Paul J. Zak’s book The Moral Molecule suggests that a chemical substance in the body, oxytocin, is connected to feelings of trust and empathy. The complete article is linked below, but I’ve reprinted the portion brides and grooms may find of particular interest–an experiment in the chemical’s effect at a wedding:

…Consider a real-life experiment that I conducted with a bride named Linda Geddes. A writer for the British magazine New Scientist, Linda had been following my research and thought it would be fun to see if the emotional uplift of her wedding would alter the guests’ levels of oxytocin.

I arrived at the venue, a Victorian manor house in the English countryside, with a 150-pound centrifuge and 70 pounds of dry ice. I unpacked my equipment—syringes, 156 prelabeled test tubes, tourniquets, alcohol preps, Band-Aids—and got to work. The plan that I’d worked out with Linda was to take two samples from a cross section of the friends and family in attendance—one draw of blood immediately before the vows and one immediately after.

After all the blood had been drawn, I slipped out with my test tubes nestled in their cushion of dry ice. It took two weeks for the samples to arrive at my California lab via FedEx, but the results showed just what we were hoping for: a simple snapshot of oxytocin’s ability to read and reflect the nuances of a social situation.

The changes in individual oxytocin levels at Linda’s ceremony could be mapped out like the solar system, with the bride as the sun. Between the first and second draws of blood, which were only an hour apart, Linda’s own level shot up by 28%. For the other people tested, the increase in oxytocin was in direct proportion to the likely intensity of their emotional engagement in the event. The mother of the bride? Up 24%. The father of the groom? Up 19%. The groom himself? Up 13%…and on down the line.

But why, you may ask, would the groom’s increase be less than his father’s? Testosterone is one of several other hormones that can interfere with the release of oxytocin, and the groom’s testosterone level, according to our blood test, had surged 100%! As the guests admired Linda in her strapless bridal gown, he was the alpha male.

Our study at the wedding had demonstrated just the kind of graded and contingent sensitivity that allows oxytocin to guide us between trust and wariness, generosity and self-protection. Should I feel safe and warm and cuddly in this crowd, or do I have to be on guard? Or maybe it is a situation in which the best outcome results from oxytocin dominating in one person and testosterone driving the other.

It is the sensitivity of oxytocin in its interaction with a range of other chemical messengers that helps to account for why human behavior is so infinitely complex—and why the bliss of the wedding day (and night) is often hard to maintain. (Consider the old joke about the guy who couldn’t understand why his wife was unhappy. “I told you that I loved you when I asked you to marry me,” he said. “I don’t see why I need to tell you again.”)…

Read more: http://online.wsj.com/article/SB10001424052702304811304577365782995320366.html?mod=googlenews_wsj