The study examined children's interpretive strategies for verbally presented class inclusion tasks as related to socio-cultural background, age and level of schooling. A total of 298 black and white Zimbabwe primary school children took part in the study. Children's performance was considered both qualitatively and quantitatively. Significant social class related differences in children's skill orientation were found. However, no socio-culturally related differences in children's use of interpretive strategies obtained, although age and level of schooling accounted for a significant proportion of the variance in performance. Implications for psychoeducational practice as well as suggestions for further research are discussed.Since Piaget's (1963Piaget's ( , 1971) clinical observations associated the ability to classify with the developmental ages of 7 or 8 years, children's class inclusion reasoning has been the subject of a growing body of research. Piaget claimed to have demonstrated that during the concrete operations stage (i.e., 7-1 1 years of age), children developed the ability to classify objects on some inclusion criteria. In the typical Piagetian experiment, a child may, for instance, be shown a set of objects (e.g., buttons) divisible into two or more subsets (e.g., by colour, size or shape) and then asked to relate a subset with a more inclusive one (e.g., How many more buttons are there than round buttons?) If a child was able to make the within class observation that there are more buttons than say round buttons, he/she would have demonstrated classification or class inclusion reasoning. In Piaget's theory of the development of knowledge, the significance of class inclusion reasoning as an indicator of cognitive growth lies in that it has been considered a primary sign of the emergence of logical thinking, that occurs together with the abilities of conservation, seriation and transitivity (Inhelder & Piaget, 1964; Piaget, 1971Piaget, , 1977.Amongst the issues that have been considered in related research are, how performance on class inclusion tasks is related to age (e.