David Lancy (1983) in his major cross-cultural study in Papua New Guinea gives us a helpful introduction to the analysis of the values of Mathematical culture. He developed a stage theory to account for the differences he found in his research and compared his stages with those of Piaget. He first of all came to the conclusion that, regarding cognitive development culturally, it is not individuals who achieve concrete operational or formal operational stages, but rather it is societies which make such transitions (p. 169).