02/28/2013 12:52 pm ET Updated Apr 30, 2013

Crying Is No Laughing Matter

Ask the question "What is the opposite of laughing?" and most people will say crying. While it is true that both acts convey via facial expression discrete emotions, and both are intimately involved in social interactions and bonding between individuals, they are quite distinct from many perspectives. People laugh much more than they cry. Laughing is often linked with telling jokes, but actually is most seen as a social gesture, for example when people greet each other. Laughing therefore most often occurs when someone is with other people.

Crying, on the other hand, occurs more frequently when people are alone. The feelings that go with laughing are quite short lived compared with those associated with crying which last much longer. Of course, it is situation dependent, some tears and hence the feelings, such as those after an unresolved domestic argument, or is settings of bereavement may last for a long time, while in other settings, the emotion is briefer. But it is of interest that most people report feeling better after crying, and this is the more so when tears are induced by social occasions, or are the result of being moved by an artistic or equivalent experience.

At the London Olympics in 2012, people around the world witnessed winners, losers, mothers, fathers, trainers and other spectators shedding tears after individual events, often linked with the podium displays and the singing of national anthems. In such settings, the music itself adds to the emotional intensity of the situation.

Music is one of the main artistic provocateurs of tears. With colleagues I have carried out surveys of people's responses to the arts, asking who cries to what events. Eighty percent will say they have cried listening to music; the number tearing while listening to or reading poetry is around 45 percent, while very few people confess to crying at an art gallery looking at a painting, or viewing a beautiful piece of sculpture or a wonderful building. Interestingly over 70 percent of people also can be brought to tears reading novels. Which pieces of music and the occasions of course vary, but music at religious ceremonies has invited participant' tears since at least the Middle ages, in the same way that modern cinema provides us with weepies.

It is universally found that women cry more than men. And in spite of the considerable changes of behaviour brought about by female liberation in the past forty or so years, the gender gap, that is the difference between males and females in the reported frequency of crying has not altered. Further, the gap does not appear until about the age of puberty. While this may suggest that the difference is in part related to biological factors, it may simple be that men are from Mars, and women are from Venus.

In my book, Why Humans Like to Cry, I contend that humans are the only living species that cries. Darwin thought the same, and I have no reason to doubt it. This does not mean that animals do not have a range of emotions perhaps similar to ours, but they simply do not shed tears for emotional reasons. Obviously tears have a biological purpose, keeping the eye moist, and, packed with antibiotic substances, minimizing infections. While there are many traits that have been suggested that separate Homo sapiens from other living species, it is my opinion that a truly distinguishing feature of is our ability to cry emotionally.

I argue that crying to emotional events must have both evolutionary and neuroanatomical explanations. These include the enhanced development of certain structures in the human brain and the structure of the face, which have increased our ability to communicate swiftly in very sophisticated ways, and have promoted social coherence and bonding between significant others. The ability to respond to the tears of another is linked with empathy, and the tear is the basis of a human morality founded on compassion. Crying is no laughing matter.