Before Jackie left for college, she told her friend Lisa that she thought sororities were filled with snobs and that she would never consider joining one. But during Jackie's first week on campus, she was approached by a sorority member who invited her to a social function and encouraged her to pledge. After Jackie attended the party, she told Lisa, “Sororities do a lot of good things for the community. They're really service organizations.” Jackie's change in attitude to match her behavior reflects what concept?