Infrared Thermal Imaging (ITI), a Non-invasive Window Into Early Emotion Regulation: A Systematic Review.

Investigating early emotion regulation abilities is crucial as they are key predictors of future socio-emotional development. Infrared thermal imaging (ITI) is a promising non-invasive technique for studying physiological regulation of socio-emotional states in children in both ecological and controlled settings. Despite its potential, no review has summarized the current evidence in the field. We performed a systematic review following the PRISMA guidelines to analyze temperature changes in response to socio-emotional stimuli in children aged 0-12 years. The search yielded 15 records, published between 1959 and 2023, including typically developing children (n = 13) and children with neurodevelopmental conditions (n = 2). The reviewed studies showed mixed results, with methodological quality ranging from weak to moderate. Temperature increases and decreases were reported across regions of interest, particularly in the face and hands, in response to negative and positive emotions elicited by face-to-face interactions and audio-visual stimuli. The limited evidence and methodological variability across studies prevent the identification of clear patterns in children's thermal responses to socio-emotional stimuli. Further rigorous research is needed to validate ITI as a reliable tool for exploring socio-emotional regulation in children with typical and atypical development.