An exploration of relationships between infant temperament, facial expression and pacifier use

This thesis investigated how pacifier use relates to infant temperament and facial emotional expressivity, using two UK-based secondary datasets. In a large parent survey (N = 428), current pacifier use was linked to lower negative emotionality, and longer use to higher positive affectivity/surgency. In a smaller study with observational data (N = 64), longer use was associated with higher Orienting/Regulatory Capacity, and infants showed reduced facial expressivity when using a pacifier. No links emerged between observed expressivity and parent-reported temperament. Overall, findings suggest pacifiers may act as early regulatory tools, influencing both emotional tendencies and outward expression.