Observations of the early interactions between the infant and his parents highlighted the existence of rhythmic and reciprocal communications that serve as a basis for the mother-baby relationship and the emotional and cognitive development of the baby. In this study, the investigator proposes to focus on premature births (before 37 years) because prematurity disrupts the synchronization of these mother-baby communication. For several years, reading of stories and nursery rhymes has been used by the liaison child psychiatry team in the neonatal medicine and pediatric intensive care unit of the University Hospital of Amiens, as a therapeutic mediation tool allowing And support for parent-child interactions. Thus, it is desirable to explore the impact of reading stories and rhymes on mother-baby synchronies. The study is innovative because it simultaneously explores several fields: physiological, neuroendocrine, cognitive and psychic. A pilot study carried out in 2013 showed the feasibility of this exploration in the three protagonists of the interaction: mother, preterm baby and reader.