RSA reactivity. Specifically, children who experienced RSA withdrawal to frustration and higher maternal invalidation showed more aggression in the preschool or daycare setting. This finding suggests that the impact of maternal invalidation may not be equivalent across all children and demonstrates that the most deleterious effects may be felt by those children with heightened physiological reactivity, in line with the diathesis–stress and biosocial models (e.g. Crowell et al., Reference Crowell, Beauchaine and Linehan2009; Linehan, Reference Linehan1993; Zuckerman, Reference Zuckerman and Zuckerman1999). Together, these factors placed children at higher risk for aggression during preschool, a developmental window typically characterized by a normative decline in aggression (Hartup, Reference Hartup1974; Tremblay et al., Reference Tremblay, Nagin, Seguin, Zoccolillo, Zelazo, Boivin and Japel2005), increasing their risk for a wide range of psychopathology later in development (Loeber & Hay, Reference Loeber and Hay1997; Ostrov & Houston, Reference Ostrov and Houston2008; Schaeffer et al., Reference Schaeffer, Petras, Ialongo, Poduska and Kellam2003). For children with heightened physiological reactivity, emotional scaffolding and validation may be even more important, as invalidation in the context of heightened physiological reactivity may limit crucial opportunities for youth to learn how to regulate their emotions, and over time, exacerbate emotional distress, increasing risk for aggression. Along these lines, recent meta-analytic work shows that physiological reactivity, and specifically RSA withdrawal, decreases during the first 3 years of life (Wagner, Holochwost, Lynch, Mills-Koonce, & Propper, Reference Wagner, Holochwost, Lynch, Mills-Koonce and Propper2021), with some suggestion that maternal scaffolding and validation may directly support this trajectory (Perry, Dollar, Calkins, & Bell, Reference Perry, Dollar, Calkins and Bell2018). Taken together, these findings underscore the sensitivity of this developmental window, when prevention and intervention efforts may be critical and potentially most effective.
Limitations
Findings from the current study should be considered within the context of several limitations. First, this study focused on an at-risk sample of preschoolers at a single timepoint, limiting the generalizability of findings to community samples and our ability to assess effects over time. Second, while several important covariates (e.g. age, sex, minoritized status) were included in our model, this study was not adequately powered to examine potential moderation. Moreover, minoritized status was dichotomized and utilized in statistical models as a person-centered variable. Race is a non-discrete, socially created construct and reflects the effects of numerous risk factors (e.g., minority stress) for which minoritized status is a proxy (Kaufman & Cooper, Reference Kaufman and Cooper2001; Richeson & Sommers, Reference Richeson and Sommers2016). Future work is needed to examine the direct impact of these factors on maternal ER difficulties, maternal invalidation, and aggression (Jones & Neblett, Reference Jones and Neblett2017). Additionally, while we assessed invalidation using a well-validated maternal-reported questionnaire (i.e. CCNES), research highlights children's perception or experience of validation as most predictive (e.g. Byrd et al., Reference Byrd, Vine, Frigoletto, Vanwoerden and Stepp2022b), and future work should utilize alternative assessment methods and informants. Finally, while our assessment of peripheral physiology expands on previous laboratory-based assessments (i.e. passive viewing of emotional stimuli) by utilizing a more ecologically valid frustration task, we acknowledge the importance of assessing task-induced artifacts and the benefits of utilizing standardized methods across studies (Davis, Brooker, & Kahle, Reference Davis, Brooker and Kahle2020). Additionally, although we focused on RSA as an indicator of parasympathetic function and used difference scores to assess reactivity, we understand that other autonomic influences are likely at play (i.e. impedance cardiography) and recognize the importance of modeling dynamic changes in physiology over time (Hastings & Kahle, Reference Hastings, Kahle, LoBue, Pérez-Edgar and Buss2019).
Clinical implications
The current study points to the downstream effects of maternal ER difficulties early in development and suggests that maternal invalidation and child physiological reactivity interact to increase risk for aggression, particularly among at-risk youth. Findings highlight the significance of integrating these factors into etiological models of aggression and underscore potential treatment implications. For example, research demonstrates that targeting maternal ER improves parenting behaviors (Martin, Roos, Zalewski, & Cummins, Reference Martin, Roos, Zalewski and Cummins2017; Zalewski, Lewis, & Martin, Reference Zalewski, Lewis and Martin2018), and our own preliminary work in this sample has demonstrated that treatment-driven improvements in maternal ER difficulties has indirect effects on child externalizing symptoms 1 year later (Byrd, Lee, Frigoletto, Zalewski, & Stepp, Reference Byrd, Lee, Frigoletto, Zalewski and Stepp2021). Moreover, emerging work suggests that targeting maternal ER in combination with maternal validation training may further enhance child outcomes (Havighurst & Kehoe, Reference Havighurst, Kehoe, Deater-Deckard and Panneton2017; Highlander et al., Reference Highlander, Zachary, Jenkins, Loiselle, McCall, Youngstrom and Jones2022), and our data suggest that maternal validation training for mothers with ER difficulties may be especially indicated when their children show heightened physiological reactivity to frustration. Moreover, given the extent to which intense negative emotion and aggression are intricately intertwined, strategies that help parents to separate the valid emotional experience from the maladaptive aggressive response may be useful. Alternatively, directly targeting children's physiological reactivity to frustration (e.g. eliciting the dive reflex to activate the PNS; Rathus & Miller, Reference Rathus and Miller2000) may be especially effective in the context of maternal invalidation. Taken together, these findings suggest that targeted prevention and intervention efforts, prior to the emergence of severe psychopathology, may have the potential to shift trajectories of at-risk children.
Supplementary material
The supplementary material for this article can be found at https://doi.org/10.1017/S0033291722003713
Acknowledgements
We are grateful to all the families who took part in this study, and to the research study team, which includes interviewers and their supervisors, study therapists, research assistants, data managers, student workers, and volunteers. Funding for this study was supported by grants awarded to Dr Maureen Zalewski and Dr Stephanie Stepp from the National Institute of Mental Health (R01 MH111758). Additional funding from the National Institute of Mental Health also supported this work (K01 MH119216; F32 MH126510).
Conflict of interest
None.