A categorical approach to infants' individual differences during the Still-Face paradigm

Cluster analysis was used to create patterns of individual differences reflecting infant behaviors during the initial interaction episode of the Face-to-Face Still-Face (FFSF) paradigm. The clusters were used as the basic unit of analysis for studying infant and maternal behavior and dyadic coordination (i.e., matching and reparation) across FFSF. Seventy-five 4-month-old infants participated with their mothers. Cluster analysis identified three patterns: a Socially Engaged cluster (33%) exhibited high levels of social engagement with their mothers; a Disengaged cluster (60%) showed a tendency to be low in social interaction and a Negatively Engaged cluster (7%) showed high negative emotionality. During the Still-Face episode, the Socially Engaged cluster reacted by reducing focus on their mother and shifting their attention elsewhere, while infants in the Disengaged cluster reduced focus on the environment. Although both the Socially Engaged and Disengaged clusters increased in negative emotionality during the Still-Face, the Socially Engaged group largely recovered during the Reunion, whereas the Disengaged group displayed more negative emotion. The Negatively Engaged cluster demonstrated high levels of negative affect throughout the entire procedure. Mothers of Negatively Engaged infants showed less positive engagement and more social monitoring than mothers in other clusters during all episodes. Dyadic interaction differed between groups, with greater levels of matching and reparations in the engaged group, less in the Disengaged group, and very little coordination in the Negatively Engaged cluster. Findings highlight the role of distinctive patterns of infants' individual differences in determining early dyadic functioning.