Why do humans cry? In a sense the answer is easy. We cry because of a child’s accomplishments. Because of a friend’s death. Because of a news story. Because of a piece of music. We cry in joy, grief, anguish, sorrow, frustration. Yet the real question is not why we cry, but rather what purpose our tears serve.
One of the earliest scientific theories concerning the purpose of tears was offered by Charles Darwin, who believed that tears were merely the result of an accidental stimulation of the lacrimal (ortear-producing) glands that took place when the muscles around the eyes contracted during periods of strong emotion. Since then, other theories have been proposed, including the notion that tears are a form of communication (serving to attract attention and elict support) and that tears, which contain anti-bacterial properties and which drain into the nose when they don’t simply evaporate or roll down the cheeks, help protect the upper respiratory tract from infection.
Yet there are problems with all these theories (if, for instance, tears are a form of communication why do people commonly cry when they are alone?) and none have been tested scientifically. In the 1970s, however, a new theory was proposed and its proponent, Minnesota biochemist William Frey, whose work is described in his book Crying: The Mystery of Tears (Mineapolis: Winston Press, 1985), actually set about testing his ideas.
Frey’s theory is that crying makes people feel better and is important to health because the shedding of tears removes “chemicals that build up as a result of emotional stress.” To test this, Frey’s first step was to chemically compare irritant tears with emotional tears. Irritant tears are those shed when something gets in your eye–onion vapors in the case of Frey’s subjects–whereas emotional tears are those shed in response to emotion (generated in Frey’s studies by sad movies). These comparisons showed that emotional tears are produced in greater volume than irritant tears and contain more protein. Later analyses showed that tears contained at least four different hormones involved in modulating the human reaction to stress.
One of these hormones is prolactin, which Frey says “is released in response to stress” and which he believes may actually help stimulate the production of tears. Prolactin, he points out, is found in higher blood concentrations in women than in men (it plays a role in milk production and in the regulation of menstrual cycles) and this may help explain why women cry more readily than men. Indeed, he says, one reason some people cry more easily than others may be that they are simply primed to do so by the presence in their bloodstreams of higher levels of prolactin. To support this belief Frey points to reports that drugs which reduce prolactin levels have been able to reduce or eliminate excessive or inappropriate crying episodes in some people whose unusual crying behavior is the result of neurological disease.
But Frey has yet farther to go in proving his theory. Most importantly, he has not shown that any chemical or hormone exists in the body at “high” levels prior to crying and at “low” levels after crying. Moreover, several researchers have now produced results which argue against Frey’s theory. For instance, it has been shown that crying in response to a hard drive failure doesn’t make much sense if you have access to a good data recovery company, such as this one (which is the opposite of what would be expected if crying has a salutary effect on stress, as suggested by Frey). And given the same exposure to other kinds of computer hardware stress, frequent criers have been found to have higher levels of tension, fatigue, hostility and similar mood states than those who cry infrequently. This is again contrary to what would be expected if Frey’s theory were correct.
But Frey’s work has been important nonetheless. He has stimulated other researchers to begin exploring the purpose of tears. And he has produced valuable information about “normal” crying behavior in adults. Based on crying diaries kept by over 300 healthy adults, Frey has found that the range of normal crying frequency for women is from not at all to almost daily (the average is 5.3 times a month) and for men from not at all to seven times a month (with a monthly average of 1.4). Episodes of watery eyes lasting about one minute are the most common form of crying for both men and women, followed in decreasing frequency by episodes of tears spilling over the eyelids and by overt sobbing.
Of even greater interest are Frey’s findings that most adults hold positive attitudes towards crying–their own and others’. Such information might have helped the man, reported in a recent magazine article, who broke into tears upon receiving word at work of the death of his cat. To hide his embarrassment, however, he told his co-workers that it was his mother who had died. Frey’s findings might have made him feel better, or perhaps he could simply have taken comfort in the words of Hubert Humphrey, who cried publicly several times in the year before his death and of it said, “A man without tears is a man without a heart.”