Note Previous Page Flexibility
Because a researcher doesn't pre-judge the issue by deciding in advance what is / is not important when studying social behaviour, they can react to events / ideas, follow leads, pursue avenues of research that had not occurred to them before their involvement with a group. Follow your nose...

In this respect, a researcher can test hypotheses and may be able to redefine possible personal pre-conceptions about someone's behaviour in the light of their experience in the group.