Large-scale data decipher children's scale errors: A meta-analytic approach using the zero-inflated Poisson models.

Scale errors are intriguing phenomena in which a child tries to perform an object-specific action on a tiny object. Several viewpoints explaining the developmental mechanisms underlying scale errors exist; however, there is no unified account of how different factors interact and affect scale errors, and the statistical approaches used in the previous research do not adequately capture the structure of the data. By conducting a secondary analysis of aggregated datasets across nine different studies (n = 528) and using more appropriate statistical methods, this study provides a more accurate description of the development of scale errors. We implemented the zero-inflated Poisson (ZIP) regression that could directly handle the count data with a stack of zero observations and regarded developmental indices as continuous variables. The results suggested that the developmental trend of scale errors was well documented by an inverted U-shaped curve rather than a simple linear function, although nonlinearity captured different aspects of the scale errors between the laboratory and classroom data. We also found that repeated experiences with scale error tasks reduced the number of scale errors, whereas girls made more scale errors than boys. Furthermore, a model comparison approach revealed that predicate vocabulary size (e.g., adjectives or verbs), predicted developmental changes in scale errors better than noun vocabulary size, particularly in terms of the presence or absence of scale errors. The application of the ZIP model enables researchers to discern how different factors affect scale error production, thereby providing new insights into demystifying the mechanisms underlying these phenomena. A video abstract of this article can be viewed at https://youtu.be/1v1U6CjDZ1Q RESEARCH HIGHLIGHTS: We fit a large dataset by aggregating the existing scale error data to the zero-inflated Poisson (ZIP) model. Scale errors peaked along the different developmental indices, but the underlying statistical structure differed between the in-lab and classroom datasets. Repeated experiences with scale error tasks and the children's gender affected the number of scale errors produced per session. Predicate vocabulary size (e.g., adjectives or verbs) better predicts developmental changes in scale errors than noun vocabulary size.

The successful use of a search strategy improves with visuospatial working memory in 2- to 4.5-year-olds.

Using spatial cues such as shape, orientation, and pattern aids visuospatial working memory because it allows strategies that reduce the load on this cognitive resource. One such strategy, namely taking advantage of patterned spatial distributions, remains understudied to date. This strategy demands keeping track of already-searched locations and excluding them from further search and so correlates with visuospatial working memory. The use of such strategies should, in principle, develop in early childhood, but because most studies focus on chunking, the development of other strategies reducing the load on working memory is understudied in young children. Therefore, in this study we tested whether children aged 2 to 4.5 years (N = 97) could take advantage of spatial cues in their search and whether this ability correlated with their age, verbal ability, and visuospatial working memory. The results showed that the ability to use a patterned spatial distribution (searching a row of locations from one side to the other instead of a random search) significantly improved with visuospatial working memory but not with age or verbal ability. These results suggest that visuospatial abilities may rapidly develop from 2 to 4.5 years of age, and given their impact on later mathematic achievement, demand increased attention in cognitive developmental research and early childhood education.

Continuity in false belief understanding from 33 to 52 months of age.

Conceptual continuity in children's false belief understanding from toddlerhood to childhood was investigated in a longitudinal study of 75 children. Performance in a low-demands false belief task at 33 months of age was significantly correlated with performance in a content false belief task at 52 months independent of language ability and executive function. In contrast, there was no correlation with performance in a location false belief task, which differed from the "Sally-Anne" format of the low-demands task and was high in executive demands. These findings support the view that explicit false belief understanding may be continuous from toddlerhood to childhood and that developmental change may be characterized in terms of enrichment and increasing stability of core conceptual understanding rather than in terms of fundamental change.

Provoked and unprovoked aggression in toddlerhood: Evaluating measurement invariance and latent means across gender, age, and time.

This paper re-examined the factor structure of a recently developed parent report of aggression, the Provoked and Unprovoked Aggression Questionnaire, and evaluated measurement invariance and latent mean differences across gender, age, and time. Participants were 333 mothers of toddlers (younger age group: n = 167, 53.9% boys, Mage Time 1 = 18.30 months, SD = 0.45; older age group: n = 166, 48.8% boys, Mage Time 1 = 24.29 months, SD = 0.38) who filled out provoked (eight items) and unprovoked (five items) aggression scales twice over a 3-month period. We found evidence for the configural, metric, and scalar measurement invariance-a requirement needed to make a meaningful comparison between aggression means across gender, age groups, and time. When comparing means for boys and girls, gender differences emerged earlier for unprovoked than provoked aggression. Also, the frequency of provoked aggression increased among younger, but not older, toddlers. By developing a brief parental report of aggression in toddlerhood, we hope to fill a void of early aggression measures that tap the contextual variability in aggressive behaviors, and thereby stimulate more research to further our understanding of different types of aggression and their correlates in toddlerhood.

