Fear and fearlessness in infants: a developmental approach

The main aim of this thesis was to improve our understanding of the development of early inhibitory emotions and emotion regulation from infancy, and the role of these emotions in early risk pathways. More specifically, this thesis investigated (1) the development of fearful temperament, its stability over the first 3 years of life, and its associations with later developing effortful control (EC) and guilt; (2) risk factors in infancy that predict later externalising psychopathology; and (3) the development of EC, and its associations with fear and guilt. Psychophysiological and observational measures were used, when available, to examine these emotional systems as well as their role in predicting later psychopathology. The thesis consists of 3 empirical chapters, investigating a sample of 70 typically developing children in a longitudinal, prospective manner. Behavioural fear was stable over time, but physiological fear peaked in year 2. Fearful infants continued to be fearful toddlers, and fear in infancy predicted fearfulness 2 years later. Fear and guilt were associated, and we showed for the first time that infant fear is a predictor of later developing guilt. EC increased from year 2 to year 3, showed inter-individual stability across time, and girls’ ability for EC surpassed the ability in boys. EC and guilt were not associated; however, EC and fear were associated in year 3, suggesting that early fear does not regulate later EC. This thesis identified two biomarkers in infancy for later psychopathology. A subgroup of toddlers with internalising problems displayed higher heart rate in infancy, whereas skin conductance arousal in infancy predicted aggressive behaviour in toddlers.