Law of primacy in persuasion

In advertising and public communications, the law of primacy in persuasion as postulated by Frederick Hansen Lund in 1925 holds that the side of an issue presented first will have greater effectiveness than the side presented subsequently. Lund gave college students document in support of one side of a controversial issue and then presented a second taking the opposite position. He found the document read first had greater influence, regardless of which position it expressed. This empirical evidence was generally accepted until 1950, when Cromwell published findings of a recency effect in persuasive arguments that were considered statistically reliable.