Baldwin, DareMeaselle, JeffreyGraboyes, MelissaRudolph, Jenna2021-07-272021-07-272021https://hdl.handle.net/1794/2655561 pagesMillions of Southeast Asian children are at risk for thiamine deficiency, which in turn puts their neuro-cognitive development in peril. Our study investigates the possibility that thiamine supplementation for Cambodian mothers protects infants’ cognitive development. Specifically, we examined the extent to which thiamine supplementation enhances infants’ alertness to caregivers’ efforts to engage. Such alert responsiveness indexes neuro-cognitive well-being, while also supporting further neuro-cognitive progress. As part of a larger, double-blind, randomized controlled trial, lactating mothers (N = 335) received one of four levels of thiamine supplementation (0, 1.2, 2.4, or 10mg/day) beginning at 2 weeks post-partum. We assessed infants’ alertness in relation to caregivers’ efforts to interact via a new method, the Primary Engagement Task (PET), when infants were 2-, 12-, and 24-weeks. In the PET, mothers were asked to coax a smile from infants, and sustain a mutually positive interaction. As the PET progressed, mothers were cued to add, then remove, engagement modalities during six 30-second epochs. Video coding determined changes in infants’ alertness across epochs. As predicted, infants’ alertness increased, then decreased (remaining higher than baseline) as the PET unfolded. Moreover, these patterns tended to become more pronounced with increasing age and were influenced by maternal thiamine supplementationen-USCC BY-NC-ND 4.0Developmental PsychologyMicronutrientsGlobal HealthThiamine DeficiencyMaternal and Infant HealthThesis/Dissertationhttps://orcid.org/0