In 1984, Professor Robert Cialdini PhD wrote one of the best books on the principles of influence ever written. It was called, quite simply, Influence.
The professor researched his book by going under cover and posing as a job applicant, fundraiser, used car salesman and many other roles to test his theories and delve behind the obvious to discover the deep, underlying psychology of influence.
He distilled all this work into Cialdini’s Six Principles of Influence. Here they are: