Infant Socioemotional Responses When Faced with Social Threat: Implications For Neurophysiological and Bio-hormonal Processing

Infants have an innate desire to form social bonds and jealousy protests are an attempt to regain exclusive maternal attention from a social usurper. The current study examined neurophysiological and bio-hormonal processes related to jealousy responses during the first year and a half of life. Prior to and after the first year of life, infants express jealousy protest behavior when faced with a social threat. Resting-state frontal EEG coherence indicated a developmental shift from bilateral connectivity in younger infants to increased frontal specialization in older infants in relation to jealousy responses. Furthermore, 6- to 9-month-old infants exhibited more frontal neuroconnectivity in the right hemisphere (i.e., an area related to negative emotions) of the brain compared to left when faced with social threat. Lastly, social threat activated HPA reactivity in infants higher in temperamental distress. This study provides further evidence for the emerging links between physiological and socioemotional responses in infancy due to loss of exclusive maternal attention.