 The use of natural materials has been widely praised as fulfilling children's aesthetic needs, encouraging their imagination, and reinforcing their identification with nature, though one pair of reviewers questioned whether the preference for natural, non-manufactured materials is "a reaction against the dehumanizing aspects of nineteenth-century industrialization" rather than a "reasoned assessment of twenty-first century children's needs".Pre-school and kindergarten programs generally include seasonal festivals drawn from a variety of traditions, with attention placed on the traditions brought forth from the community.Waldorf schools in the Western Hemisphere have traditionally celebrated Christian festivals, though many North American schools also include Jewish festivals.