Madrid: Pattern of crying reveals whether a baby is experiencing anger, pain or fear, according to a Spanish research.

"Crying is a baby's principal means of communicating its negative emotions and in the majority of cases the only way they have to express them," says Mariano Choliz, researcher at the University of Valencia.

Choliz co-authored the study with experts from the University of Murcia and the National University of Distance Education (UNED), the Spanish Journal of Psychology reports.

Their research describes the differences in the weeping pattern in a sample of babies between three and 18 months old, caused by three emotions: fear, anger and pain, according to a release of the Scientific Information and News Service (SINC) of the Spanish Foundation for Science and Technology (FECYT).

"When babies cry because of anger or fear, they keep their eyes open but keep them closed when crying in pain," Choliz says. Both the gestures and the intensity of the cry gradually increase if the baby is angry. The same pattern is also noticed in the case of pain and fear.

When a baby cries, facial muscle activity is characterised by lots of tension in the forehead, eyebrows or lips, opening of the mouth and raised cheeks. The researchers observed different patterns between the three negative emotions, pain, anger and pain.

As Choliz notices, when angry, the majority of babies keep their eyes half-closed, either looking in apparently no direction or in a fixed and prominent manner. Their mouth is either open or half-open and the intensity of their cry increases progressively.

In the case of fear, the eyes remain open almost all the time. Furthermore, at times the infants have a penetrating look and move their head backwards. Their cry seems to be explosive after a gradual increase in tension.

Lastly, pain manifests as constantly closed eyes and when the eyes do open it is only for a few moments and a distant look is held. In addition, there is a high level of tension in the eye area and the forehead remains frowned.

The cry begins at maximum intensity, starting suddenly and immediately after the stimulus.