Leveraging machine learning to study how temperament scores predict pre-term birth status.

Background: Preterm birth (birth at <37 completed weeks gestation) is a significant public heatlh concern worldwide. Important health, and developmental consequences of preterm birth include altered temperament development, with greater dysregulation and distress proneness. Aims: The present study leveraged advanced quantitative techniques, namely machine learning approaches, to discern the contribution of narrowly defined and broadband temperament dimensions to birth status classification (full-term vs. preterm). Along with contributing to the literature addressing temperament of infants born preterm, the present study serves as a methodological demonstration of these innovative statistical techniques. Study design: This study represents a metanalysis conducted with multiple samples (N = 19) including preterm (n = 201) children and (n = 402) born at term, with data combined across investigations to perform classification analyses. Subjects: Participants included infants born preterm and term-born comparison children, either matched on chronological age or age adjusted for prematurity. Outcome measures: Infant Behavior Questionnaire-Revised Very Short Form (IBQ-R VSF) was completed by mothers, with factor and item-level data considered herein. Results and conclusions: Accuracy estimates were generally similar regardless of the comparison groups. Results indicated a slightly higher accuracy and efficiency for IBQR-VSF item-based models vs. factor-level models. Divergent patterns of feature importance (i.e., the extent to which a factor/item contributed to classification) were observed for the two comparison groups (chronological age vs. adjusted age) using factor-level scores; however, itemized models indicated that the two most critical items were associated with effortful control and negative emotionality regardless of comparison group.

Early Family Experiences and Neural Activity in Rural Pakistani Children: The Differential Role of Gender.

Adversity within low- and middle-income countries (LMICs) poses severe threats to neurocognitive development, which can be partially mitigated by high-quality early family experiences. Specifically, maternal scaffolding and home stimulation can buffer cognitive development in LMIC, possibly by protecting underlying neural functioning. However, the association between family experiences and neural activity remains largely unexplored in LMIC contexts. This study explored the relation of early family experiences to later cognitive skills and absolute gamma power (21-45 Hz), a neural marker linked to higher-order cognitive skills. Drawing data from the PEDS trial, a longitudinal study in rural Pakistan, we examined maternal scaffolding at 24 months and home stimulation quality at 18 months as predictors of verbal IQ, executive functions, and absolute gamma at 48 months for 105 mother-child dyads (52 girls). Maternal scaffolding interacted with gender to predict absolute gamma power, such that higher maternal scaffolding was related to higher gamma more strongly for girls. Maternal scaffolding also interacted with absolute gamma to predict executive functions, such that higher gamma was related to better executive functions only when maternal scaffolding was average to high. Individual differences in early family experiences may partially buffer the neural underpinnings of cognitive skills from adversity in LMIC.

Neonatal Physical Growth Predicts Electroencephalography Power in Rural South African Children.

Anthropometric measures at birth, indexing prenatal growth, are associated with later cognitive development. Children in low- and middle-income countries (LMIC) are at elevated risk for impaired prenatal and early postnatal growth and enduring cognitive deficits. However, the associations of neonatal physical growth with neural activity are not well-characterized in LMIC contexts, given the dearth of early childhood neuroimaging research in these settings. The current study examined birth length, weight, and head circumference as predictors of EEG relative power over the first three years of life in rural Limpopo Province, South Africa, controlling for postnatal growth and socioeconomic status (SES). A larger head circumference at birth predicted lower relative gamma power, lower right hemisphere relative beta power, and higher relative alpha and theta power. A greater birth length also predicted lower relative gamma power. There were interactions with timepoints such that the associations of birth head circumference and length with EEG power were most pronounced at the 7-month assessment and were attenuated at the 17- and 36-month assessments. The results identify birth head circumference and length as specific predictors of infant neural activity within an under-resourced context.

The development and diversity of religious cognition and behavior: Protocol for Wave 1 data collection with children and parents by the Developing Belief Network.

