“Why would you ever trust a stranger with your hard-earned money? If someone shows that he or she trusts you by investing money with you, neuroeconomics studies have found that the receiver’s brain releases oxytocin. In addition, the more oxytocin released by people’s brains, the more they returned some of the invested money (which typically earns a large return) to the trustee. “- Paul J. Zak
Let us start our thoughts by defining oxytocin. Oxytocin is a “hormone used clinically to help begin or continue labour, to control bleeding following delivery, and to stimulate the secretion of breast milk“. http://www.britannica.com/EBchecked/topic/437006/oxytocin
Reason TV recently filmed Paul J. Zak. Watch and be amazed. I have included a couple articles I found where Zak explains his studies.