When Louise McSharry was pregnant with her first son Sam, now two-and-a-half years old, she had certain assumptions about what motherhood would be like. “I thought that overnight I would become this patient and benevolent creature, who would never use a harsh word and who would never be frustrated, and that all of my selfishness would go away.”

The couples were measured for physiological responses like heart rate and respiration. Later, trained coders analyzed the tapes for emotional responses such as anger, sadness and humor. “These give us a pretty good snapshot of the nature of their relationship,” says study senior author Robert Levenson, a UC Berkeley psychology professor.

This new term has become popular recently among Chinese netizens and it has a special meaning: getting married without a house, car, diamond ring or a proper wedding ceremony.