Why do humans cry emotional tears?

Humans shed emotional tears in response to intense feelings, and the leading explanation is that crying evolved largely as a social signal that prompts care and bonding. The mechanism behind it is still not fully understood, and researchers do not agree on how much crying relieves distress by itself. [1] [2]

Psychologist Lauren Bylsma describes basal tears, which lubricate the eye in humans and most animals, and reflex tears, which respond to irritants such as onion fumes. Emotional tears respond to a very intense emotional experience, which may be distressing or positive. Most researchers believe emotional tears of this kind are unique to humans. [3] [1]

Infants cry in response to pain or distress, which Bylsma calls fairly universal in early development. In adults, the triggers widen. Vingerhoets proposes categories including physical pain, attachment-related pain, empathic pain, societal pain, and sentimental or moral feelings. Positive events such as weddings, reunions, or music can also bring tears, usually when the emotion is overwhelming. [3] [4] [1]

Surveys of hypothetical situations and of actual recent crying episodes give different pictures. People name big losses in the first case, but in practice conflicts, small failures, criticism, and sad films are common triggers. A feeling of powerlessness or helplessness, often mixed with sadness, anger, or fear, is described as probably the most common emotional trigger. The same source notes that an emotional event alone often is not enough; a person's state and the setting also matter. [4]

Charles Darwin called emotional tears purposeless, but later work points to a social role. The American Academy of Ophthalmology says tears facilitate social bonding and promote helpful behavior, and that crying is thought to have evolved from animal vocalizations. Gračanin and colleagues link visible tears to the long dependent childhood of humans. In their account, a silent signal could draw help from particular caregivers without alerting strangers or predators the way a loud cry would, so crying's main function is to promote social bonding and pro-social behavior. [1] [5]

Whether crying also makes the crier feel better is less settled. Bylsma's studies found people were more likely to feel better when they received social support while crying, or when the crying led to a resolution or a new understanding of the problem. People who held back tears, or cried in an unsupportive setting such as work, were less likely to feel better. She suggests the value of crying lies more in the social response than in its physiological effects. Cleveland Clinic adds that researchers do not fully understand emotional crying, though many emotions can activate the sympathetic nervous system and trigger extra tear production. [1] [2]