A. In 2008, at a German zoo, a gorilla (大猩猩) named Gana gave birth to a male infant, who died after three months. Photographs of Gana, looking stricken and inconsolable (伤心欲绝的), attracted crowds to the zoo. Sad as the scene was, the humans, not Gana, were the only ones crying. The notion that animals can weep has no scientific basis. Years of observations by biologists Dian Fossey, who observed gorillas, and Jane Goodall, who worked with chimpanzees (黑猩猩), could not prove that animals cry tears from emotion. B. It’s true that many animals shed tears, especially in response to pain. Tears protect the eye by keeping it moist. But crying as an expression of feeling is unique to humans and has played an essential role in human evolution and the development of human cultures. C. Within two days an infant can imitate sad and happy faces. If an infant does not cry out, it is unlikely to get the attention it needs to survive. Around 3-4 months, the relationship between the human infant and its environment takes on a more organized communicative role, and tearful crying begins to serve interpersonal purposes: the search for comfort and pacification (抚慰). As we get older, crying becomes a tool of our social interaction: grief and joy, shame and pride, fear and manipulation. D. Tears are as universal as laughter, and grief is more complex than joy. But although we all cry, we do so in different ways. Women cry more frequently and intensely than men, especially when exposed to emotional events. Like crying, depression is, around the world, more commonly seen in women than in men. One explanation might be that women, who despite decades of social advances still suffer from economic inequality, discrimination (歧视) and even violence, might have more to cry about. Men not only cry for shorter periods than women, but they also are less inclined to explain their tears, usually shed them more quietly, and tend more frequently to apologize when they cry openly. Men, like women, report crying at the death of a loved one and in response to a moving religious experience. They are more likely than women to cry when their core identities―as providers and protectors, as fathers and fighters―are questioned. E. People who score on personality tests as more sympathetic cry more than those who are more rigid or have more self-control. Frequency of crying varies widely: some shed tear at any novel or movie, others only a handful of times in their lives. Crying in response to stress and conflict in the home, or after emotional trauma (创伤), lasts much longer than tears induced by everyday sadness―which in turn last longer than tears of delight and joy. F. Sadness is our primary association with crying, but the fact is that people report feeling happier after crying. Surveys estimate that 85% of women and 73% of men report feeling better after shedding tears. Surprisingly, crying is more commonly associated with minor forms of depression than with major depression involving suicidal thoughts. G. People widely report that crying relieves tension, restores emotional balance and provides "catharsis," a washing out of bad feelings. The term "catharsis" has religious implications of removing evil and sin; it’s no surprise that religious ceremonies are, around the world, one of the main settings for the release of tears. H. Crying is a nearly universal sign of grief, though some mourners report that, despite genuine sorrow, they cannot shed tears―sometimes even for years after their loved one has gone. Unlike today, when the privacy of grief is more respected, the public or ceremonial shedding of tears, at the graveside of a spouse or the funeral of a king or queen, was once considered socially or even politically essential. I. Crying has also served other social purposes. Rousseau wrote in his Confessions that while he considered tears the most powerful expression of love, he also just liked to cry over nothing. J. The association of tears with art has ancient roots. The classic Greek tragedies of the fifth century B.C. were primarily celebrations of gods. Tragedies, like poetry and music, were staged religious events. Even then it was recognized that crying in response to drama brought pleasure. K. I have argued that there are neurobiological (神经生物方面的) associations linking the arts and mood disorders. When I lecture on crying, I ask my audience to let me know, by a show of hands, which art forms most move them to tears. About 80% say music, followed closely by novels (74%), but then the figures fall sharply, to 43%, for poetry, and 10-22% for paintings, sculpture and architecture. L. The physical act of crying is mainly one of breathing in air, which is why we choke up when we weep. This suggests to language scientists that emotional crying evolved before language, perhaps explaining why tears communicate states of mind and feelings that are often so difficult to express in words. Of course, from an evolutionary perspective, recognition of emotion (usually through facial gesture) was essential for survival. M. The earliest humans arrived several million years ago, but only 150,000 to 200,000 years ago, did cultures, language, religion and the arts arise. Along the way, tears became more than a biological necessity to lubricate (润滑) the eye and developed into a sign of intense emotion and a signal of social bonding. The development of self-consciousness and the notion of individual identity, or ego; storytelling about the origins of the world, the creation of humanity and life after death; and the ability to feel others’ sadness―all were critical parts of the neurobiological changes that made us human. N. More recently, we’ve learned from neuroscience that certain brain circuits (回路) are activated (激活), rapidly and unconsciously, when we see another in emotional distress. In short, our brain evolved circuits to allow us to experience sympathy, which in turn made civilization, and an ethics based on sympathy, possible. So the next time you reach a tissue box, or sob on a friend’s shoulder, or shed tears at the movies, stop and reflect on why we cry and what it means to cry. Because ultimately, while we love to cry, we also cry to love.Sometimes people cannot cry despite genuine grief.