Measuring temperament in developmental research: A thin-slice approach to capturing temperament in infants and toddlers.

Temperament is a key factor in early development and predicts several key developmental outcomes. The ability to capture temperament in a variety of settings and ages is thus increasingly useful. Recent work has demonstrated the utility, reliability, and validity of thin-slice assessments in which brief snapshots of children's behavior are used to make inferences about general traits (Tackett et al., 2016). Thin-slice has been effective for assessing personality in older children (over 7-years; Tackett et al., 2016, 2017) and preschoolers 3-6 years old (Whalen et al., 2021) when engaging in lab tasks or clinical assessments. However, no work has examined the use of thin-slice for temperament in younger, typically developing infants/toddlers during lab-based tasks. The present study aims to test a downward extension of a modified thin-slice approach to assess temperament using archived videos of 516 infants/toddlers (n_female = 255; M_age = 27.51 months, Range_age = 17-47 months). Children were originally recruited from a range of socioeconomic backgrounds across the central United States and completed a short play session, which incorporated standard language and cognition tasks that were not designed to elicit temperament; caregivers also reported their children's temperament using the Early Child Behavior Questionnaire (Putnam & Rothbart, 2006). Naive raters scored the videos using a modification of the thin-slice approach. We find evidence of good reliability and validity for temperament scores using this approach suggesting thin-slice assessments are another method for measuring temperament in infants and toddlers. Moreover, thin-slice allows for post assessment of temperament even when it had not been formally assessed. (PsycInfo Database Record (c) 2024 APA, all rights reserved).