The Developing Belief Network is a consortium of researchers studying human development in diverse social-cultural settings, with a focus on the interplay between general cognitive development and culturally specific processes of socialization and cultural transmission in early and middle childhood. The current manuscript describes the study protocol for the network's first wave of data collection, which aims to explore the development and diversity of religious cognition and behavior. This work is guided by three key research questions: (1) How do children represent and reason about religious and supernatural agents? (2) How do children represent and reason about religion as an aspect of social identity? (3) How are religious and supernatural beliefs transmitted within and between generations? The protocol is designed to address these questions via a set of nine tasks for children between the ages of 4 and 10 years, a comprehensive survey completed by their parents/caregivers, and a task designed to elicit conversations between children and caregivers. This study is being conducted in 39 distinct cultural-religious groups (to date), spanning 17 countries and 13 languages. In this manuscript, we provide detailed descriptions of all elements of this study protocol, give a brief overview of the ways in which this protocol has been adapted for use in diverse religious communities, and present the final, English-language study materials for 6 of the 39 cultural-religious groups who are currently being recruited for this study: Protestant Americans, Catholic Americans, American members of the Church of Jesus Christ of Latter-day Saints, Jewish Americans, Muslim Americans, and religiously unaffiliated Americans.

Perceptions of HIV and Mental Illness as "Western" or "Traditional" Illnesses: A Cross-Sectional Study from Limpopo Province, South Africa.

Although Western biomedical treatment has dramatically increased across sub-Saharan African health systems, traditional medicine as a form of healing and beliefs in supernatural powers as explanations for disease remain prevalent. Research in this region has identified HIV in particular as a disease located within both the traditional African and Western medical paradigms, whilst mental illness is ascribed to primarily supernatural causes. Within this context, this study sought to understand and explore the perceptions of HIV and mental illness among a population of rural women in Limpopo, South Africa. 82 in-depth interviews were conducted between January and December, 2022. Interviews were transcribed and translated into English. Data were managed using NVivo 11 software and thematically analyzed. The majority of participants identified HIV as a Western illness requiring biomedical treatment with causation largely attributed to biological mechanisms. A traditional form of HIV only cured using traditional treatments was also denoted. Unlike for HIV, the majority of respondents felt that there was no biological or behavioral cause for mental illness but rather the illness was conceptualized supernaturally thus likely impacting patient care pathways. Further research to study HIV and mental health perceptions among a larger sample in different regions of sub-Saharan Africa is warranted.

Evaluation of a community health worker home visit intervention to improve child development in South Africa: A cluster-randomized controlled trial.

