When is the Still-Face not the Still-Face: mothers' behavior in the Face-to-Face Still-Face procedure and its relationship to infant arousal

The Face-to-Face Still-Face (FF-SF) procedure has been a popular paradigm to understand infant behavior. The current study examines the validity of mothers' behavior during the Still-Face phase of the FF-SF, especially the quality of her neutral face and its impact on infant arousal (N = 358 ethnically-diverse mother-infant dyads, Mean infant age = 223 days, SD = 27 days). Results showed that more than half of the mothers in the sample breached one or more Still-Face phase instructions; however, mothers' breaches of the Still-Face instructions were unrelated to infant arousal (Skin Conductance Responses) during the FF-SF. Additionally, facial analysis revealed that along with a neutral quality to the Still-Face, mothers also displayed significant levels of facial emotion during the Still-Face phase. Higher levels of scared and/or sad expressions during the Still-Face were associated with higher infant arousal during the Still-Face phase. The current study helps us to understand the real-life implementation of the Still-Face during the Face-to-Face Still-Face paradigm. Results indicate that mothers show considerable non-compliance with Still-Face phase instructions, and the infant arousal levels are associated with emotional expressions contaminating the quality of mothers' neutral faces.