LECTURE EXTENSION

1. The sensorimotor stage (birth-18 months). During this stage, mental structures develop as infants experience and interact with physical objects and people. Cognitive attainments include exploring objects, locating objects that have disappeared from view, transformations in eating and drinking, increased complexity in nonverbal and verbal human interactions, using vocalization for social purposes, assigning meanings to words, and producing recognizable words.

2. The relational stage (18 months-5 years). Development during this stage connects the sensorimotor thinking of infancy, which reaches its most advanced state in means-end behavior and tool use, with the logical thinking of middle childhood (on which formal schooling depends). Structures develop that enable the child to deal with spatial, social, linguistic, and number relationships. Cognitive attainments include spatial abilities (such as figure drawing and block assembly); social abilities (for example, the ability to put oneself in another's place; reading and influencing others' feelings); language comprehension and production; and counting.

3. The dimensional stage (5-11 years). A new type of thinking emerges that entails dimensional rather than relational thought. The child can consider several dimensions of physical, social, and spatial events. Cognitive development includes scientific reasoning, especially with respect to liquid quantity, projections of distance, and probability; the ability to classify objects along one or more dimensions; the ability to solve spatial analogy problems; and the ability to identify and label others' feelings, infer others' thoughts and capacities, and judge the "fairness" of social situations.

4. The vectorial stage (11 years and on). In this stage, the young person can deal with abstract material and explain or predict what will result from the interactions between two or more dimensions. However, the individual no longer focuses on either of the two dimensions separately, but rather on the more abstract vector that results from the interaction of the two dimensions.

Although Case's four stages are thought to be invariant, research by Fiati (1992; reported in Case & Okamoto, 1996) has indicated that as with Piaget's formal operational stage, Case's higher stages of cognitive development may not be reached in non-Western cultures that have no formal schooling. The group that Fiati studied lived in isolated, agricultural villages in the Volta region of West Africa. The villagers lived in traditional mud huts with no modern amenities, such as electricity, running water, or clocks.

In this study, Fiati found that the children in these isolated villages did not appear to reach the dimensional level of thought for number. Both their working memory for numbers and their counting speed were similar to those of much younger children who were receiving formal schooling in nearby towns. Clearly, this makes sense given that the Western (base-10) system of measurement was not used by the villagers and that their trade entailed direct barter rather than money. Moreover, mathematical computation was neither a highly practiced nor a particularly valued skill in these remote villages. On narrative tasks, however, these children showed levels of sophistication comparable to schooled children in nearby towns. This is perhaps because storytelling around a common fire occurred nightly following sunset.

Case, R. (1985). Intellectual development: Birth to adulthood. Orlando, FL: Academic Press.

Case, R. (1992). The mind's staircase. Hillsdale, NJ: Erlbaum.Case, R., & Okamoto, Y. (1996). The role of central conceptual structures in the development of children's thought. Monographs of the Society for Research in Child Development, 61 (Serial No. 246).

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