Robert Cialdini spoke at the London-based Royal Society of Arts, Manufactures and Commerce about his book, The Power of Pre-Suasion, in 2016. What separates effective communicators from truly successful persuaders? The world’s foremost expert on influence reveals the results of three decades of research.

Cialdini’s research shows that the secret to persuasion doesn’t lie in the message itself, but in the key moment before that message is delivered. He visited the RSA to show that the best persuaders spend more time crafting what they do and say before making a request. In this way, they gain a singular kind of persuasive traction by arranging for recipients to be receptive to a message before they encounter it. Cialdini calls this pre-suasion. “To persuade optimally,” he says, “it’s necessary to pre-suade optimally.” In other words, to change minds most effectively, a pre-suader must change initial “states of mind.”