perhaps still the most significant work in the field was that of iona and peter opie, which departed from previous practice in britain; following work by dorothy howard in america and brian sutton-smith in new zealand, they relied on detailed observation of children for their evidence resulting in their work on "the language and lore of schoolchildren" (1959), "children's games in street and playground" (1969) and "the singing game" (1985). their extensive studies refuted the idea that the traditions of singing games were disappearing in the face of social and media change, and instead suggested adaptation and development. their work was highly influential and replicated from a number of locations, including america, where herbert and mary knapp, produced "one potato, two potato: the secret education of american children" (1976) and finland which saw 's "children's lore" (1978). wider anthropologically based studies include helen schwartzman's "transformations: the anthropology of children's play" (1978).