During the first six months of life, nonverbal expressions are the only form of communication for the baby. Through gestures and crying he expresses his needs, fears and anger.
Fathers, and according to studies more mothers than fathers, we have the ear tuned to identify each type of crying. We can differentiate crying from hunger from crying because of pain, even without seeing our baby's face. There are those who go to crying analyzers, but I doubt that they exceed the experience of the parents.
Yesterday a new study entitled "Gestural and Prosodic Communication of the Baby" was carried out by the Nuk Baby Institute and the Psychology Faculties of the Universities of Murcia, Valencia and the Distance Education in which analyzed the facial and vocal expression of babies between 3 and 12 months to decipher the gestural response to various emotions such as anger, sadness, fear, pain, disgust, surprise and joy.
They recorded the reaction of the babies to different situations and have been able to observe that for example, in the face of emotions such as anger or fear, the baby cries with his eyes open looking at the object or the person who caused the crying, while when they feel pain they cry closing sight with tension in the eye area and mouth open.
I suppose that not all babies cry in the same way to express pain, but it is interesting that gestural behavior patterns are investigated, as has been done with adults.
The authors of the study have developed a communication guide not yet published that could help parents identify each type of crying according to facial and vocal expressions, regardless of the sex or personal characteristics of each baby.
The interesting thing is that experts have said that they will extend the research to children under 3 months and that they will continue to analyze the crying of babies so that they can identify through it some types of pathologies.
In any case, for whatever reason, the important thing is that the baby's crying is always taken care of. I disagree in this regard with the opinion of one of the authors of the study that recommends after six months of the child "take special care not to attend to crying beyond what is strictly necessary", suggesting that crying is used by the baby to manipulate and as the only way to get what you want.
