The only other theory of emotional crying, offered by the anthropologist Ashley Montagu, saw tears as a means of lubricating upper respiratory passages that would otherwise be dried out by sobbing. Yet, Dr. Frey pointed out, ''Most crying episodes are not associated with sobbing, and sobbing, when it occurs, doesn't always come before the tears. Also, people who exercise vigorously breathe a lot but without crying.''

Understanding why people cry, Dr. Frey said, is especially important because ''in our society men in particular are discouraged from crying. If crying reduced the effect of stress, by suppressing tears we may be increasing our susceptibility to stress-related disorders.''

To gain a better understanding of the role crying plays in human life, Dr. Frey studied ''normal'' crying behavior in adult men and women. The several hundred emotionally healthy volunteers were asked to keep a complete record of any tears they shed over the course of a month. As might be predicted, the women in the study reported crying on an average five times more often than the men -five times a month versus approximately once a month. Furthermore, a much higher percentage of men than women did not cry at all in the course of the month. Forty-five percent of the men, but only 6 percent of the women, shed no emotional tears in the 30-day study.

There was also a wide range in crying frequency. Some women did not cry at all and other women cried nearly every day. ''These were all normal people without any psychological problems,'' Dr. Frey said. Women reported feeling a ''lump in their throat'' when they cried much more often than men did. Women shed flowing tears in about half their crying episodes, but in only 29 percent of the male episodes did tears actually flow. In the rest, the eyes welled up with tears but the tears were not shed.

''Not only do men cry less often than women but their crying is also less obvious,'' Dr. Frey remarked. Sobbing occurred in only 14 percent of the women's crying episodes and 10 percent of the men's. More men than women said they were able to stop themselves from crying, and many women said they could make themselves cry without an external cause by thinking sad thoughts.

Although men cry less often than women, when they do cry, the crying episodes last as long as a woman's -about six minutes on the average, Dr. Frey's study showed.

Dr. Frey also explored the relationship between personality and crying behavior and, to his surprise, found absolutely no correlation between various personality characteristics and the frequency of crying. For example, no higher crying frequency was found among people who scored high on scales of stress, alienation, impulsiveness, social distance and social impotence. On average, those who showed some evidence of current depression cried more often, but other depressed people did not cry at all.