Internal state language factor structure and development in toddlerhood: Insights from WordBank.

Internal state language (ISL) research contains knowledge gaps, including dimensionality and predictors of growth, addressed here in a two-aim study. Parent-reported expressive language from N = 6,373 monolingual, English-speaking toddlers (Mage = 23.5mos, 46% male, 57% white) was collected using cross-sectional and longitudinal data in WordBank. Exploratory and confirmatory factor analyses suggested a best-fitting one-factor model of ISL. The single-factor model of ISL was then submitted to hierarchical linear modeling to evaluate predictors of ISL development. Age 2 ISL production was predicted by child sex, wherein females outperform males, and maternal education, wherein higher education contributes to higher ISL. Only maternal education emerged as a significant predictor of ISL growth. These results provide support to theory suggesting a unitary construct of ISL, as opposed to considering ISL as categorical, and further illustrate linear growth through the second postnatal year that varies as a function of child sex and maternal education.

Cortisol and testosterone concentrations during the prenatal and postpartum period forecast later caregiving quality in mothers and fathers.

Given that parental caregiving quality affects child development from birth onwards, it is important to detect parents who are at risk for low-quality caregiving as early as possible, preferably before or soon after birth. This study investigated whether cortisol (CORT) and testosterone (T) measured during the last trimester of pregnancy and six weeks postpartum were associated with observed caregiving quality at child age 3 in mothers (N = 63) and fathers (N = 45). CORT and T were measured during an interaction with a simulator infant (pregnancy) and their own infant (postpartum). In mothers, no associations were found with CORT and T during pregnancy, but higher postpartum CORT during a mother-infant interaction was related to higher caregiving quality during toddlerhood. In fathers, the association between T during pregnancy and caregiving quality in toddlerhood was more negative for fathers with low CORT. In contrast to mothers, higher postpartum CORT in fathers was associated with lower caregiving quality in toddlerhood. These findings proved robust after applying the Benjamini-Hochberg procedure to control for false discovery rate. Our findings indicate that CORT and T during the perinatal period can forecast caregiving quality in both mothers and fathers. Moreover, our results provided evidence for the dual-hormone hypothesis, but only in fathers. These findings contribute to our growing understanding on how endocrine measures explain individual differences in caregiving quality in mothers and fathers.

A mixed methods study of siblings' roles in maternal feeding practices in early childhood: an application of the learning from experience process.

BACKGROUND: Firstborn children have higher rates of obesity compared to secondborns, perhaps due, in part, to differential feeding practices. Despite the centrality of siblings in family life and potential for influence, almost nothing is known about the role of siblings in parent feeding practices in early childhood. METHODS: Participants (n = 117) were mothers of consecutively born siblings. Firstborns participated in an RCT that compared a responsive parenting intervention designed for primary prevention of obesity against a safety control. Secondborns participated in an observational cohort. Multilevel models tested whether and how firstborn characteristics (temperament, appetite, rapid weight gain) at 16 weeks and 1 year were associated maternal feeding practices of secondborns in infancy at 16 weeks, 28 weeks, and 1 year (food to soothe) and at ages 1, 2, and 3 years (structure-and control-based feeding practices). A purposive subsample (n = 30) of mothers also participated in semi-structured interviews to further illuminate potential sibling influences on maternal feeding practices during infancy and toddlerhood. RESULTS: Firstborn characteristics did not predict secondborn feeding in infancy (all ps > 0.05). Firstborn negative affect, however, predicted mothers' less consistent mealtime routines (b (SE) = - 0.27 (0.09); p = 0.005) and more pressure (b (SE) = 0.38 (0.12); p = 0.001). Firstborn appetite predicted mothers' less frequent use of food to soothe (b (SE) = - 0.16 (0.07); p = 0.02) when secondborns were toddlers. Firstborn surgency, regulation, and rapid weight gain, however, did not predict secondborn feeding practices during toddlerhood (all ps > 0.05). Interviews with mothers revealed three ways that maternal experiences with firstborns informed feeding practices of secondborns: 1) Use of feeding practices with secondborn that worked for the firstborn; 2) Confidence came from firstborn feeding experiences making secondborn feeding less anxiety-provoking; and 3) Additional experiences with firstborn and other factors that contributed to secondborn feeding practices. CONCLUSIONS: Some firstborn characteristics and maternal experiences with firstborns as well as maternal psychosocial factors may have implications for mothers' feeding practices with secondborns. Together, these mixed methods findings may inform future research and family-based interventions focused on maternal feeding of siblings in early childhood.

