Scientist at the University of Zurich have demostrated how neurobiological factors can influence human behavior. They used nasal spray to give volunteers oxytocin, a hormone produced by the body, oxytocin has been shown to promote social contacts in laboratory test animals. The people who receive oxytocin showed more faith and goodwill towards their neighbor. For example, in the study, male college students who played an investment game were more likely to entrust their money to someone they did not known well.
The researches are not concerned about potential manipulation, however. It is not possible to make people unwittingly compliant by exposing them to oxytocin via the air conditioning, for example. The hormone would have to be sprayed directly into your nose for there to be a noteworthy effect.