ABSTRACT
A series of conservation tests of the Jean Piaget type was given to Mexican children in two separate locations. The concepts investigated were those of number, liquid, substance, weight and volume. Application of the tests followed the classic procedure of previous investigations, but translated into Spanish. An experimental group was composed of children who had grown up in pottery-making families. A control group was composed of children of matching age, years of schooling, and socioeconomic class, but whose families engaged in skills other than pottery-making. The guiding principle behind the choice of selecting children versed in pottery-making was that of the role of experience and specifically manipulation in the attainment of conservation. Manipulation may be a prior and necessary prerequisite in the attainment of conservation, but a skill embodies a set of operations with a recognizable end – making cups from clay for example.