Mothers' and fathers' executive function both predict emergent executive function in toddlerhood.

There are multivariate influences on the development of children's executive function throughout the lifespan and substantial individual differences can be seen as early as when children are 1 and 2 years of age. These individual differences are moderately stable throughout early childhood, but more research is needed to better understand their origins. To some degree, individual differences in executive function are correlated between mother and child, but no research to date has examined these associations prior to when children are preschool age, nor have any studies considered the role of fathers' and mothers' executive function in tandem. Here, we use a sample of 484 families (Mothers 89.2% white; Fathers 92.5% white) in three countries (UK, USA, Netherlands) to investigate the role of each parents' executive function on the development of children's (49.7% female) executive function from 14 (M = 14.42, SD = 0.57) to 24 (M = 24.47, SD = 0.78) months, as well as parenting practices that underlie these associations. Results of structural equation models suggest stability in some-but not all-components of executive function and growing unity between components as children age. We replicate extant findings such that mothers' executive function predicts children's executive function over and above stability and extend these findings to include associations between father and child skills. We find an additive role of fathers' EF, similar in magnitude to the role of mothers' EF. Finally, for both mothers and fathers we find that sensitivity and autonomy supportive practices mediate the relations between parents' and children's executive function.

Object labeling activates young children's scale errors at an early stage of verb vocabulary growth.

Scale errors are intriguing developmental phenomena in which young children attempt to perform impossible object-specific actions toward miniature-sized objects. Of several related cognitive abilities, lexical development during toddlerhood enhances scale error production by making objects' semantic representations dominant over perceptual information. To directly address the effect of activated semantic representations on scale errors, we examined whether and when object labeling affected scale errors. Toddlers aged 18 to 30 months (N = 72) performed a body-based scale error task twice: in one session with specific object labels provided (e.g., "chair") and in the other session with general pronouns provided (e.g., "this"). Using different developmental indices, including chronological age and productive vocabulary size of nouns, verbs, and adjectives, the enhancement effect of object labeling was detected only for children whose verb vocabulary size was classified into the medium group (3-26 words). Moreover, verb vocabulary size was determined to be the best predictor of scale error production among the candidate developmental indices. We also found that toddlers produced more scale errors in the first session that they performed the task compared with the second session. In addition to revealing that careful control of relevant factors (e.g., developmental indices, labeling, task repetition) is required for scale error research, this study sheds light on the relevance of verb vocabulary on scale errors.

Parents' expressed emotions and children's executive functions.

The ways in which people talk about their family members may say as much as the words themselves. For example, emotions expressed by family members of mentally ill patients during unscripted speech samples relate to the risk of relapse and the prognosis of psychiatric disorders; however, the idea of expressed emotions as a construct has previously been limited to parents of children and adolescents aged 4-18 years who suffer from severe emotional or behavior dysregulation. Here, we applied an expressed emotions coding paradigm to speech samples obtained from mothers and fathers of 104 typically developing children when the children were 14 months of age. This is the first study applying the expressed emotions coding paradigm at this age. Parents were prompted to give thoughts, attitudes, and feelings about their children; speech samples were coded for critical comments (e.g., "She is very whiny"), emotional over-involvement (e.g., "I was so worried, I couldn't sleep"), and quality of relationship (e.g., "We get along great"). During the same home visit, children completed three executive function tasks that measured children's inhibition, working memory, and cognitive flexibility. We found negative associations between fathers' criticism and their children's inhibition and between fathers' emotional over-involvement and their children's working memory. In contrast, we found positive associations between mothers' expressed quality of relationship and their children's working memory. This approach to analyzing parents' speech samples may allow for unique insights into the thoughts, attitudes, and feelings of new parents and how that might guide children's development.

