Dr. Oren Hasson of TAU's Department of Zoology says that his analysis shows that while tears do signal physiological distress, they can also function as an evolution-based mechanism to bring people closer together.
"Crying is a highly evolved behavior. Tears give clues and reliable information about submission, needs and social attachments between one another. My research is trying to answer what the evolutionary reasons are for having emotional tears," Dr. Hasson said.
"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," Dr. Hasson added.
His research investigates the different kinds of tears we shed - tears of joy, sadness and grief - as well as the authenticity or sincerity of the tears.
Dr. Hasson says crying has unique benefits among friends and others in our various communities.
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. 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," Dr. Hasson said.
The study has been published recently in Evolutionary Psychology.