Fran Flanders, an Advice Columnist for a Regional Newspaper, Was

Fran Flanders, an advice columnist for a regional newspaper, was curious about why people are attracted to each other. She had a feeling that similarity leads to attraction, but she decided to conduct a scientific investigation to test her hunch. She found several couples who had been dating for a year or more and gave them a questionnaire that measured their attitudes and opinions on a variety of topics. Next, Fran gave the same questionnaire to several pairs of individuals who knew each other only as casual acquaintances. When she examined the questionnaire responses, lo and behold, she found that the attitudes of the couples who had been in long-term relationships were far more similar than the attitudes of casual acquaintances. "Great," Fran concluded, "I knew it all along! Now I can tell my readers that the key to good relationships is having similar attitudes!"
Do you agree with Fran's conclusion? Why or why not? If you were an experimental social psychologist, what approach would you take to testing Fran's hunch about why people like each other?