A neuronal connection between the tear duct and the areas of the human brain involved with emotion was established during human evolution facilitating the act of crying in response to emotion. No other animals are thought to produce tears in response to emotional states, although this is disputed by some scientists.

According to a study of over 300 adults, on average men cry once every month, and women cry at least five times per month, especially before and during the menstrual cycle when crying can increase up to 5 times the normal rate, often without obvious reason such as depression or sadness. It is more socially acceptable for women to cry then men, and among more often men than women (and other social circles) it is considered an indication of emotional weakness and discouraged.

Tears produced during emotional crying have a chemical composition which differs from other types of tear. They contain significantly greater quantities of hormones prolactin, adrenocorticotropic hormone, Leu-enkephalin and elements potassium and manganese.

Function

The question of the function or origin of emotional tears is still open. Theories range from the simple such as response to inflicted pain to the more complex including nonverbal communication in order to elicit helping behaviour from others.

In Hippocratic and medieval medicine, tears were associated with the bodily humours, and crying was seen as purgation of excess humours from the brain. William James thought of emotions as reflexes prior to rational thought, believing that the physiological response as if to stress or irritation is a precondition to cognitively become aware of emotions such as fear or anger.

William H. Frey II, a biochemist at the University of Minnesota, proposed that people feel better after crying due to the elimination of hormones associated with stress, specifically adrenocorticotropic hormone. This, paired with increased mucosal secretion during crying, could lead to a theory that crying is a mechanism developed in humans to dispose this stress hormone when levels grow too high.

See also

• Cri du chat
• Pathological laughing and crying

Further reading

• William H. Frey, Muriel Langseth (1985), Crying: The Mystery of Tears . Minneapolis. Winston Press.
• Lutz, Tom (1999) Crying: The Natural and Cultural History of Tears. New York. W.W. Norton. ISBN 0-393-04756-3.
• Walter, Chip Why do we cry?. Scientific American Mind Dec 2006, Vol. 17 Issue 6; p. 44.

External links

• "Boys don't cry?" - Damian Corless examines the taboo that still surrounds public crying, Irish Independent, August 8 2008
• Why we cry by John-Paul Flintoff, The Age, 30 August 2003.