BACKGROUND: Effective integration of home visit interventions focused on early childhood development into existing service platforms is important for expanding access in low- and middle-income countries (LMICs). We designed and evaluated a home visit intervention integrated into community health worker (CHW) operations in South Africa. METHODS AND FINDINGS: We conducted a cluster-randomized controlled trial in Limpopo Province, South Africa. CHWs operating in ward-based outreach teams (WBOTs; clusters) and caregiver-child dyads they served were randomized to the intervention or control group. Group assignment was masked from all data collectors. Dyads were eligible if they resided within a participating CHW catchment area, the caregiver was at least 18 years old, and the child was born after December 15, 2017. Intervention CHWs were trained on a job aid that included content on child health, nutrition, developmental milestones, and encouragement to engage in developmentally appropriate play-based activities, for use during regular monthly home visits with caregivers of children under 2 years of age. Control CHWs provided the local standard of care. Household surveys were administered to the full study sample at baseline and endline. Data were collected on household demographics and assets; caregiver engagement; and child diet, anthropometry, and development scores. In a subsample of children, electroencephalography (EEG) and eye-tracking measures of neural function were assessed at a lab concurrent with endline and at 2 interim time points. Primary outcomes were as follows: height-for-age z-scores (HAZs) and stunting; child development scores measured using the Malawi Developmental Assessment Tool (MDAT); EEG absolute gamma and total power; relative EEG gamma power; and saccadic reaction time (SRT)-an eye-tracking measure of visual processing speed. In the main analysis, unadjusted and adjusted impacts were estimated using intention-to-treat analysis. Adjusted models included a set of demographic covariates measured at baseline. On September 1, 2017, we randomly assigned 51 clusters to intervention (26 clusters, 607 caregiver-child dyads) or control (25 clusters, 488 caregiver-child dyads). At endline (last assessment June 11, 2021), 432 dyads (71%) in 26 clusters remained in the intervention group, and 332 dyads (68%) in 25 clusters remained in the control group. In total, 316 dyads attended the first lab visit, 316 dyads the second lab visit, and 284 dyads the third lab visit. In adjusted models, the intervention had no significant impact on HAZ (adjusted mean difference (aMD) 0.11 [95% confidence interval (CI): -0.07, 0.30]; p = 0.220) or stunting (adjusted odds ratio (aOR) 0.63 [0.32, 1.25]; p = 0.184), nor did the intervention significantly impact gross motor skills (aMD 0.04 [-0.15, 0.24]; p = 0.656), fine motor skills (aMD -0.04 [-0.19, 0.11]; p = 0.610), language skills (aMD -0.02 [-0.18, 0.14]; p = 0.820), or social-emotional skills (aMD -0.02 [-0.20, 0.16]; p = 0.816). In the lab subsample, the intervention had a significant impact on SRT (aMD -7.13 [-12.69, -1.58]; p = 0.012), absolute EEG gamma power (aMD -0.14 [-0.24, -0.04]; p = 0.005), and total EEG power (aMD -0.15 [-0.23, -0.08]; p < 0.001), and no significant impact on relative gamma power (aMD 0.02 [-0.78, 0.83]; p = 0.959). While the effect on SRT was observed at the first 2 lab visits, it was no longer present at the third visit, which coincided with the overall endline assessment. At the end of the first year of the intervention period, 43% of CHWs adhered to monthly home visits. Due to the COVID-19 pandemic, we were not able to assess outcomes until 1 year after the end of the intervention period. CONCLUSIONS: While the home visit intervention did not significantly impact linear growth or skills, we found significant improvement in SRT. This study contributes to a growing literature documenting the positive effects of home visit interventions on child development in LMICs. This study also demonstrates the feasibility of collecting markers of neural function like EEG power and SRT in low-resource settings. TRIAL REGISTRATION: PACTR 201710002683810; https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=2683; South African Clinical Trials Registry, SANCTR 4407.

Vaccination coverage at seven months of age in Limpopo Province, South Africa: a cross-sectional survey.

Many low- and middle-income countries face challenges in attaining adequate levels of vaccination coverage, and the factors driving this under-coverage have not been completely elucidated. In this cross-sectional study, we investigated factors associated with vaccination coverage in Mopani District, Limpopo Province, South Africa. Between July and October 2017, we surveyed 317 caregivers (83% of whom were mothers) of seven-month-old infants in Mopani District about barriers faced when attaining vaccines and attitudes towards vaccination, and reviewed the infants' documented vaccination history. Caregiver and child demographic data were collected shortly after birth. We described the coverage for vaccines that should be received by age seven months, according to South Africa's Expanded Programme on Immunization schedule, and explored the relationship between coverage and caregiver characteristics, behavioral factors (e.g. attitudes towards vaccination), and structural factors (e.g. vaccination stock-outs at clinics). We found that caregivers reported positive attitudes towards vaccination, based on a seven-question survey of vaccination attitudes. Although coverage was high for most recommended vaccines, it was low for pneumococcal conjugate vaccine (PCV), with just 36% of children having received it by age seven months. This appears to have been due to PCV stock-outs at government clinics. For vaccines other than PCV, children were more likely to be up-to-date on vaccinations if a community health worker (CHW) had visited their home in the past month (adjusted odds ratio (OR) 1.24, confidence interval (CI) (1.10-1.41); p < 0.001) and if the caregiver had more years of schooling (adjusted OR 1.03 (CI 1.01-1.05); p = 0.012). We conclude that addressing PCV stock-outs at government clinics in Mopani District is necessary to ensure coverage reaches adequate levels. Additionally, supporting CHW programs may be a productive avenue for improving vaccination coverage.

