ScienceDaily (Nov. 13, 2009) A new study carried out at the University of Haifa has found that the hormone oxytocin, the "love hormone," which affects behaviors such as trust, empathy and generosity, also affects opposite behaviors, such as jealousy and gloating. "Subsequent to these findings, we assume that the hormone is an overall trigger for social sentiments: when the person's association is positive, oxytocin bolsters pro-social behaviors; when the association is negative, the hormone increases negative sentiments," explains Simone Shamay-Tsoory who carried out the research.
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