The Scientist:
Jonathan Rottenberg, Ph.D., associate professor of psychology, director of the Mood and Emotion Laboratory at the University of South Florida and author of “The Depths: The Evolutionary Origins of the Depression Epidemic

The Answer: Crying isn’t just reserved for sad moments. From weddings and graduations to sappy rom-com endings—many, though not all, people experience tears of joy as well as tears of sadness, anger or frustration.

Despite it being a widespread phenomenon, scientists are very much in the dark about why we can have the same reaction to very different scenarios. Indeed, crying at happy moments is actually something of a scientific mystery. Research has yet to map out what happens in our bodies or brains to trigger various types of tears, although all of them seem to be related to a feeling of attachment to someone or something. When something stirs up those attachments, cue the waterworks. It could mean sobbing mournfully at a funeral, or weeping with joy as your daughter gets her high school diploma or your best friend walks down the aisle.

Crying during happy times likely evolved because of its social benefits. When tears start pouring down our faces, it can draw other people in for social support or problem solving. It also may be that happy tears have a little bit of sadness mixed in. A parent at a graduation is filled with pride along with a feeling of loss as her child gets ready to move off to college. And you may be simultaneously thrilled for your BFF while also a little threatened at the new direction her life is taking.Surveys reveal that crying in positive contexts is less common that crying in negative contexts, and some people claim they rarely, if ever, cry at all. But if you tend to be on the weepier side of the spectrum, it’s probably a good idea to keep a hanky handy.

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