DO WE HAVE TO CRY WHEN WE ARE SAD?
For Darwin, the emotions relate mostly to the parts of the body and the physiological mechanisms that have been conserved for reasons of general equilibrium, like serving as a counterweight for a segment of the body in the gravity field. This position is particularly well illustrated by the analysis of the expressions of sadness that Darwin develops in chapter 6 of his my yoga blog on emotional expressions. This discussion remains a reference in the literature on emotions.
The basis for Darwin’s analysis is the idea that a too rapid flow of blood to the eyes can raise the blood pressure at the back of the eyes, which can become dangerous.73 Every time that a person exhales violently while laughing, crying, or sneezing, there is an acceleration of blood flow to the face, which risks modifying the ocular tension abruptly. The dilation of the retro-ocular arteries sometime pushes the eyes forward and makes them appear as if they are bulging. A rapid increase in vascular blood activity in the eye unleashes a reflex that contracts the muscles around the eyes to diminish the flow of blood in the eyes. This reflex often produces tears.
For Darwin, the reflex that produces tears is not unleashed by exhalation but by the activity of the muscles that provoke the exhalation. If a person contracts the muscles of the thorax and the abdomen while holding his breath, the reflex around the eyes is automatically unleashed. There is also a risk that the eyes will become engorged when a person vomits or when the muscles of the belly are suddenly contracted to expulse a bowel movement. Releasing fluids can then help lower that pressure. This reflex is therefore useful for the health of the eyes.
In this discussion,74 Darwin indicates that many causes can activate the muscles used by a person who cries without it being necessarily related to sadness. It only consists, for the moment, of a reflexive sequence linked to the contraction of the muscles of the thorax and the belly. The first function of this reflex is to protect the eye when this type of respiration raises the pressure in it.