tained. Simultaneous processing involves processing of stimuli in which the stimulus as a whole must be comprehended or in which elements must be integrated into a meaningful whole. Successive processing concerns processes in which the sequence of the processing of elements is crucial, such as language. Factor analytic studies of the PASS model have been less than fully successful, failing to establish planning and attention as empirically distinct entities. Despite this, the Cognitive Assessment System (Naglieri & Das, 1997) provides a standardized battery to assess the components of the PASS model.

A second theoretical approach encompasses information processing theories derived from cognitive psychology. For example, Campione and Brown (1978) offered an initial model that was further developed by Borkowski (1985). Information processing models of cognitive ability often distinguish the architectural and executive systems, roughly equivalent to the hardware and software components, respectively, of a computer. The architectural system is assumed to be genetically, or at least biologically, based and consists of basic operating parameters of cognitive processes, encompassing individual differences in (1) amount of information that can be processed, which is assessed using memory span, (2) durability of information storage, or the retention of memory traces, and (3) efficiency of processing, or the speed of encoding and decoding information. The executive system encompasses components that are environmentally based and guide processes comprising problem solving. The executive system subsumes components such as (1) one’s knowledge base, or declarative knowledge of facts; (2) control processes, which include strategies or heuristics to aid memory or problem solution; and (3) metacognition, which involves, among other things, knowing how problems should be solved and then monitoring progress toward problem solution and evaluating outcomes to ensure successful solution of the problem. Researchers using the information processing approach have paid little attention to converting theoretical insights into usable measures of intelligence.

Sternberg (1985, 1986, 1996) has offered several theories of hu-