Infants' neural sensitivity to social interactions varies by income and infant-directed speech.

Social interactions are essential for infant brain development, yet we know little about how infant functional connectivity differs between social and nonsocial contexts, or how sensitivity to differences between contexts might be related to early distal and proximal environmental factors. We compared 12-month-old infants' intrahemispheric electroencephalographic (EEG) coherence between a social and a nonsocial condition, then examined whether differences between conditions varied as a function of family economic strain and two maternal behaviors at 6 months, positive affect and infant-directed speech. We found lower EEG coherence from the frontal region to the central, parietal, temporal, and occipital regions during the social condition, but only for infants from higher-income families and infants whose mothers used higher proportions of infant-directed speech. In contrast, there were no differences between social and nonsocial conditions for infants from economically strained families or infants whose mothers used lower proportions of infant-directed speech. This study demonstrates that neural organization differs between a nonsocial baseline and a social interaction, but said differentiation is not present for infants from less privileged backgrounds. Our results underscore the importance of examining brain activity during species-typical contexts to understand the role of environmental factors in brain development.

Social Fear in US Infants: The Roles of Hair and Salivary Cortisol.

Elevated social fear in infancy poses risk for later social maladjustment and psychopathology. Hair cortisol concentration (HCC), an index of cumulative cortisol exposure, and diurnal salivary cortisol slope, a biomarker of acute stress regulation, have been associated with social fear behaviors in childhood; however, no research has addressed their relations in infancy. Elucidating potential biomarkers of infant social fear behaviors, as well as environmental factors associated with these biomarkers, may grant insights into the ontogeny of fear behaviors that increase risk for internalizing and externalizing psychopathologies later in life. The current study used multiple linear regression to examine if infant HCC, infant diurnal cortisol slope, and income-to-needs ratios (ITN) were differentially associated with observed social fear responses to a Stranger Approach task at 12 months. Using a sample of 90 infants (Mage = 12.26m, SD = 0.81m, 50% female), results indicated that increased infant HCC was associated with increased distress vocalizations during the Stranger Approach task, while steeper diurnal cortisol slope was associated with fewer distress vocalizations. Ordinary least squares path analyses did not reveal group differences between economically strained and non-strained infants in how cortisol measures and social fear responses related. Findings underscore very early psychobiological correlates of fearfulness that may increase risk for fear-related disorders and adverse mental health symptomology across childhood.

Relationships Among Childhood Maltreatment, Limbic System Dysfunction, and Eating Disorders in College Women.

The mechanisms linking childhood maltreatment and eating pathology are not fully understood. We examined the mediating role of limbic system dysfunction in the relationships between three forms of childhood maltreatment (parental psychological maltreatment, parental physical maltreatment, and parental emotional neglect) and eating disorder symptoms. A convenience sample of college women (N = 246, M age = 19.62, SD = 2.41) completed measures of maltreatment (Parent-Child Conflict Tactics Scales and the Parental Bonding Instrument), limbic system dysfunction (Limbic System Questionnaire), and eating pathology (Eating Disorder Examination Questionnaire). We hypothesized that there would be an indirect effect of each type of childhood maltreatment on eating disorder symptoms via limbic system irritability. Results generally supported the hypotheses. Examination of the individual paths that defined the indirect effect indicated that higher reported childhood maltreatment was associated with greater limbic irritability symptoms, and higher limbic irritability symptomatology was related to higher total eating disorder scores. There were no significant direct effects for any of the proposed models. Findings are in line with research supporting the role of limbic system dysfunction as a possible pathway in the maltreatment-eating disorder link. Given that limbic system dysfunction may underlie behavioral symptoms of eating disorders, efforts targeting limbic system dysfunction associated with child maltreatment might best be undertaken at an early developmental stage, although interventions for college women struggling with eating disorders are also crucial.

Infant diurnal cortisol predicts sleep.

