Science Daily
Originally published September 11, 2013
Researchers at the Stanford University School of Medicine have shown that oxytocin -- often referred to as "the love hormone" because of its importance in the formation and maintenance of strong mother-child and sexual attachments -- is involved in a broader range of social interactions than previously understood.
The discovery may have implications for neurological disorders such as autism, as well as for scientific conceptions of our evolutionary heritage.
Scientists estimate that the advent of social living preceded the emergence of pair living by 35 million years. The new study suggests that oxytocin's role in one-on-one bonding probably evolved from an existing, broader affinity for group living.
The entire article is here.