Because no single characteristic defines intelligence, there can be no adequate process-based definition of intelligence. In principle, a combination of many empirically derived measures into a single index, as in a Binet test, would be appropriate. In practice, many of the relevant characteristics are simply impossible to measure. (Author/RD)

The Ravens Standard Progressive Matrices Test was administered to 48 subjects who then performed a card-sorting task under single- and competing-task conditions. Hick's Law and the Roth-Jensen procedure were used in task development. Complexity should have a more central role in speed of processing models of intelligence than ability to divide…