The sleep-wake system is immature at birth and develops in parallel with the hypothalamic-pituitary-adrenal axis, a biological stress system of which the end product is cortisol. Perturbations in one system during infancy can maladaptively influence the maturation of the other system, leading to lasting sleep and cortisol system dysregulation and heightening the risk of enduring health problems. To better understand the early interplay between these systems, we examined whether actigraphy-derived measures of night-time sleep duration and onset were associated with cumulative exposure to cortisol, indexed by hair cortisol concentration, in 12-month-old children. Overall, early sleep onset predicted lower hair cortisol above and beyond sleep duration, family income and chaos experienced at home. Furthermore, both sleep and cortisol levels vary day to day, and temporal dependencies between daily sleep and cortisol regulation are not well understood. Thus, we assessed how the sleep characteristics on a particular evening related to salivary cortisol levels the following day and how daytime and evening cortisol related to the sleep characteristics on the same night. Lower total exposure to cortisol on a particular day was related to longer night-time sleep duration the same night, but not sleep onset. Lower salivary cortisol levels on a given evening related to earlier sleep onset the same night, but not to night-time sleep duration. Sleep duration and onset on a given night were unrelated to total cortisol exposure the following day. Findings suggest that in early development, the day-to-day relation between sleep and cortisol is not bidirectional, but more driven by diurnal cortisol.

Maternal expressive suppression moderates the relations between maternal and child hair cortisol.

Self-reports and physiological indicators of stress such as cortisol levels are correlated in maternal and child samples. This relationship is likely to be influenced by maternal emotion regulation. Herein, we investigate the moderating role of maternal regulation strategies on the association between maternal and child hair cortisol levels. Mother-child dyads (N = 63, child mean age = 49.74 months) participated in the study. Hair samples were collected from mother and child, and cortisol was assayed. Mothers reported on their own emotion regulation strategies, namely expressive suppression and cognitive reappraisal. As expected, mother and child hair cortisol levels were significantly correlated. Interestingly, the relation between maternal and child hair cortisol was moderated by maternal suppression of emotion. Mother and child hair cortisol levels were related at low levels of maternal suppression, but not at higher levels of suppression. Maternal cognitive reappraisal of emotion was not associated with cortisol levels.

Consistency in maternal affect and positive vocalization over the first year of life.

Consistency in parenting infants has positive developmental outcomes. Yet, the role of socioeconomic status (SES) in consistency of maternal behaviors is not well understood. We investigated individual-order continuity of maternal smile and laughter and positive vocalization from 6 to 12 months of age in 82 mother-infant dyads. Overall, individual differences in maternal smile and laughter, and positive vocalization were consistent across time. A multidimensional measure of SES moderated the association of maternal smile and laughter from 6 to 12 months, such that infants from lower SES families were vulnerable to unpredictable parenting - experiencing a lack of consistency in maternal smiles and laughter.

Neural mechanisms of response-preparation and inhibition in bilingual and monolingual children: Lateralized Readiness Potentials (LRPs) during a nonverbal Stroop task.

Inhibitory control is a core executive function (EF) skill, thought to involve cognitive 'interference suppression' and motor 'response inhibition' sub-processes. A few studies have shown that early bilingualism shapes interference suppression but not response inhibition skills, however current behavioral measures do not fully allow us to disentangle these subcomponents. Lateralized Readiness Potentials (LRPs) are centroparietal event-related potentials (ERPs) that track motor response-preparations between stimulus-presentation and behavioral responses. We examine LRPs elicited during successful inhibitory control on a nonverbal Stroop task, in 6-8 year-old bilingual (n = 44) and monolingual (n = 48) children from comparable socio-economic backgrounds. Relative to monolinguals, bilinguals showed longer and stronger incorrect-response preparations, and a more mature pattern of correct-response preparation (shorter peak-latencies), underlying correct responses on Stroop-interference trials. Neural markers of response-inhibition were comparable between groups and no behavioral differences were found between-groups on the Stroop task. Results suggest group differences in underlying mechanisms of centroparietal motor-response preparation mechanisms in this age group, contrary to what has been shown using behavioral tasks previously. We discuss neural results in the context of speed-accuracy trade-offs. This is the first study to examine neural markers of motor-responses in bilingual children.

