Final answer:
Early anthropologist E.B. Tylor used a cultural evolutionary approach to understand belief systems, placing cultures in a hierarchy from 'savagery' to 'civilization'. His narrow definition of religion as 'belief in supernatural beings' has since been expanded by later anthropologists recognizing more complex cultural interactions and definitions.
Step-by-step explanation:
Early anthropologists like E.B. Tylor approached the understanding of belief systems within different cultures with an evolutionary perspective. Tylor, as part of the 19th century anthropological movement, categorically placed societies into stages of 'savagery', 'barbarism', and 'civilization'. He suggested that cultures evolve from simple to complex forms, an idea that reflects the cultural evolutionism prevalent at the time. This approach often led to erroneous ethnocentric comparisons, with European cultures seen as the pinnacle of 'civilization'. E.B. Tylor's definition of religion as "the belief in supernatural beings" was particularly narrow and excluded many cultural nuances. However, as anthropology evolved, criticisms from scholars like Franz Boas and further research shifted the understanding of cultures towards recognizing unique historical trajectories and the diffusion of cultural elements through interaction rather than a linear progression.