Anthony greenwald and his colleagues (1991, 1992) randomly assigned university students to listen daily for 5 weeks to commercial subliminal messages that claimed to improve either self-esteem or memory. but the researchers switched half the message labels. some students who thought they were hearing affirmations of self-esteem were actually hearing memory enhancement messages. others who were hearing affirmations of self-esteem thought they were listening to messages about enhancing their memory. the researchers found that