Associations between maternal eating behaviors and feeding practices in toddlerhood.

Few studies have examined the associations between parents' own eating behaviors and their feeding practices. We aimed to study the associations between maternal eating behaviors and feeding practices in toddlerhood. In this cross-sectional analysis, maternal eating behaviors and feeding practices were assessed at 2-year follow-up by using the Three-Factor Eating Questionnaire (TFEQ-R21) and the Comprehensive Feeding Practices Questionnaire (CFPQ), respectively, among mothers of 1322 children from the EDEN mother-child cohort. Depending on their distributions, scores from the two questionnaires were considered continuous or binary variables, according to the median. Linear or logistic regression models were used as appropriate to assess the associations between maternal eating behaviors, considered simultaneously in a combined model, and their feeding practices. Maternal cognitive restraint was positively associated with maternal restriction for health and restriction for weight. Maternal uncontrolled eating was positively associated with pressure to eat and use of food to regulate the child's emotions. Maternal uncontrolled eating was also negatively associated with restriction for weight, but only among boys. This study supports that mothers' own eating behaviors are associated with their feeding practices in toddlerhood. Further studies are needed to understand the role of parental feeding practices in the familial transmission of eating behavior.

Expressive language in infancy and toddlerhood: The roles of child temperament and maternal parenting behaviors.

Prompt, appropriate, and contingent maternal behaviors play a role in early language acquisition, as do individual differences in children's temperament. However, little work has investigated the combined influence of maternal psychosocial and child biological factors on expressive language development. The purpose of this study was to evaluate the concurrent and longitudinal contributions of responsive/intrusive parenting and child temperament to multiple expressive language outcomes at 10 and 24 months of age. Participants included 407 mothers and children (209 girls). Mothers completed questionnaires about their infant's temperament and language, and maternal parenting was coded during mother-child interaction tasks. Dependent variables included (1) gestures at 10 months, (2) vocabulary at 24 months, (3) mean length of utterance at 24 months, and (4) sentence complexity at 24 months. After controlling for child sex and maternal education, child temperament was associated with language outcomes at 10 and 24 months, whereas intrusive, but not responsive, parenting related to only 24 month language outcomes. Longitudinally, infant negative affectivity predicted sentence complexity in toddlerhood. These findings elucidate the presence of both psychological and biological predictors as they differentially influence various aspects of expressive language development across the first two postnatal years.

Dimensions of the language environment in infancy and symptoms of psychopathology in toddlerhood.

The quality of the early environment influences the development of psychopathology. Children who are deprived of sufficient environmental enrichment in infancy may be at higher risk for developing symptoms of psychopathology in toddlerhood. In this study, we investigated the prospective association between naturalistic measures of adult language input obtained through passive monitoring of infants' daily environments and emerging psychopathology in toddlerhood. In a sample of 100 mothers and their infants recruited from the community (mean age [range] = 6.73 [5-9] months), we used the Language ENvironment Analysis (LENA) system to measure multiple dimensions of infants' language environments, including both the quantity and consistency of adult speech and conversational turns in infants' daily lives as well as the quantity of infant vocalizations. Subsequently, during toddlerhood (mean age [range] = 18.29 [17-21] months), mothers reported on their children's symptoms of psychopathology. Infants who experienced more consistent adult speech and conversational turns had lower symptoms of psychopathology in toddlerhood, independent of negative emotionality in infancy, maternal depressive symptoms, and laboratory-based measures of maternal sensitivity. These findings have implications for the measurement of environmental factors that may confer risk and resilience to emerging psychopathology.

Promoting prosocial behavior in toddlerhood: A conversation-based intervention at nursery.

The awareness that prosocial skills begin to develop during the early years, with lasting implications for social lives, underpins increasing efforts to find ways of promoting prosocial behavior in children. Nevertheless, few such intervention studies have been conducted with toddlers in educational settings. Following the line of inquiry that examines the role of conversation about inner states in the early development of socioemotional competence, the current study makes an original contribution by evaluating the efficacy of a conversational intervention (TEPP, Toddlers Empathy Prosociality Program) in fostering prosocial conduct in young children. A total of 142 toddlers (Mage = 29.78 months, range = 22-36) participated in a 2-month program during which specially trained teachers read prosocial stories to small groups of children and then involved the children in conversations about inner states and prosocial behavior (Condition 1), in conversations about concrete actions and physical states (Condition 2), or in free play activities (Condition 3). Children in Condition 1 were found to outperform their peers in Conditions 2 and 3 on both direct and indirect measures of prosocial behavior. Gender had a further slight influence on the study outcomes. Overall, the results confirmed that intervention based on conversation about inner states and prosocial actions can enhance the development of prosocial skills in toddlers, encouraging the implementation of early education programs targeting prosociality among peers.

