Final answer:
Sociologists Robert and Helen Lynd shifted the focus of their study from religion to the effects of industrialization and urbanization in Muncie, Indiana, leading to the influential work 'Middletown: A Study in Modern American Culture.'
Step-by-step explanation:
Robert and Helen Lynd conducted an extensive ethnographic study in Muncie, Indiana, starting in 1924. Originally intent on focusing their sociological research on the role of religion in America, their findings redirected them to explore the implications of industrialization and urbanization. This shift in focus did not change their research methods but prompted a reevaluation of their study's purpose. Through surveys and interviews, the Lynds compiled data that showed a significant transition from rural farm life to urban living. Comparing Muncie in 1890 with their current observations in 1924, they discovered that most adults who once grew up on farms were now city dwellers. The resultant study, 'Middletown: A Study in Modern American Culture,' became a seminal work in the field, depicting a detailed portrait of American life during a pivotal time of social change.