For decades studies of the effects of schooling upon the development of logico-mathematical concepts focused on schooled versus non-schooled subjects’ performance on logical tasks designed to evaluate cognitive competencies as general and decontextualized abilities. The studies (see, for instance, Greenfield, 1966; Luria, 1976; Stevenson, Parker, Wilkinson, Bonnevaux and Gonzalez, 1978; Sharp, Cole, and Lave, 1979) generally show earlier and greater development in schooled children and adults than in their unschooled counterparts.