Trajectories of internalizing symptoms in early childhood: Associations with maternal internalizing symptoms and child physiology.

Research has shown that children's internalizing symptom development during early childhood are shaped by biopsychosocial processes including physiology and parental symptoms. However, associations between maternal internalizing symptoms, child physiology and trajectories of child internalizing symptoms are not well understood. We used growth curve models to examine how maternal internalizing symptoms, child physiology and the interaction between maternal internalizing symptoms and child physiology may be associated with trajectories of internalizing symptoms during early childhood. Mothers reported their children's internalizing symptoms when children were 3, 4, 5 and 6 years of age, and mothers self-reported their own internalizing symptoms when children were 3. Respiratory Sinus Arrhythmia (RSA) was collected when children were 3.5-years-old. Results showed that there is a non-linear, quadratic trajectory across all participants from age 3 to 6. Maternal internalizing symptoms were not associated with children's internalizing symptoms at age 6, but were associated with both linear and quadratic change. Lower resting RSA was associated with greater increases in children's internalizing symptoms over time. Interactions between maternal internalizing symptoms and RSA were not associated with children's internalizing symptom development. The findings demonstrate that maternal internalizing symptoms and child physiology are independently associated with internalizing symptom development during early childhood.

Observing third-party ostracism enhances facial mimicry in 30-month-olds.

Mimicry is suggested to be one of the strategies via which we enhance social affiliation. Although recent studies have shown that, like adults, young children selectively mimic the facial actions of in-group over out-group members, it is unknown whether this early mimicry behavior is driven by affiliative motivations. Here we investigated the functional role of facial mimicry in early childhood by testing whether observing third-party ostracism, which has previously been shown to enhance children's affiliative behaviors, enhances facial mimicry in 30-month-olds. Toddlers were presented with videos in which one shape was ostracized by other shapes or with control videos that did not show any ostracism. Before and after this, the toddlers observed videos of models performing facial actions (e.g., eyebrow raising, mouth opening) while we measured activation over their corresponding facial muscles using electromyography (EMG) to obtain an index of facial mimicry. We also coded the videos of the sessions for overt imitation. We found that toddlers in the ostracism condition showed greater facial mimicry at posttest than toddlers in the control condition, as indicated by both EMG and behavioral coding measures. Although the exact mechanism underlying this result needs to be investigated in future studies, this finding is consistent with social affiliation accounts of mimicry and suggests that mimicry may play a key role in maintaining affiliative bonds when toddlers perceive the risk of social exclusion.

Normative Trends in Physically Aggressive Behavior: Age-Aggression Curves from 6 to 24 Months.

OBJECTIVE: To investigate age-related trends in physically aggressive behaviors in children before age 2 years. STUDY DESIGN: A normative US sample of 477 mothers of 6- to 24-month-old children reported on the frequency of 9 interpersonally directed aggressive child behaviors, and hurting animals, in the past month. RESULTS: Almost all (94%) of the children were reported to have engaged in physically aggressive behavior in the past month. Based on 2-part regression models, the prevalences of kicking (OR, 1.70; P = .023), pushing (OR, 3.22; P < .001), and swiping (OR, 1.78; P = .018) increased with years of age, but the prevalence of hair pulling decreased with age (OR, 0.55; P = .020). The prevalences of hitting and throwing increased initially, then plateaued at age 18-20 months, and then decreased (quadratic aOR, 0.13 and 0.16; P < .001 and .010, respectively). The frequencies of hitting (R2 = .05; P < .001) and throwing (R2 = .03; P = .030) increased, and the frequencies of hair pulling (R2 = .07; P < .001) and scratching (R2 = .02; P = .042) decreased with age (P values adjusted for false discovery rate). CONCLUSIONS: Physically aggressive behavior in the 6- to 24-month age range appears to be nearly ubiquitous. Most, but not all, forms of physical aggression increase with age. These results can guide pediatricians as they educate and counsel parents about their child's behavior in the first 2 years of life.