Cortisol and socioeconomic status in early childhood: A multidimensional assessment.

The hypothalamic-pituitary-adrenal (HPA) axis is sensitive to early life stress, with enduring consequences for biological stress vulnerability and health (Gunnar & Talge, 2008). Low socioeconomic status (SES) is associated with dysregulation of the stress hormone cortisol in early childhood. However, a mechanistic understanding of this association is lacking. Multidimensional assessment of both SES and cortisol is needed to characterize the intricate relations between SES and cortisol function in early childhood. We assessed parent-reported family income, parent education, occupational prestige, neighborhood risk, food insecurity, and household chaos for 12-month-old infants (N = 90) and 3.5-year-old children (N = 91). Hair cortisol concentration (HCC) was obtained from parent and child, indexing chronic biological stress, and diurnal salivary cortisol was measured in the children. Controlling for parent HCC, parent education uniquely predicted infant and child HCC and, in addition, neighborhood risk uniquely predicted infant HCC. Household chaos predicted bedtime salivary cortisol concentration (SCC) for both infants and children, and infant daily cortisol output. Food insecurity was associated with flattened cortisol slope in 3.5-year-old children. Parental sensitivity did not mediate relations between SES and cortisol. Results highlight the utility of SES measures that index unpredictable and unsafe contexts, such as neighborhood risk, food insecurity, and household chaos.

Parental and Family-Level Sociocontextual Correlates of Emergent Emotion Regulation: Implications for Early Social Competence.

OBJECTIVES: Emotion regulation skills in early childhood are essential for healthy emotional and behavioral development, yet factors related to emergent emotion regulation during the early preschool period have not been extensively explored. METHODS: In the present study (N = 90), we specifically examine parental and family-level sociocontextual correlates in relation to emotion regulation skills in three-year-olds, a crucial time when the onset of several cognitive and socioemotional abilities are intertwined. We also investigate the role of these developing emotion regulatory capacities with behavioral problems and social competence. RESULTS: Children whose parents use more adaptive emotion regulation strategies (r = .33, p = .001) and who grow up in a higher income (r = .25, p = .02), less chaotic household (r = -.30, p = .004) have better emergent emotion regulation. Additionally, better child emotion regulation skills are associated with more positive outcomes such as fewer behavioral problems (r = -.46, p < .001) and more instrumental helping behaviors (r = .23, p = .04). CONCLUSIONS: Findings indicate that identifying individual differences in emotion regulation earlier than most prior studies may be particularly important for fostering this crucial skill and overall psychological well-being in young children.

Socioeconomic status and neural processing of a go/no-go task in preschoolers: An assessment of the P3b.

While it is well established that lower socioeconomic status (SES) is associated with poorer executive functioning (EF), how SES relates to the neural processing of EF in childhood remains largely unexplored. We examined how household income and parent education related to amplitudes of the P3b, an event-related potential component, during one EF task. We assessed the P3b, indexing inhibition and attention allocation processes, given the importance of these skills for academic success. Children aged 4.5-5.5 years completed a go/no-task, which assesses inhibitory control and attention, while recording EEG. The P3b was assessed for both go trials (indexing sustained attention) and no-go trials (indexing inhibition processes). Higher household income was related to larger P3b amplitudes on both go and no-go trials. This was a highly educated sample, thus results indicate that P3b amplitudes are sensitive to household income even within the context of high parental education. Findings build on the behavioral literature and demonstrate that SES also has implications for the neural mechanisms underlying inhibition and attention processing in early childhood.

Emotion regulation moderates the association between parent and child hair cortisol concentrations.

