Developmental dynamics of positive and negative emotion in infancy.

The dynamic features of emotion-intensity, speed of response, rise time, persistence, recovery-are important to emotion development, but there remains limited understanding of early developmental changes in these dynamics and how they are organized. In this exploratory study, 58 White infants were observed at ages 6, 9, and 12 months in four social episodes designed to elicit positive emotion (two games with mother) and negative emotion (stranger approach and separation from mother). Continuous time-sampled ratings and summary assessments of facial and vocal responding yielded measures of onset intensity, peak intensity, onset latency, time to peak intensity, rise time, persistence, and recovery for each episode and expressive modality. Central findings indicated significant developmental increases in the intensity and speed of response for positive and negative episodes, but across age and expressive modality the organization of positive and negative responses differed consistently. Specifically, responses to negative emotion episodes reflected characteristics of a preemptory response to perceived threat (e.g., intensity positively correlated with persistence), while intense positive emotion involved quicker onset and longer rise time, consistent with establishing and maintaining social engagement. Implications of these findings and directions for further study are outlined. (PsycInfo Database Record (c) 2023 APA, all rights reserved).