Attention Hillary

Dr Antonio Damasio of the Department of Neurology at the University of Iowa College of Medicine, said some may fear the findings could be used by those trying to gain people's trust.

"Some may worry about the prospect that political operators will generously spray the crowd with oxytocin at rallies of their candidates.

"The scenario may be rather too close to reality for comfort, but those with such fears should note that current marketing techniques - for political and other products - may well exert their effects through the natural release of molecules such as oxytocin in response to well-crafted stimuli.

"Civic alarm at such abuses should have started long before this study."