Successful emotion regulation facilitates children's coping with everyday stress. It develops rapidly in the early preschool period. However, no work has been done to investigate the potential buffering role of emotion regulation from cumulative physiological effects of stress. In this study, we examined hair cortisol concentration (HCC), an early marker of chronic physiological stress, socioeconomic status (SES), parental sensitivity, and emotion regulation and reactivity in a sample of 3.5-year-old children (N = 86). Emotion regulation and emotional reactivity were independent of child HCC. However, emotion regulation moderated the relationship between parent and child HCC. For children with better emotion regulation, there was no association between parent and child HCC, suggesting that emotion regulation skills buffered the transgenerational effects of chronic physiological stress. Emotional reactivity moderated the relationship between SES and child HCC, and attenuated the association between parental sensitivity and child HCC. Taken together, these findings demonstrate that children who were less emotionally reactive were less susceptible to their environments. Results provide support that child emotion regulation and emotional reactivity can reduce or strengthen the relationship between established risk factors and levels of chronic physiological stress in early childhood.

A systematic assessment of socioeconomic status and executive functioning in early childhood.

Lower socioeconomic status (SES) consistently relates to poorer executive function (EF). This study used a systematic and nuanced approach to understand how SES relates to children's EF at a process level. We assessed children aged 4.5-5.5 years. This is a key developmental period because EF is no longer a unitary construct but rather EF components statistically load on separate factors and index distinct aspects of EF. Children completed a working memory task that involved a cognitive load component and a go/no-go task to assess inhibitory control and vigilance. Accuracy and reaction time were assessed, and each task involved four blocks to assess performance over time. Lower SES related to lower accuracy for working memory, inhibitory control, and vigilance as well as slower reaction time for working memory. SES did not relate to go/no-go reaction time. For working memory, lower SES related to poorer accuracy on lower cognitive load trials, but there were no SES differences on higher cognitive load trials. SES did not relate to maintenance of performance over time. Results suggest that for this age group the majority of domains showed SES differences. However, there were no SES differences in performance for remembering two items and maintaining performance. Thus, although overall lower SES related to poorer EF performance, there were no SES effects for skills that are still emerging for all children, namely, maintaining task performance across time and remembering two items at once. Results highlight the importance of assessing EF as a multidimensional construct and may help to identify targets for intervention.

Varieties of Young Children's Prosocial Behavior in Zambia: The Role of Cognitive Ability, Wealth, and Inequality Beliefs.

By the 3rd year of life, young children engage in a variety of prosocial behaviors, including helping others attain their goals (instrumental helping), responding to others' emotional needs (comforting), and sharing resources (costly giving). Recent work suggests that these behaviors emerge early, during the first 2 years of life (Svetlova et al., 2010; Thompson and Newton, 2012; Dunfield and Kuhlmeier, 2013). To date, however, work investigating early varieties of prosocial behavior has largely focused on Western samples and has not assessed the impact of poverty and inequality. In this work, we investigate prosocial behavior in 3-year-olds in Zambia, a lower-middle income country with high wealth inequality. Experiments were integrated into a larger public health study along with both objective and subjective (parent) measures of wealth and inequality. Three-hundred-seventy-seven children (Mean age = 36.77 months; SD = 2.26 months) were presented with an instrumental helping task, comforting task, and two steps of a giving task - one with higher cost (children could give away their only resource) and one with lower cost (children had three resources to give). As predicted, rates of prosociality varied hierarchically by the cost of the action: instrumental helping was the most common followed by comforting, lower cost giving, and higher cost giving. All prosocial behaviors were significantly correlated with one another (with the exception of high cost giving), and with general cognitive ability. Objective family wealth did not predict any of the child's prosocial behaviors. However, subjective beliefs showed that mothers who believed that they had more than others in their village had children who were more likely to engage in instrumental helping, and mothers who believed that village inequality was a problem had children who were more likely to engage in low cost giving. Low cost giving was also more likely for children whose parents reported reading storybooks to them. This suggests that costly giving in the context of pretend play may relate to children's experience with using stories as representations of real life events. The results suggest both cultural differences and universalities in the development of prosociality and point to environmental factors that influence prosociality.