Maternal and infant characteristics connected to shared pleasure in dyadic interaction.

The aim of the study was to analyze which maternal factors (depressive symptoms, effect of life events, maternal sensitivity and structuring) and infant characteristics (temperament, social withdrawal symptoms, interactive behavior, genotype, gender) contribute to shared pleasure (SP) in parent-infant interaction. Participants were 113 mother-infant dyads. The mothers filled in the Edinburgh Postnatal Depression Scale, the Infant Behavior Questionnaire, and the Life Events Questionnaire. The dyads were videotaped in a free-play situation, and the videos were analyzed using the Alarm Distress Baby Scale and the Emotional Availability Scales. The infants were genotyped for four genes involved in emotion regulation. The occurrence and duration of SP (SP-MD) in mother-infant interactions were analyzed from the videotapes. Higher maternal sensitivity and depressive symptoms, better infant responsiveness, and the infant having the GG variant of the gene tryptophan hydroxylase isoform 2 (TPH2) -307 were associated with the occurrence of SP. Lower level depressive symptoms, better maternal structuring, and greater infant involvement were associated with the longer duration of SP. Those dyads where the mother and infant were best able to read each other's positive cues and to respond to them were more likely to experience mutual positive affect, as seen in SP.