Gaps and Factors Related to Receipt of Care within a Medical Home for Toddlers Born Preterm.

OBJECTIVE: To characterize gaps and factors related to receipt of care within a medical home for toddlers born preterm. STUDY DESIGN: Participants were 202 caregivers of children born at <35 weeks of gestation. At 10-16 months of corrected age, caregivers completed the National Survey of Children's Health (2011/2012) medical home module and a sociodemographic profile. Care within a medical home comprised having a personal doctor/nurse, a usual place for care, effective care coordination, family-centered care, and getting referrals when needed. Gestational age and neonatal follow-up clinic attendance were abstracted from the medical record. The Bayley Scales of Infant and Toddler Development, Third Edition assessed developmental status. Log-binomial regression examined factors related to receiving care within a medical home. RESULTS: Fifty-three percent (n = 107) of the children received care within a medical home. Low socioeconomic status (young caregiver: risk ratio [RR] = 0.73; 95% CI 0.55, 0.97; low education: RR= 0.69; 95% CI 0.49, 0.98) and delayed language (RR = 0.63; 95% CI 0.42, 0.95) were associated with a lower likelihood of receiving care within a medical home. Degree of prematurity and neonatal clinic follow-up participation were unrelated to receipt of care within a medical home. CONCLUSIONS: Receipt of care within a medical home was lacking for nearly one-half of preterm toddlers, especially those with lower socioeconomic status and poorer developmental status. Discharge from a neonatal intensive care unit may be an optimal time to facilitate access to a primary care medical home and establish continuity of care. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01576783.

Parental gentle encouragement promotes shy toddlers' regulation in social contexts.

Gentle encouragement to approach appears to reduce risk for anxiety and is commonly incorporated into parenting interventions for inhibited preschoolers, yet little is known regarding whether gentle encouragement facilitates in-the-moment regulation as shy or inhibited children face social novelty, particularly during the toddler period. The current study used a sample of 55 temperamentally shy toddlers (21-24 months old) to examine toddler regulation in novel social contexts in relation to parental gentle encouragement to engage. Contexts included low-threat social novelty (i.e., a clown and puppets) and moderately threatening social novelty (i.e., strangers). Using an experimental design, parents were randomly assigned to provide behaviors thought to represent gentle encouragement: warm responsiveness to toddler fear and encouragement of toddler autonomy, prompt to engage, both warmth and prompt, or remaining uninvolved (no-encouragement control). Relative to toddlers in the no-encouragement control condition, toddlers whose parents were instructed to provide warmth showed less fear and more engagement in moderately threatening social contexts, and toddlers whose parents were instructed to provide both warmth and prompts showed greater suppression of respiratory sinus arrhythmia in low-threat social contexts. Findings suggest that parental gentle encouragement may promote regulated responses in social contexts in shy toddlers. Encouragement of toddler autonomy and warm responsiveness to toddlers in particular may help shy toddlers to engage with, rather than withdraw from, new people.

The Impact of a Preventive Intervention on Persistent, Cross-Situational Early Onset Externalizing Problems.

The Nurse-Family Partnership (NFP) home visiting intervention for low-income first-time mothers was evaluated for its preventive impact on persistent, cross-situational early-onset externalizing problems (EXT). Seven hundred thirty-five women in the Denver, CO, area were randomly assigned into one of two active conditions (nurse or paraprofessional home visiting from pregnancy through child age 2) or a control group in which children were screened and referred for behavioral and developmental problems. Externalizing behavior was assessed by parent report when the children were 2, 4, 6, and 9 years old; teachers provided reports at ages 6 and 9. Latent profile analyses suggested the presence of persistent, cross-situational early onset EXT in approximately 6 to 7% of girls and boys. The intervention deflected girls away from these EXT and toward a pattern marked by a persistent moderate elevation of externalizing behavior that was evident at home and not at school. This finding should be interpreted cautiously given the small number of girls with the elevated EXT. Surprisingly, the intervention also moved girls away from stable low level externalizing behavior toward the moderately elevated pattern. Both of the significant effects on girls' externalizing behavior were modest. No statistically significant effects were found for boys' externalizing behaviors, which exhibited a somewhat different patterning across time and reporter. Effect sizes were generally similar for the nurse and paraprofessional-visited groups. The results are discussed in the context of prior efforts to prevent early EXT and emerging evidence on the normative development of externalizing behavior.