The result of decades of peer-reviewed published research on why people comply with requests
“In the increasingly overloaded lives we lead, more than ever we need shortcuts, or rules of thumb, to guide our decision making. My own research has identified just six of these shortcuts, and universals, that guide human behavior. They are: reciprocity, scarcity, authority, consistency, liking and consensus. Understanding these shortcuts, and employing them in an ethical manner, significantly increases the chances that someone will be persuaded by your request.” - Dr. Robert Cialdini
Video: Science of Persuasion