Compatible personalities are more important than shared moral values as a recipe for a good marriage, according to a study. Married couples often share the same attitudes about faith and other values, researchers from the University of Iowa found. But those with personalities similar to their spouses were the happiest. "People may be attracted to those who have similar attitudes, values and beliefs and even marry them," the researchers said, and those qualities are easy to spot in a potential mate. Attitudes toward subjects such as religion or politics "are highly visible," they said. But how married people behave was shown to have a greater effect on happiness.