The new confidence of the industry was captured in a 1923 manifesto entitled Scientific Advertising. “The time has come when advertising has in some hands reached the status of a science,” it boasted. “It is based on fixed principles and is reasonably exact. The causes and effects have been analyzed until they are well understood. We know what is most effective, and we act on basic law.” Nothing, in advertising, was now left to chance: “Every course is charted. The compass of accurate knowledge directs the shortest, safest, cheapest course to any destination.”

Tim Wu, The Attention Merchants, loc. 178