Multisensory interactions are central to early development, yet their influence on newborns' tactile processing remains unclear. In particular, it is unknown whether auditory input interferes with or modulates tactile habituation, and how this depends on voice familiarity and temporal contingency. This study investigated these questions in 96 full-term newborns using a manual habituation-discrimination paradigm across four auditory conditions: silence, recorded stranger voice, recorded maternal voice, and live maternal voice contingent on the infant's object-holding behavior. Infants explored a smooth object until habituation, after which they were presented with a novel shape to assess discrimination. The presence of a voice generally reduced the proportion of infants reaching habituation compared to silence, with an apparent gradient from stranger to maternal to live contingent maternal voice; pairwise comparisons were significant only between silence and live contingent maternal conditions. Among infants who habituated, total holding time was significantly longer in the live contingent maternal voice condition, whereas initial holding times did not differ across conditions. No evidence of tactile discrimination was observed, likely reflecting the small number of infants completing the test phase. These findings indicate that auditory input, particularly when contingent on the infant's actions, strongly engages newborns' attention and behavior. Rather than merely interfering with tactile learning, live contingent maternal vocalizations may promote socio-emotional engagement and operant-like associations, redirecting attention toward salient cues. Overall, the results underscore the attentional salience of maternal vocal input and indicate that temporally contingent maternal speech can modulate newborns' engagement during tactile exploration, suggesting a potential influence on attentional and learning processes.

Maternal psychosocial stress during the perinatal period is a prevalent yet heterogeneous exposure associated with early developmental vulnerability. This longitudinal study examined the relationship between maternal perinatal psychosocial stress and infant neurodevelopmental profiles at three months of age in an Argentine cohort. A total of 198 mother-infant dyads were assessed during the second and third trimesters of pregnancy and at three months postpartum. Maternal stress was evaluated using validated measures of depression, anxiety, perceived stress, and pregnancy-specific distress. Infant neurodevelopment was assessed using the Ages and Stages Questionnaires 3. Principal component analyses were used to derive trimester-specific and cumulative stress indices, while latent profile analysis identified distinct neurodevelopmental subgroups. Two infant profiles emerged: typical neurodevelopment (84.8%) and neurodevelopmental risk (15.2%), characterized by uniformly lower scores across all developmental domains. Binary logistic regression analyses showed that higher maternal psychosocial stress during the second trimester was significantly associated with increased odds of infant neurodevelopmental risk, although effect sizes were modest. Stress during the third trimester, postnatally, and cumulative perinatal stress did not significantly predict risk. These findings support the existence of a sensitive gestational window during mid-pregnancy in which maternal psychosocial stress is most strongly linked to early neurodevelopmental vulnerability. By integrating variable-centered and person-centered approaches, this study highlights the multidimensional nature of perinatal stress and provides context-specific evidence from a low- and middle-income setting. Early screening and targeted interventions during pregnancy may contribute to reducing early developmental risk.