Medically, crying is known to be a symptom of physical pain or stress. But now a Tel Aviv University evolutionary biologist looks to empirical evidence showing that tears have emotional benefits and can make interpersonal relationships stronger.

New analysis by Dr. Oren Hasson of TAU's Department of Zoology shows that tears still signal physiological distress, but they also function as an evolution-based mechanism to bring people closer together.

"My analysis suggests that by blurring vision, tears lower defences and reliably function as signals of submission, a cry for help, and even in a mutual display of attachment and as a group display of cohesion," he reports.

His research, published recently in Evolutionary Psychology, investigates the different kinds of tears we shed - tears of joy, sadness and grief - as well as the authenticity or sincerity of the tears. Crying, Dr. Hasson says, has unique benefits among friends and others in our various communities.

For crying out loud (and behind closed doors)

Approaching the topic with the deductive tools of an evolutionary biologist, Dr. Hasson investigated the use of tears in various emotional and social circumstances. Tears are used to elicit mercy from an antagonistic enemy, he claims. They are also useful in eliciting the sympathy - and perhaps more importantly the strategic assistance - of people who were not part of the enemy group.

"This is strictly human," reasons Dr. Hasson. "Emotional tears also signal appeasement, a need for attachment in times of grief, and a validation of emotions among family, friends and members of a group."

Crying enhances attachments and friendships, says Dr. Hasson, but taboos are still there in certain cases. In some cultures, societies or circumstances, the expression of emotions is received as a weakness and the production of tears is suppressed. For example, it is rarely acceptable to cry in front of your boss at work - especially if you are a man, he says.

Source: Tel Aviv University