Emotional musicality in mother-infant vocal affect,and an acoustic study of postnatal depression

Abstract

Mother-Infant communication that satisfies both partners exhibits various musical elements. In cases where the mother is suffering from postnatal depression, qualities of rhythmic attunement, reciprocity and overall satisfaction with the interaction all decline. This case study reports detailed acoustic analysis of vocal interactions between a depressed mother and her infant at eight weeks and six months of age, and compares these with the same analysis of a healthy dyad at matching ages. Results showed the depressed mother to produce quieter, lower-pitched vocalisations, punctuated by longer pauses. Disruption was also evident in the depressed mother's turn-taking behaviour. Matching of pitch, low arousal, less “joining in” and negative mood states in the infant of the depressed mother suggested corresponding low affect in the baby. These characteristics of the depressed dyad's communication improved as clinical symptoms declined. Both dyads showed periodicity in timing of interactions, but this was considerably slower and less co-ordinated in the depressed pair. The control dyad produced more evidence of reciprocal, happy communication with regular timing and “singing” voice quality. These results present preliminary evidence of the importance of objectively defined features of communicative musicality in healthy, reciprocal interactions, and they highlight the part played by an innate pulse and shared timing within a musical framework in the organisation of the motives that regulate infant behaviours.