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Maternal responses to infant facial expressions were examined in two socioeconomically diverse samples of South African mothers (Study I, N = 111; and Study II, N = 214; age: 17-44 years) using pupil and gaze tracking. Study I showed increased pupil response to infant distress expressions in groups recruited from private as compared to public maternity clinics, possibly reflecting underlying differences in socioeconomic status (SES) across the groups. Study II, sampling uniformly low-SES neighborhoods, found increased pupil dilation and faster orientation to expressions of infant distress, but only in the highest income group. These results are consistent with maternal physiological and attentional sensitivity to infant distress cues but challenge the universality of this sensitivity across socioeconomic diversity.

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 Peter Rockers and colleagues design and evaluate a home visit intervention integrated into community health worker operations in South Africa. Author summary: Why was this study done?: Prior studies have demonstrated that home visit interventions delivered by community health workers (CHWs) can have a positive impact on child development. We integrated a home visit intervention into existing CHW operations in South Africa to generate evidence useful for local decision-making. A key innovation of this study was the inclusion of 2 markers of neural function as primary outcomes: electroencephalography (EEG) power and saccadic reaction time (SRT), an eye-tracking measure of visual processing speed. What did the researchers do and find?: We conducted a cluster-randomized controlled trial in rural South Africa. Intervention CHWs were trained on a job aid that included content focused on improving child development, for use during regular home visits with caregivers and young children. Control CHWs provided the local standard of care. We enrolled 607 caregiver–child dyads in 26 intervention clusters and 432 dyads in 25 control clusters at the start of the study. At endline, we assessed 432 intervention dyads (71%) and 332 control dyads (68%) to evaluate impact on child development outcomes. The home visit intervention decreased child SRT by 7 milliseconds, indicating improved neural function, but did not significantly impact linear growth or skills. What do these findings mean?: Our findings contribute important new evidence to a growing literature documenting the positive effects of home visit interventions on child development. Collecting markers of neural function in low-resource settings is feasible. [ABSTRACT FROM AUTHOR]

Infants are slower to disengage from faces than non-face patterns when distracted by novel competing stimuli. While this perceptual predilection for faces is well documented, its universality and mechanisms in relation to other aspects of attention are poorly understood. We analysed attention disengagement times for faces and non-face patterns in a large sample of 6-to 9-month-old infants (N = 637), pooled from eye tracking studies in socioculturally diverse settings (Finland, Malawi, South Africa). Disengagement times were classified into distinct groups of quick and delayed/censored responses by unsupervised clustering. Delayed disengagement was frequent for faces (52.1% of trials), but almost negligible for patterns (3.9% of trials) in all populations. The magnitude of this attentional bias varied by individuals, whereas the impact of situational factors and facial expression was small. Individual variations in disengagement from faces were moderately stable within testing sessions and independent from variations in disengagement times for patterns. These results point to a fundamental dissociation of face and pattern processing in infants and demonstrate that the bias for faces can be robust against distractors and habituation. The results raise the possibility that attention to faces varies as an independent, early-emerging social trait in populations.

Background: Facial affect recognition (FAR) abilities underpin emotional intelligence (EI). The latter is suggested to predict academic success and to be important for clinician-patient interaction. It is therefore of interest to investigate the possible association between FAR and academic performance in undergraduate medical students., Methods: We assessed the association between the ability to recognize emotions through facial expression and exit examination performance, a measure of clinical proficiency, in undergraduate medical students stratified by gender at a South African tertiary institution using a prospective descriptive design. Data on the perception of facial expressions and exit examination marks were obtained from 144 (61%) females and 93 (39%) males with a mean age of 24.1 ± 1.6 years. Facial affect recognition measures on the Hexagon and Animation tasks were individually correlated with academic performance indicators using Pearson correlation., Results: The perceptual discrimination of anger was associated with improved performance in anaesthetics (r = .24; p = .004) and urology (r = .24; p = .001), while the recognition of happiness was associated with decreased performance in obstetrics (r = -.21, p = .002). Gender was an effect modifier in the relationship between perceptual discrimination of anger and urology performance (p = .03), with a strong positive relationship for males, but a non-significant relationship for females., Conclusion: There was no overall correlation between FAR and overall academic performance or with gender. However, subject (specialty) specific findings with recognition of specific emotions and with gender as effect modifier poses interesting questions about EI and FAR and prompts further research into FAR as a useful tool. Being an objective test and offering a more focused assessment makes FAR worthy of further application.

The present study in an African Xhosa sample examined whether familial vulnerability to schizophrenia is associated with deficits in facial affect recognition. Healthy comparison subjects, unaffected siblings of schizophrenia patients, and schizophrenia patients were tested with a task requiring rapid recognition of matched positive (happy), negative (angry), and neutral facial expressions. Siblings and patients demonstrated impaired recognition of negative relative to positive facial expressions whereas comparison subjects recognized negative and positive expressions at an equal level of accuracy. These results suggest that deficits in the processing negative affect from social cues are transmitted in families and may represent a heritable endophenotype of schizophrenia.