Em Griffin, The Mindchangers, Tyndale House, 1976, p. 179
A man named La Piere sent out letters to the managers of 256 hotels and restaurants across the southern half of the U.S. He told them that he was planning to tour the south with two Chinese companions and he wanted to know ahead of time whether they would be served. Ninety-two percent of the businesses replied that they did not serve Chinese and that La Piere could save himself considerable embarrassment by not showing up with such undesirables. He wasn't surprised. Racial prejudice was a part of southern life in the 1930s, and this was long before a ban was placed on discrimination in interstate commerce.
La Piere ignored the managers' advice, however. Accompanied by a Chinese man and his wife, he visited every one of the establishments that said they'd refuse service. Surprise! Ninety-nine percent of the places admitted the oriental couple, and almost all did so without a hassle La Piere's study points up something that's a consistent finding in the field of persuasion&md;that a person may say he feels one thing, and then turn right around and do something completely different.